An excellent presentation. In fact that’s one of the best presentations on the subject of partial shading that I’ve seen. I was aware of the bypass diodes, but hadn’t considered the impact on the larger array. I think panels have evolved a little to include “half cut” cells. I think they run the bypass diodes up the middle of the panel, essentially doubling string number, and halving string length. It improves two attributes: - better partial shading performance - reduced diode hotspots, thereby improving panel life That diode heat loss can be a real panel killer. I did my own shading tests, which I think is in my Spring/June video this year. The direction in which shading is uncovered has a big impact on performance.
Coming from you, Anthony - that's praise indeed! Thank you. I might do a follow up on shading when I've collected enough feedback etc. and I'll be sure to include half-cut cells :-) And I remember your shading tests - I can't wait to be my own setup installed in January to do some of my own (I'll have relatively easy access to the panels as I have a number of Velux windows on my roof). I've had a bit of a nightmare with my solar journey, which started back in March! Let me know if you're interested to do something together on TH-cam at any time - I'd be game on for that.
Agreed, well presented. I’m breathing a sigh of relief knowing that I did do the right thing putting Enphase on my second array ( split across SE and SW facing roofs with chimneys ) Thanks
Direction of shade encroachment is indeed important. Most PV modules are wired as Gary illustrated so that the long edges each fall within one bypass diode zone. This is good for commercial ground mounted arrays facing South and with modules racked in landscape orientation. In that way the shade from the next most southern rack activates the minimum number of bypass diodes
how many strings can you break an array into? it seems like more wiring would be cheaper than optimisers or micro inverters, but there is a reason there are so many panels to a string and then the strings are in parallel; what are the limits?
Hi Scott, so it depends on your inverter. Most inverters only support two strings, but some can support three (or more). For each string, there is a minimum voltage level requirement before generation starts, so ideally, you want a lot of panels on each string to achieve that minimum requirement for longer in the day, especially if it’s cloudy. There is an upper limit on the voltage (and also current) which will be different for each inverter manufacturer.
Hi Nick - your comment has made my day! 😀 thank you! My next video will be a very short one talking about the difference between kW and kWh,…. and maybe a bit about voltage and current in there too - all using the water analogy 👍🏻
Hi Gary [- Truly EXCELLENT video - concentrating on technical detail on how panels work and the effect of bypass diodes. As a professionally qualified electricaland electronics engineer- I think the solar trade in general needs far more of this excellent level of instruction. ( Sadly lacking -you only need to read some of the forums to see how poorly solar power is understood, Having taken many so called "solar installer courses" from well known manufacturers - this video mostly stands head and shoulders above those - in terms of accurate well presented technical detail - not so such as to baffle people - but more than enough to understand properly what is going on Excellent !
What I have found with my own testing is don't buy normal panels, buy half-cell split panels, or BF panels, as they don't souther nearly as much from shading, and even on an overcast day they produce nearly as much power as my 2 year old LG panels do in full sun, and they have expanded my day by almost 2 hours. Thanks for this video, I found it very helpful. Subed.
Your channel is probably the best source of technical information about solar and battery systems on TH-cam right now, Gary. Many thanks for making such thorough and clear videos, I've learnt a lot from them.
Thanks Tim & Kat - that’s really kind of you to say 😀 When I looked into Solar for my own house, it was a real minefield of information and misinformation, so I thought I’d try to save everyone some time. Of course, once you release one video you kind of get hooked and spend countless hours putting together more 🤣🤣 Btw, I watched all your videos over the past few months. And am totally jealous of the 30% gas one - wow - and 1/3 million views and counting! 😳👍🏻 Keep up the great work!
@@GaryDoesSolar well, the time is very well spent, your video production quality is off the charts. I find it very amusing that you've been watching our videos in return. Ours are definitely a lot more rough and ready! It's funny, that first gas saving video was sort of intended for family and friends but then it went exponential which came as a bit of a shock. It turned out to be a double edged sword though as although it allowed us to join the TH-cam partner programme within two weeks it also came with a huge number of comments, which was a bit overwhelming. Most were very positive but a non-trivial number accused me of spreading misleading and dangerous information and even that I was going to kill people with my bad advice! It didn't matter that I got that advice from the Heat Geek channel and it was all perfectly accurate, some people still thought I shouldn't be giving advice if I wasn't a professional heating engineer. Oh well. I turned off the comments in the end and immediately felt a lot better! The internet is a funny thing, for sure. Our more recent videos are definitely a lot less controversial, thankfully. I look forward to whatever subject you tackle in your next video with great interest.
Thanks - that’s very kind of you to say. I’m certainly learning as I go. I need to improve my audio equipment as it’s different on and off camera. All the animations are done in (would you believe) Microsoft PowerPoint! Sorry to hear you were getting some adverse comments. This is certainly one of the hazards of publicising any kind of content - and yeah, with the reach you got with that video, the level of comments (across the spectrum) was always going to be high 🤣 I’m still able to respond to each comment, but if the channel grows further, I know I won’t be able to. What’s great is that the comments give me ideas for future videos - the shading topic is a great example as in an earlier video I said something about shading that turned out to be a complete myth! Lol What I like about your videos is that you’re highly relatable for everyone watching. And the fact that it’s “rough and ready” just adds to that. All the best with your channel. And I should be releasing a couple more videos soon (I’ve a back list of bay least 10 ideas so far - crikey! Just wish I had more time to actually make them!)
@@GaryDoesSolar PowerPoint! That's amazing, I never would have guessed. They're very effective, I have to say. Do you create the actual graphics yourself too? And I'd say your audio is fine, the difference between on and off camera is very marginal and hardly noticeable unless you're listening out for it. By the way, if you ever need to do any 3D models or animations give me a shout, I've got some experience with that sort of thing (do a Google search for Stone Baked Games, my other side project). Something I'm planning on doing at some point is creating a sort of 3D visualisation tool of a house with solar panels and adding a (reasonably) physically correct day/night cycle that can be varied by day of the year, so that folks could see the angle of the light landing on their panels at different times. I've worked out the maths, I just need to sit down and build the actual project! In the mean time I've been using the on-line tool you suggested in one of your previous videos, which is very handy. I also try to respond to all the comments I get (well, most of them) and at the moment it's just about manageable. But as you say, if the channel keeps growing that might become increasingly difficult. Thankfully the more recent videos have been almost exclusively positive, which I'm glad about. I'm glad you like our videos. I was hoping that they would appeal to some people at least and that does seem to be the case, thankfully. Like you I have ideas for loads more, and for every video I publish I get ideas for another five (often from what people say in the comments!). Keep it up, you're doing good work that I'm sure helps a lot of people, myself included!
Hi Tim, thanks - yeah I create all the graphics myself too - again in PPT - but now I’ve seen what you’re doing with SBG, I’m clearly an amateur!! And funny that I saw the sphinx and pyramids in the sunbeam trailer as I’m in Egypt just now! 😀 I like your 3D solar utility idea and I’d of course be happy to promote such on my channel in due course if you’d like 👍🏻
good video. When we set up our solar company, we had two systems installed. one partially shaded with microinverters, one with a string system also with shade. We demonstrate exactly what you are showing, but live in real life situations on our own home. Hearing from clients who have upgraded older string systems to Tigo and EnPhase is a real joy.
Thanks for watching my videos and taking time to comment. I’ll be doing a follow up on the shading one, and it sounds like you’ve great insight! If there’s anything you’d like me to cover in that, just let me know 👍🏻 All the best with your company! 😀
Quite a good video. I'll add a few other points that need to be considered: * When designing a string without optimizers, make sure that there is plenty of voltage margin verses the optimal 'operating' MPPT range of the inverter. For example, if the inverter's optimal MPPT range is 300-500V, you don't want the total operating voltage of the string to be anywhere near 300V. You want it to be higher so partial shading does not reduce the voltage to the point where it leaves the MPPTs operating range. Of course you also have to make sure that the string's open-circuit voltage does not exceed the inverter's maximum voltage (for an inverter like this, typically 600V). So in this example, having the nominal operating voltage be, say, around 450V, would be ideal. * Not all MPPT controllers are the same. When partial shading occurs, it changes the voltage-current curve that the MPPT controller sees. Sometimes the partial shading can cause a 'double peak' on the curve where one peak produces far more power than the other. If the MPPT controller fixates on the wrong peak, system performance can degrade well beyond what it should. So, for example, SMA's high voltage string inverters will do a periodic voltage sweep (usually every few minutes) to make sure that the MPPT is servo'd on the correct peak. * In variable shading conditions... for example, foliage on a windy day, the MPPT point may move around more quickly than the MPPT can track, resulting in additional performance loss. Optimizers and micro-inverters are able to track these quickly-changing conditions far more quickly than whole-string MPPTs can. But in most cases, such effects are minor anyhow. * People often make the mistake of paralleling multiple strings into a single MPPT. This results in far worse losses under partial shading conditions because any shade will cause the combined MPPT point to be non-optimal for BOTH strings. Thus, when designing a string system, always be sure to give each string its own MPPT and do not use paralleling (i.e. don't use a solar combiner box to parallel 2+ strings together). In modern day, it is really easy to dedicate one MPPT to each string, but older string inverters often had only one real MPPT controller. -- * Also, note that micro-inverters have the additional problem of back-hauling 240VAC instead of 400VDC, which means either (a) higher losses on the return wires or (b) requires lower-gauge (thicker) copper wires to backhaul the same amount of power. -- The bypass diodes are typically schottky diodes, each with a 0.3V volt drop when operating. Solar panels typically have three such diodes so if a panel is mostly shaded you not only lose the power from that panel, the string as a whole would also lose another 1V on top of that (per mostly-shaded panel). Bypass diodes basically allow current to flow one way with a voltage drop of 0.3V to 0.7V. The solar panel itself develops a voltage across the panel which puts the bypass diode into reverse bias, which basically turns off the bypass diode. When shading occurs, the open-circuit voltage of the shaded panel is STILL LIKELY TO BE VERY HIGH, far more than 1V. However, the load on the panel (in shaded conditions) quickly drops this voltage as the panel is unable to support the current the other panels are generating, which takes the voltage below 1V and essentially turns on the diode, allowing it to conduct the other panel's current. -- So, generally speaking, it almost never makes any sense to use optimizers or micro-inverters, but one must still be a little careful when designing the string system to avoid the pitfalls mentioned above. The only situation where micro-inverters or optimizers make sense are in quickly-changing shading conditions because their individual MPPTs can react more quickly to the changing conditions. But that's it. I definitely prefer high-voltage strings over optimizers or micro-inverters. -Matt
Wow - this is great insight! Thanks for taking the time to share with me. I'm considering a follow-up video on shading in a couple of month's time - and if it's ok with you, I'll try to include this insight (with credit given of course).
Great analysis. Maximizing the MPPT voltage is the key it seems, which means longer (i.e. higher voltage) strings are better. This also has the effect of extending the operating (time) window of the system (i.e. inverter on/off) closer to the peaks of consumption (i.e. morning and afternoon) so producing more useful output. Optimisers actually reduce the operating time window by reducing the string voltage slightly (thus resulting in later 'inverter on' and earlier 'inverter off' times), even when completely unshaded. Bit of a chocolate teapot IMO.
@@whirled_peas Didi you get that backwards? The higher the voltage, the lower the losses, not the other way around. Losses are governed by P = I^2 * R (power = current squared times resistance). For voltage and current, transmitted power is P = I * V. So for the same power transmitted, the higher the voltage, the lower the current on the wire. But losses scale to the square of the current so if you hold power the same and cut the voltage in half, losses will increase by 4 times. For 400VDC vs 240VAC, the 400VDC line will 60% lower losses along the wires. Of course it depends which country you live in. In some countries the utility connection to the house might be higher. But in most it hovers around the 200-240VAC range. This is also why advertised efficiencies for micro-inverters and optimizers are usually somewhat disingenuous. For micro-inverters it is because they don't count the higher losses on the back-haul. And for optimizers it is because you still have to add-in the losses from the inverter that the optimizers are tied into (thus going through an additional conversion). -Matt
I did a 2 panel test in series hooked up to a Bouge RV MPPT. Both panels getting full sun I covered one with a blanket. It took the watts to near zero for about 20 seconds but then the mppt adapted and gave about half of the 2 panel wattage. I think the whole panel has a bypass diode too that keeps one shaded from taking out the whole array. Two panels in Parallel reacted to one fully shaded panel a lot faster almost immediately halving without going to zero for 20+ seconds. This convinced me that parallel is best for small RV 12v systems. You never know when you will turn and have shade across a panel. Losing 20-30 seconds of power everytime would add up. I also saw an increase in heat for the mppt controller with the series due to higher voltage having to be downstepped to 14.4v. However Series is a must for higher voltage battery systems (24v or higher) or you can use higher wattage panels as an option.
Quite frankly this is exactly what I have been looking for. Excellent presentation, and excellent communication. Having had solar for three weeks now, no micro inverters and the potential of chimney shading, this video has totally relaxed my worry about not asking for micro inverters. Thanks Garry - you have a new subscriber!
@@GaryDoesSolar same situation here. I'm glad I've not performed a costly installation of optimisers on my 7 year old system. As you point out, the extra complexity increases your chances of failure and the benifits while there are not so big as to justify the cost. Also, very nicely paced clear explanation with good illustrations.
There are other reasons you would want to go with solar edge optimisers, #1 being the ability to oversize your panels and get access to dc power to charge battery or ev. Absolute game changer that your string inverters cannot entertain unfortunately
Excellent video, thank you. I was fretting about cable shading on my newly installed array, and couldn't understand why my panels were still generating when some of the stuff I'd read said they wouldn't. This has explained it in simple to understand language. Thank you.
As having no experience in this field you’re videos have given me a better insight to what I need to know before I make a final decision on what to install,I wish to thank you for making it a lot easier to ask the relevant questions,excellent videos
I've just read through most of the comments on this excellent presentation/video. There is really very little I could add. Extremely informative, challenging & clarifying supplier based information; excellent graphics. I suppose in summary, I feel in safe hands, without a hidden agenda. Thanks very much 🙏
That was is a fantastic video. I have just been quoted for 3 strings, 4,4,6. One of the 4 will be shaded by a gable over time and they quoted optimisers for them. This makes sense no. I would imagine they will go from the simple aerial apology to the chimney over the day. This has given me more confidence in the company I have chosen. They have quoted them for a good reason and didn’t try and stitch me up by only adding them to the string that needs them. On to your next video now
Hi Michael, thanks for the kind words! :-) And really great that my video has been useful to you in making your decisions around solar. All the best with your solar journey!
Very informative, thank you. If we ignore reliability of the bypass diodes for a moment, it looks like only part shading that does not trigger the bypass diodes is an issue in terms of generation (overall the system generating less than it actually could so to speak.) A quick search online suggests that bypass diodes can/do fail, and avoiding unnecessary load on them might be beneficial. In which case optimisers or micro inverters might have value in terms of long term maintenance/reliability, quite aside from slight increases in generation. HOWEVER, I am an amateur and quick searches online by amateurs often lead to mistaken beliefs… I have a house with quite severe local shading on much of the roof, that varies through the day and seasons, so have a more complex situation than anyone with no local shading issues. My feel at the moment is that I will be using optimisers or micro inverters.
As usual another extremely informative and useful video, I suspect it could save me a packet when we finally "take the plunge" early next year. However I suspect I'll be rewatching all of your videos before we make a final commitment . Thanks again Gary.
Great video. I might have added that the situation described applies to an array of identical panels mounted in essentially the same place which is probably the case for most new installations..
Very clear and informative. One advantage of microinverters is their ability to shut off power when the grid goes down. This is a safety issue and a requirement here in the US. If firemen need to go on the roof, series solar panels can present a dangerous HV DC.
Thanks Ken, for the kind words. And thanks also for highlighting this extra benefit. Although the videos on microinverters I've made up to now have been focussed on shading, I am going to make a video dedicated to microinverters, covering all of their benefits - I'll make sure to include this one :-)
I installed a new solar panel system 4 1/2 years ago. I live in the Desert Southwest of the USA where solar panels are a virtual necessity to prevent the power company draining my bank account. At the time I knew very little about the architecture of different systems. Like the vast majority of consumers I relied on contractors to recommend the best approach. Based on the recommendation of my installer, I ended up with a string array with a SolarEdge inverter/optimization. I’m lucky enough to have a large South facing roof with the one panel shadowed by a chimney that partially blocks sunlight in the morning. I’m a chagrined to learn that I could have saved a significant amount of money by eliminating the optimizers. I suspect that my installer, who is a very nice guy whom I trust, follows conventional wisdom in planning systems. I am going to share this video with him because I think he would be interested in lowering system costs allowing him to be much more competitive in pricing.
Hi Richard, I was lucky enough to visit your part of the world in the summer - had a great time there! And I can imagine why you were prompted to take action, to protect your bank account! :-)
@@GaryDoesSolar Hi Gary, I very much enjoyed your video have subscribed to your channel. Perhaps you visited my neck of the woods, Palm Springs, California. During the months of June through August we often have daily highs above 110°F. In the summer of 2021 we recorded two days at 123°F - which broke all previous records. On plus side, we have nice weather from October through May, with typical daily highs in the 70s F. Due to the purchase of an electric vehicle, I expanded my solar system from the original 12 kW to 15.5 kW. On a yearly basis I am at net zero electric consumption. I pay a few hundred dollars a year for grid use/maintenance/electric company profit. If I did not have solar, my electric bill would be around $5000 a year. I would be interested in a future video on panel cleaning. In May of this year I had a professional cleaning that cost me $125. The panels had not been cleaned in over a year and were covered with a layer of dust as well as small debris here and there. Due to a severe drought there had been no rain for many months. Consequently I expected the cleaning to yield a significant improvement in production. However, reviewing my daily solar production (using the SolarEdge app) I could not see any change from the days leading up to the cleaning and after (all were sunny days with no clouds). So I wonder if panel cleaning is a waste of money - at least in terms of solar production? I would be interested in evidence you may have found regarding this question.
Hi Richard, my wife and I were on a self-drive holiday from LA over to Monument Valley and back (in a huge loop). We were within 100 miles of you! Now, I haven't looked into panel cleaning but I'll add it to my stack (which has about 20 items in it currently, so I've no idea when I will get round to it). Wow - $5K a year is some saving! 🙂
@@GaryDoesSolar Let me know if you do get around to doing a segment on cleaning. I’d be happy to share with you my experience as well as what I see as pros and cons.
Nice explanation and definitely food for thought when deciding on the orientation of the panel based on likely hood of shading. If a wall or hedge is likely to shade the bottom of the panel late in the day it would make sense to have the panel in landscape orientation so only one string is bypassed and not all of them.
Thanks Gary. This video is a model of clarity. I have recently been mulling over the question of optimisers but, aside from generic 'marketing-speak', I had found very little in the way of hard information. My gut feeling was that, for my installation, optimisers would offer little benefit and your helpful video has backed this up and saved me quite a bit of cash 😀.
Our panels were installed 12 years ago and our installer went to the trouble of reducing the height of the top of our soil pipe and resiting our TV aerial. This means that our panels can never be shaded. Your video has explained why that was excellent practice. We were offered Solar Edge optimisers but neither our installer nor the manufacturer’s documentation could not explain what they did and why we would need them. I’m glad we didn’t buy them as you have explained why they would have been of little benefit with our installation.
The optimisers also provide arc fault detection, so fire protection and only provide 1V per panel open circuit so you can't get a fatal DC shock, you can also see each panel signals it's operating volts & amps on the Solaredge app, all besides each panel is doing its own mppt tracking.
Another method explained to help deal with this problem is to wire more parallel strings with less pannles in series. Not always ideal but it does work.
Hi Gary, As everyone else has said, this is another brilliant video - perhaps the best yet. The fact that you are very even-handed means, as you say, viewers can (and should!) make up their own minds on the subject. I've just placed an order for a 16-panel (8/8 east/west array)/5kWh battery system. At this time of year, we will have heavy shading on the west array (from about 2.30pm until about 5pm) from a large oak tree in a neighbouring garden. I've asked for Tigo optimisers on all of the west panels. We will have some shading on four of the east panels during the morning from a chimney. After some thought, I've decided to add optimisers to those four affected panels as well. I'm in discussion with Tigo at the moment about whether the Tigo Access Point (TAP) on the west array will be able to manage the additional four east panels. (The TAP connects to each optimiser by WiFi and is connected to the control gateway by a cable). When I started to watch your video, I wondered whether I'd specification the optimisers unnecessarily, but by the end my opinion is that for my situation I have made the right decision. Just a note on the point about costs: I've done a quick search for Tigo optimisers and the CCA (gateway) & TAP are available for about £60 & £400 respectively. Not an inconsiderable overall expense, but one which should, in my case, have a reasonably quick payback (I hope!).
Hi Phil - thanks for taking the time to comment in detail about your own situation. Yeah, I agree - optimisers are a good solution for you - and I would have taken the same approach. I'd love to hear how it all goes! :-)
Thank you. A very timely video for me as I'm in the process of comparing various quotes at present. I have tree shading issues so have been querying why optimisers are in/excluded from various quotes and why some quotes are only including partially optimised Tigo solutions. This is probably as clear an explanation of all the regular systems as I've seen (several compare Enphase and SolarEdge but very few include Tigo in the mix, which is what most companies are using in their quotations). Keep up the great work.
Thanks very much for the kind words - yeah, it's a real minefield out there, and hopefully, I'll continue to be able to demystify solar in my future videos :-)
@@GaryDoesSolar The good news is that I'm not yet an Octopus customer, so will definitely use your referral code when I'm eventually able to make the switch (not just for this video, but the entire series to date, which has been excellent). Not sure if you're aware, but they're currently closed to new customers until Octopus find a way to make them compatible with the Govt Energy Support Payments, as there's currently no way to include these on fixed rate tariffs, which is what the Go and Agile tariff rates are. It's very obvious how much work goes into these videos, so being able to use an affiliate code like this is at least a way to show support.
That would be very much appreciated, @@RiffMan117 - thank you! I’m using really basic equipment to make the videos (would you believe all the animations are in PowerPoint?!) My audio is all over the place, so I’d be using referral monies to buy better equipment 😀👍🏻
Great video, Gary. The time and care you clearly take to produce such professional presentations is definitely to your credit (not entirely sure about the start and end music, but hey that's personal taste!)
Hi Chas, thanks very much for taking the time to tell me this - it really means a lot. I agree about the music - it's a bit tacky and I'll change it before long! :-)
Great video. We have optimizers and I am quite content with them. We have 92 panels on our apartment building. We have an east--west orientation with a raised edge around the flat roof and a chimney in the center. You can follow the output of each panel through an app and usually there are significant differences. If you have panels in different orientations, you have to make either separate strings, each with their own inverter or use optimizers/micro inverters. Micro inverters make sense if you don't have a large number of panels. It's not only about direct sunlight shading. In clouded weather (diffused light) all panels are affected differently by sources of shade and no cell will have 100% shading. Also, dirt on panels can reduce the output of some cells more than others. Long term if we have to replace some panels by non-identical ones, that will not give us any issues.
Agreed - having the ability to individually monitor a large array of panels is a great benefit to have! I'll cover some of the points you make here in a follow-up video I'm making, especially about non-identical panel replacement... thanks!
You forgot that you can make multiple strings with a main Inverter that support 1 ~ 4 string groups. Or use multiple smaller inverters (given that you have 92 panels) that each take 1 or 2 strings, and output in parallel. The problem with micro inverters as i see it, they are exposed to potential hot temperatures, constantly with no cooling. That will affect them, despite the claimed 25 years warranty, vs a larger inverter that has active cooling to keep everything nice and cool. Take it from somebody in the IT business, there is a reason why datacenters have AC, and servers are stacked with loud fans. Electronics , and yes, that micro inverter has electronics in it, will degrade faster. And wait when one or more dies and you want or need to replace it. Its one thing on a apartment building with easy access but normal homes where you may need to remove a bunch of panels to access the issue panels.
@@benjiro8793 We have optimizers, which have less electronics in it than microinverters. Our rooftop has good accessibility for replacing broken optimizers. Multiple string groups requires more cables, which is significant, because the inverter is in the basement. We may not have the most economical solution, but I am content with it. Electricity production is above expectations.
Good video and well explained, one that I can point customers to!! been on about this for years, in these situations we parallel connect if some of the array will be shaded, we also combine series and parallel connections. Keep up the good work
Thank you so much! Yes, please feel free to share my videos with your customers. My next one will be explaining all the energy terms: kW, kWh, voltage, current, single phase, 3-phase, frequency etc.
In Australia it is possible to get Enphase micro-inverters at only 10% more than a string inverter. One of the most important benefits not listed here is the increased reliability and longevity of micro-inverters; our local supplier recently switched to offering only Enphase micro-inverters for that very reason. There are also significant benefits for PV installation companies in terms of managing and storing stock. Having inspected several houses and businesses with non functioning solar systems, I believe the improved monitoring from micro-inverters is well worth that extra investment.
@@GaryDoesSolar Enphase IQ8 microinverter has a 1/500000 failure rate and will function accordingly for 25 years, longer of course but that is the limit of the warranty, works when the grid is down without the need for a battery. The options focus on in this video will have to be replaced at least once, possibly twice during the life of the array. Those are undisputed facts and serious considerations. The solar industry is pushing for a module life span of 50 years, None of the tech featured is capable of such a feat. String will die a natural death, the future demands innovation. Ultimately customer service is the reason Enphase is number one in the USA and hyper-growing in Europe.
Thanks Don - I was careful not to draw firm conclusions one way or another. But I did want to get the point across that any improvements with optimisers are only marginal. If I had shading on my roof, I would like get optimisers for the affected panels, even just for the monitoring.
@@GaryDoesSolar Hi Gary. Thank you so much; these are fantastic videos which are so much easier to understand than just reading manufacturer's literature. I do have a question/observation. I've watched your earlier video 'How to choose SOLAR wisely and avoid costly mistakes' where you explain what each component does in a SOLAR system i.e. Solar panel, Invertor and batteries. In the Solar panel section, you mention that shading one panel will adversely impact all the solar panels in the series which suggests using optimizers and/or microinvertors is the only solution to reduce the impact of shading. However, your video 'Solar panels shading : Are optimizers and microinvertors worth it' you clearly explain that electronic protection measures are in place by having the bypass diode added to each array leg suggesting that optimizers and microinvertors are probably not worth the investment as the bypass diodes do a great job. Also, the cost of replacing the optimizer could be high for the reasons you explain. Maybe it's just me but I felt the videos slightly contradicted each other in the Solar panel sections. Let me know your views. Keep up the great work. Cheers
Misses out a lot about optimisers here. The string number lengths can be much longer, meaning that much more often you can have just one string down to the inverter. You can also parallel different length/orientation strings together (some conditions apply) Also orientation of panels in the string doesn't matter so much due to individual mppt. Open circuit voltage is only 1V per panel giving both panel signalling to an app for each panel's parameter indication and inherent arc fault fire protection.
Hi David, apologies - I thought I had replied to your comment already, but I see it’s not there. You’re right - on the earlier video I bought into the general perception that shading on one panel would affect all the other panels in the same string. Upon receiving a few comments for that video talking about bypass diodes, I decided to do some research myself, which concluded in the later video. It’s not really possible to modify videos once published but you can place correction markers, which I did. They may not always be displayed though depending on the device/app being used to view the video. Thanks for the kind words regarding my videos - much appreciated 👍🏻 😀
Hi Jeff, the features you describe are more advanced and I didn’t want to overwhelm the audience with what is essentially an introductory video into Solar PV shading. I’m now making a follow-up video though and will incorporate some of these into that. Thanks 🙏
A very good quality presentation. It might be worth checking the minimum operating voltage of the string inverter, as this may come into play if the shading is across several panels stops it from operating all together. If you have dramatic shading, like I do on my garage and only space for 6 panels, then Enphase IQ7+ microinverters are the only real option. There is also something called sub-panel optimisation where by you can replace the 3 bypass diodes with a small circuit that will optimise each of the 3 strings of cells. These were in the form of the Jinko Cheetah Maxim optimised panels - which I believe are now obsolete. It is a pity they did not continue this idea with more panels. So I am looking at building some of the modules to retro-fit to a test panel, the IC that forms the heart of this is the Maxim MAX20800. This involves removing the silicon potting compound and diodes and fitting a small PCB and re-potting it to waterproof it and conduct any heat away. Its worth also mentioning that the panels do not need to face the sun to produce power, as I have mounted a panel on the west vertical wall of my garage to take advantage of the setting summer sun, but even in the autumn/winter when the panel does not get any direct sunlight, I can still see perhaps 160Whr on a part sunny/cloudy day with the sun bouncing off the clouds and 60Whr on a clear blue sky sunny day.
Hi Rob, thanks for the kind words. And thanks also for this detailed comment. Lots of information in there for me to work through, especially as I'll be making a follow-up video on the shading topic soon... I love it that you're not frightened to get stuck in on the bypass diode circuitry! :-)
Hi Gary. Thank you so much; these are fantastic videos which are so much easier to understand than just reading manufacturer's literature. I do have a question/observation. I've watched your earlier video 'How to choose SOLAR wisely and avoid costly mistakes' where you explain what each component does in a SOLAR system i.e., Solar panel, Invertor and batteries. In the Solar panel section, you mention that shading one panel will adversely impact all the solar panels in the series which suggests using optimizers and/or microinverters is the only solution to reduce the impact of shading. However, your video 'Solar panels shading: Are optimizers and microinverters worth it' you clearly explain that electronic protection measures are in place by having the bypass diode added to each array leg suggesting that optimizers and microinverters are probably not worth the investment as the bypass diodes do a great job. Also, the cost of replacing the optimizer could be high for the reasons you explain. Maybe it's just me but I felt the videos slightly contradicted each other in the Solar panel sections. Let me know your views. Keep up the great work. Cheers
Thanks David, for the kind words. Really great to hear you’re loving the videos 😀 Yes, you’re right. In the earlier video, I feel I was duped by marketing material and also many TH-cam videos that claimed shading on one panel would affect all the others. It was only when someone mentioned bypass diodes in the comments to that video, that I thought I should undertake my own research to get to the bottom of it all. And I’m glad I did! Now, I added a correction to the first video but I guess it was not prominent enough - it should state “CORRECTION“ at the appropriate point in the video with a link to the later video…
This is the first video I've seen to clearly explain the pros and cons of optimisers.I assumed I needed them. I'm not sure the benefit of individual panel monitoring and a small improvement in efficiency can justify the cost.
Hi great video, I’ve some companies installing the optimisers in the loft ,by simply rooting the optimiser cable under the felt , so if any optimiser issues, being in the loft makes easy access and no need for scaffolding,
Nice video, and well put together. I'd add 1 more con to your list of optimizers 1. A constant 2% efficiency loss at the optimiser itself, regardless of shading or direct sunlight. I feel that most PV systems do not require optimizers/micro Inverters, but they do have their place in more difficult roofs with unavoidable shading. Good survey and design mitigates the need for optimizers in most cases in my opinion.
Gary I send all my customers in 2 minds about shading to your video and encourage them to use your octopus referral code- thanks for your comprehensive research
Hi Aaron, that's so very kind of you to do that - thank you! I think some have signed up as well :-) You've very welcome regarding the video content. All the best!
Thank you!! Of many analyses I read and watched about this topic, you are the first to mention the difference between hard/intense shadow and diffuse shadow where the bypass diodes don't kick in. That's the missing link! We've got two nearby buildings higher than our (southern) roof and their (hard) shadows wander across our roof during winter. But there aren't any high trees, cables etc. nearby. So if I understand correctly, the most that I need is a decent mpp tracker and a clever orientation of the modules (because building covers up the lowest meter or less off the roof traveling from one side to the other, the modules (~1.7m x ~1m) there should be installed horizontally), correct? Now I just have to find out whether 1mpp tracker is enough (all modules go on one side of the roof).
Thanks Thomas - great to have feedback like this. Now, if your solar panels are of the half-cell variety (see part two of my shading videos) then you could still mount those panels in portrait format on the bottom row. And assuming you're planning to use a string inverter with two strings, you could ensure that all the panels along the bottom are on the same string, which will help with tracking. Alternatively, you could look at having optimisers on the panels along the bottom row - but given these problems are only during winter, I'm not sure that this extra expense would be justified. Good luck with whatever you decide! :-)
@@GaryDoesSolar Thanks a lot for the helpful reply! Yes, half-cell, and yes, inverter with 2 strings (and 2 mpp trackers), but I am also thinking about extending the setup to the garage in the not-too-far future, so will ask my electricion if it makes sense to then go for an additional (smaller, 1-string) inverter or whatnot.
This is a really nice overview of what the optimisers can and can't do. How often is shading extreme enough to actually trigger the bypass diode? Shaded but not bypassed seems to be where optimisers would work best. Even though they add cost they should reduce the fault finding time if a panel goes bad and can allow you to have different panel angles and positions without multiple string inverters.
Thanks Andy - great to get feedback like this. Now, I read that bypass diodes will typically kick in when they detect a 20% difference in current. And I agree, if my roof had shading, I'd likely put in optimisers on the shaded panels just for the monitoring capability.
It is very rare for a panel to go bad. The probability calculation is not in favour of oprimisers. Even with untriggered bypass diodes, the optimisers gain only
@@GaryDoesSolar the bypass diodes are Schottky diodes, and they block the current in reverse, and conduct when the is a potential on 0.1 V accross them in the forward direction. @ 10A, they will dissipate 1W of heat. This is a failure point of cheaper panels that use cheap under sized diodes. A 3 or 5w rated diode should be used to ensure longevity. The diode is simply a one way valve. From Wikipedia Schottky diode page: "... Reverse current and discharge protection Because of a Schottky diode's low forward voltage drop, less energy is wasted as heat, making them the most efficient choice for applications sensitive to efficiency. For instance, they are used in stand-alone ("off-grid") photovoltaic (PV) systems to prevent batteries from discharging through the solar panels at night, called "blocking diodes". They are also used in grid-connected systems with multiple strings connected in parallel, in order to prevent reverse current flowing from adjacent strings through shaded strings if the "bypass diodes" Effectively, if there is shading and the panel or string becomes effectively open circuit, the rest of the string, eg 300v, easily pushes past the 0.1v required turn on voltage of the diode, and current then flows past, bypassing the open string. Simple and effective.
Thank you! This particular one took quite a while to put together! I need to try and get more efficient with the recording and editing - that's just as hard as getting the content together! Lol
Thx. Great. Very clear and educational. I have been searching this and now the yt algorithm keeps popping up these vid s about string vs optimized panels. This one is very good!
Thanks - it’s really hard to get traction on TH-cam as there are soooo many videos being produced all the time! Great to see that my videos are getting some exposure 😀😀👍🏻
In addition to cons of optimizers (and microinverters) being cost and additional failure points, there is also lost efficiencies of having them in the system. For instance, the Tigo and Solar Edge optimizers are active devices which themselves consume power. So in a largely unshaded installation, the overall power output is typically greater without those parasitic device losses.
I have to say that was a great video I had no idea that the solar panels with micro inverters had those bypass diodes which makes them much more immune to shading problems .
Very interesting and useful! Wish I had seen this before I had my system installed a coupe of years ago. I think the point about simplicity is very important. I just had one of the solaredge optimisers go and whilst solaredge sent a replacement for free it cost £150 + VAT to replace. (my installer has ceased trading - probably to wipe the slate clean - and it was just outside the 2 year insurance backed warranty) That's a big hit on the payback of a single panel, which is even worse when you consider the marginal benefit provided by the optimiser. solaredge optimisers do not seem to be that reliable? My panels are on a single pitch of a bungalow to easy access. Seems anyone with a high roof and difficult access should seriously consider if optimisers are worth it I was surprised that the optimiser can rescue nothing from a panel where the partial shading has tripped all the bypass diodes. Maybe we need to consider exactly how the shading will fall and select panels to minimise that issue? Do different panels have different diode orientation?
Sorry to hear about your bad experience with the failed optimiser. I agree, they provide only marginal benefit in many cases, against a high cost to fix in the event of failure. There doesn’t seem to be enough margin in the manufacturers’ products to allow for a better warranty payout :-(
Very clear and informative: thank you. I had understood that optimisers did have a downside of 'stealing' one or two percent of the power from a cell permanently. So that while they may help in complex shading scenarios, they do extract a price to do so. Is that your understanding too? Best wishes. Michael
Great presentation, thanks for sharing, when you run out of ideas this topic can be extended to half cut cells modules and having strings in parallel how this is being affected. Having one bigger string or having 2 strings half the size in parallel. Again thanks for sharing:)
+1 for maybe looking at what happens with panels in parallel. As I understand it, this solves a lot of problems with shading in a series/string setup, but only if your inverter / charge controller works with the lower system voltage (due to the panels being in parallel rather than a series string)
Thanks Jamie. Certainly, parallel panels allows the current another route round in case of shading on one of the panels. I'm planning a follow-up video on shading in a couple of months and will try to cover this.
That is the best presentation of the pros and cons of optimization that I have seen. Thanks! SMA says they have a new MPPT routine for their string inverter that works as good as optimizers in some circumstances without the reduced reliability. Have you figured that one out yet?
You’re most welcome, Mark. It’s great to get feedback like this, as my aim is simply to demystify everything. Now, I didn’t know about the new SMA MPPT routine - I’ll check that out… 👍🏻
There are two more scenarios I can think of in which you can use optimizers: - you can have one string with some pannels placed at different angle on the roof or facing different direction - you can have pannels with different power output connected in one string I know that these are not good scenarios and should be almost always avoided, however they are possible with optimizers.
Not sure which products can ‘can cost the same as the panel’ but I know the basic Tigo is about £40. Interesting video though as my issue will be solid shadow from a chimney going right through an entire panel which suggests an optimiser will be pointless. Thanks for posting.
I think your best option would be to avoid putting a panel within that area, BUT I know that is very easy to say in a comment without knowing the whys and wherefores.
@@GaryDoesSolar I'm sure it did as you can tell by the graphics and references you found to back up your explanation and reasoning and what people don't understand is the time ot takes to find what you are after and then to cros check what you have fojnd to make sure that it is correct. This takes ages. People in general just see the presentation and just assume that it has been grabbed and don't realise that research takes an incredible amount of time. Probably due to a lot of people just taken a source at face value and don't cross check. No, it is a very informative video as your others have been btw.
Nice video, well presented. I do think you missed one aspect - in all your examples you are referencing a single serial string if panels. I think that it's fairly common to have parallel strings with (passive) combiners driving into a single charge controller/invertor. If one string is shaded it's voltage will be reduced, compared to the other (parallel) strings. It would be interesting to see how this manifests - I suspect that you would loose all of the power production from that string. It's also worth noting that if parallel strings are placed on different aspects of a roof that the same situation can occur... If at all possible panels should face same direction, or be wired on different charge controllers.
Thanks for the kind words. I'm getting quite a lot of interest in this particular video, and suggestions (including those you raise) for a follow-up video - so my plan is to work on that soon :-) I really appreciate you taking the time to comment
Another awesome video Gary.👍👍. The only benefit as far as I can see is the ability to check how each panel is working. Might be useful for the photon geeks? Have you seen the Australian TH-camr: Off Grid Garage he demonstrates Hyundai shingled panels with a voltmeter and fries his voltmeter entitled "Hyundai Shingled Solar Panels - 15% better than other solar panels?"
Hi gary, fitted 4 TIgo optimizers to my string on 4 panels that get shading around 2-4 o'clock. Have noticed no improvement with using them, so will be selling them on ebay.
Thanks for sharing this Jon - it sounds like you've got an installation then added the optimisers to see if they would improve generation because of the shading, but in actual fact, there was no change. If so, this is better empirical evidence for folks to consider, and I hear so often from people who had optimisers fitted from the start, that they're doing the job... but how would they know? And as you're talking about Tigo products, it looks like the company has some interesting problems to deal with - see this article on reddit: www.reddit.com/r/solar/comments/144j15k/tigo_ts4_modular_level_power_electronics_melt_down/
Hi Tony - thanks very much. Now, I've not heard anything yet - and hoping they'll will see I've been objective and also have simply quoted their own materials. I'd certainly be happy to record a video with them if they wanted to extol the benefits of their products... :-)
I need to get me some bypass diodes. I always wondered what they were for, i thought it was to stop power flowing back into any potentially weaker panels during certain situations or if a problem arose in one of the panels.
Just food for thought to consider cost benifit is the ease of system diagnostics with the panel level monitoring that solar edge and enphase offer apart from Sma and fronius. The average homeowner doesnt have the knowledge to know when something is off at the panel level (diode issue, multi cell degradation). Also the fact that that enphase is modular system for reduced production loss with any defective equipment. Ive installed and serviced thousands of site between all manufacturers. There alot more after the fact to consider rather than just the unfront ideology.
Very informative video. Thanks for that tip. I have 3 different solar power systems that I own. 2 on the RV's and one on our house. the house has the Enphase micro inverters and the RV's both have NPPT controllers. Only one of the RV's uses an inverter. On the one RV I have seen a low or no output situation, as the solar panels had not been cleaned in quite a while. I thought it very odd that with 800 watts of possible output that the controller showed only the low battery voltage. I think it was around 8V, not enough to power the inverter or even the LED interior lights. Now I understand why that happened. I have a video about my 3 systems posted, if you'd like to check it out. I'd be very interested in your evaluation of my 3 different systems. I guess now I have to go clean a few solar panels!
Hi Gary, very informative video thanks. I'm just in the process of designing a system at home and wondering if I needed optimisers. I'm still not 100% sure, can you clarify what your diagram shows at 16:45. If I have 2 panels out of a string of 6 that are not producing any current, without optimisers are the other panels still able to push current through the shaded panels? I thought if all the panel was shaded it would block the current.
Hi Kieron, great to hear you got a lot from my video 😀 So, in the video then: if there were no bypass diodes in the panels, any fully-shaded cells would completely block current flow in that panel and also for all the other panels connected in the same string. The bypass diodes essentially “detect” shaded cells then re-route (bypass) current around them - to the extent where if a whole panel is shaded, the three bypass diodes in the panel will simply bypass the current through themselves, avoiding all the cells in the panel completely. Hope this helps!
The video was well explained. I have a better understanding now. Still I have some concerns. (Time frame 16.01, what if the panels which are shaded is only having optimisers, will it give the same result, how mppt works in this case.) Does the optimiser in a panel will help that specific panel to improve the power output.
Thanks for your kind words, Amrutha. Yes, if only the shaded panels had optimisers, the output would be just the same as all the panels having optimisers. Each optimiser acts only on the panel it is managing, and it will bypass current around the panel if it is not performing as well as the others.
Gary I am considering solar. I have a roof which faces directly SSE 150 deg. It has 0% shading. No adjacent roof lines or chimneys or power cables. Clear unobstructed views. Effective arc of sun say 90 - 210 deg . I live in Kent UK. I believe it could fit 12 panels. The only shading occurs via sun rise to the east and then suns transit to the west. Say summer the roof is Not in direct line of sight of the sun by 1800. Still day light but not direct. Would the solar system conclude that with no direct sunlight system shuts down or significantly reduces power, I think the latter? Also with 0% direct shading that micro inverters would be overkill and possibly optimisers are not required??? Your views would be appreciated. And yes I have subscribed and like. Regards Steve.
Hi Steve, great to hear you’re starting your solar journey! Now, I receive many questions about individual solar setups and specific needs, and while I’d love to respond to everyone personally, my time is unfortunately limited. The good news is there are fantastic online communities, like this UK solar and battery group, where experienced members are more than happy to share free advice and support: facebook.com/groups/2197329430289466. If you're based in the UK and looking for more personalised guidance, I also offer a "Chat with Gary" service. While it’s a paid option, it allows us to dive deeply into your unique situation and find the best solutions for you: garydoessolar.com/chatwithgary/. I wish you all the best in your solar journey, and I hope you find the perfect solution for your needs!
I manage about 10MW of rooftop solar across the UK. Of that about 20% is SolarEdge. It is entirely fair to say the the SE systems do produce more than an equivalent string inverter system. It's in the order of 1-2% if the SE system is entirely working. It is also the case that the SE systems have far more faults than all the other systems so the likelihood of us having a fully functional SE system is very low. Most of the time that's optimisers at fault, but they are also by far the most unreliable inverters we use and their support service is vastly worse than suppliers like SMA. Shame we can't actually buy any SMA kit at the moment!
That is quite an estate! 😳 Thanks for taking the time to share this insight. It’ll help people a lot in their decision making 👍🏻 I learned a few things too!
I was sceptical when my installer suggested optimisers back in 2013 but now having the data for every panel (occasional shading depending on the time of year) each panel varies by quite a degree in terms of output even in non-shaded conditions (i.e. two adjacent panels in summer for example) - if it was a single string, the whole array would have been pulled down by the weakest panel and thus over the lifetime of the array this could well add up to 100s of kWh - in close to 10 years this is very apparent and so I’m glad I went with them - I’m squeezing every W out of each panel so they have paid for themselves in their gains from my calculations…each to their own however. That said, back in the FiT days, the upper limit for the highest rate was 4kWp so there wasn't as trivial as adding more panels - even then the added cost for the panels and mountings might outweigh the benefits of the optimisers/u-inverters imo Bit long winded but, I have data from the first 4 years - the install was intended as a bit of an 'experiment' as my installer was explaining the virtues of thin-film panels over mono-crysytalline - they can have better low light output and better peak performance but at the expense of being bigger panels (hence more cost to install) - I suggested we went 50/50 on the same roof and I share the data with him - 1.95kWp Solar Frontier and 2kWp of LG - the difference has been pretty self evident though the LGs actually perform marginally better in low light (slightly better yield on dark days), the SFs better in peak conditions due to the 'light soak' effect. Solar Frontier did a case study at the time (not sure if still on their site) though I calculated gains of around 4-5% for the same kWp (they claim 10%) By way of example, on a crappy day in January 2016 my best thin film managed 133Wh, the worst 65Wh, the LGs were 96Wh and 82Wh respectively. On a good sunny day in July same stat - SF 2.4kWh vs 2.2kWh and LG 1.72kWh vs 1.65kWh so there is variation between panels - similar to the performance of microprocessors where they are categorised for sale depending on bench testing - for the thin-films at least this is very apparent, the LGs are much closer but again over a lifetime, those few Wh add up - I want to harvest every electron I can and on balance between cost and material input for the optimisers, they seem to be doing their job! (as an aside, I noticed quickly that the SF panels wouldn't 'come online' until they reached around 10-12W of power versus the LGs which started at 2-3W - I shared the data with SE and they sent over a newer version of the optimisers that were on the thin films as they have a Vp higher than monos - that solved the 'low light' problem as they all come on at around the same time now - it was a faff to replace but fortunately it's a bungalow so I just said to my installer that I'd do it myself rather than them get scaff back up etc)
one thing no one has touched on..at least in the extensive search on this topic that I have done.... the micro inverters are *VERY* useful if one has very limited room for panels and is running a 48v system. The micro inverters have a low voltage startup and being mounted onto each panel, can be used on most panels out there as the low voltage input range is fairly broad - so most panels have the voltage for them to work - then this AC is sent to an inverter like the Victron MultiPlus II and is used to charge the batteries connected to the victron inverter/s. If one tries to use a DC MPPT charge controller then one finds a "start up" voltage of 70-80+ volts - you cant get this from one panel. So if getting all you can out of *EACH* panel in a 3 or 4 panel setup that has shading issues through the day is *VERY* important to you, then a micro inverter is the answer. Note that what i have said above is for 48v battery systems. On a 48v battery system, even if you are willing to dedicate an DC MPPT controller per panel so that shading is dealt with, there are not many panels out there, that when used as a single panel system, produce enough voltage for the 48v DC MPPT controller to actually work. With 24v or 12v systems this is not a problem as a panel with 40v output has a high enough voltage to make a 24v MPPT do its thing. With a 48v system this problem is overcome as the micro inverter can accept just about any panels input voltage, convert it to AC and send it to the Hybrid inverter that then uses it to power its onboard battery charger. The added bonus is per panel monitoring.
@@GaryDoesSolar Gary, granted not many ppl would be looking for a microinverter to power 1 or 2 panels, but if one is doing just that (for example - on a sail boat) AND runs a 48vnom system then this is the best way. Its a very small niche to be honest but it does work.
An excellent presentation. In fact that’s one of the best presentations on the subject of partial shading that I’ve seen. I was aware of the bypass diodes, but hadn’t considered the impact on the larger array.
I think panels have evolved a little to include “half cut” cells. I think they run the bypass diodes up the middle of the panel, essentially doubling string number, and halving string length. It improves two attributes:
- better partial shading performance
- reduced diode hotspots, thereby improving panel life
That diode heat loss can be a real panel killer.
I did my own shading tests, which I think is in my Spring/June video this year. The direction in which shading is uncovered has a big impact on performance.
Coming from you, Anthony - that's praise indeed! Thank you. I might do a follow up on shading when I've collected enough feedback etc. and I'll be sure to include half-cut cells :-)
And I remember your shading tests - I can't wait to be my own setup installed in January to do some of my own (I'll have relatively easy access to the panels as I have a number of Velux windows on my roof). I've had a bit of a nightmare with my solar journey, which started back in March!
Let me know if you're interested to do something together on TH-cam at any time - I'd be game on for that.
Agreed, well presented. I’m breathing a sigh of relief knowing that I did do the right thing putting Enphase on my second array ( split across SE and SW facing roofs with chimneys ) Thanks
Direction of shade encroachment is indeed important. Most PV modules are wired as Gary illustrated so that the long edges each fall within one bypass diode zone. This is good for commercial ground mounted arrays facing South and with modules racked in landscape orientation. In that way the shade from the next most southern rack activates the minimum number of bypass diodes
how many strings can you break an array into? it seems like more wiring would be cheaper than optimisers or micro inverters, but there is a reason there are so many panels to a string and then the strings are in parallel; what are the limits?
Hi Scott, so it depends on your inverter. Most inverters only support two strings, but some can support three (or more). For each string, there is a minimum voltage level requirement before generation starts, so ideally, you want a lot of panels on each string to achieve that minimum requirement for longer in the day, especially if it’s cloudy.
There is an upper limit on the voltage (and also current) which will be different for each inverter manufacturer.
Gary, it is always such a pleasure to get the alert that you have a new video out.
Hi Nick - your comment has made my day! 😀 thank you!
My next video will be a very short one talking about the difference between kW and kWh,…. and maybe a bit about voltage and current in there too - all using the water analogy 👍🏻
Hi Gary [- Truly EXCELLENT video - concentrating on technical detail on how panels work and the effect of bypass diodes. As a professionally qualified electricaland electronics engineer- I think the solar trade in general needs far more of this excellent level of instruction. ( Sadly lacking -you only need to read some of the forums to see how poorly solar power is understood,
Having taken many so called "solar installer courses" from well known manufacturers - this video mostly stands head and shoulders above those - in terms of accurate well presented technical detail - not so such as to baffle people - but more than enough to understand properly what is going on
Excellent !
Thank you, Eric - that's praise indeed!
I'll keep working on new videos :-)
indeed Eric!
What I have found with my own testing is don't buy normal panels, buy half-cell split panels, or BF panels, as they don't souther nearly as much from shading, and even on an overcast day they produce nearly as much power as my 2 year old LG panels do in full sun, and they have expanded my day by almost 2 hours. Thanks for this video, I found it very helpful. Subed.
Sounds like great advice!
Bifacial panels are less vulnerable to shading? Why is that?
Great Job Gary!
Your channel is probably the best source of technical information about solar and battery systems on TH-cam right now, Gary. Many thanks for making such thorough and clear videos, I've learnt a lot from them.
Thanks Tim & Kat - that’s really kind of you to say 😀 When I looked into Solar for my own house, it was a real minefield of information and misinformation, so I thought I’d try to save everyone some time. Of course, once you release one video you kind of get hooked and spend countless hours putting together more 🤣🤣 Btw, I watched all your videos over the past few months. And am totally jealous of the 30% gas one - wow - and 1/3 million views and counting! 😳👍🏻 Keep up the great work!
@@GaryDoesSolar well, the time is very well spent, your video production quality is off the charts. I find it very amusing that you've been watching our videos in return. Ours are definitely a lot more rough and ready! It's funny, that first gas saving video was sort of intended for family and friends but then it went exponential which came as a bit of a shock. It turned out to be a double edged sword though as although it allowed us to join the TH-cam partner programme within two weeks it also came with a huge number of comments, which was a bit overwhelming. Most were very positive but a non-trivial number accused me of spreading misleading and dangerous information and even that I was going to kill people with my bad advice! It didn't matter that I got that advice from the Heat Geek channel and it was all perfectly accurate, some people still thought I shouldn't be giving advice if I wasn't a professional heating engineer. Oh well. I turned off the comments in the end and immediately felt a lot better! The internet is a funny thing, for sure. Our more recent videos are definitely a lot less controversial, thankfully. I look forward to whatever subject you tackle in your next video with great interest.
Thanks - that’s very kind of you to say. I’m certainly learning as I go. I need to improve my audio equipment as it’s different on and off camera. All the animations are done in (would you believe) Microsoft PowerPoint!
Sorry to hear you were getting some adverse comments. This is certainly one of the hazards of publicising any kind of content - and yeah, with the reach you got with that video, the level of comments (across the spectrum) was always going to be high 🤣
I’m still able to respond to each comment, but if the channel grows further, I know I won’t be able to. What’s great is that the comments give me ideas for future videos - the shading topic is a great example as in an earlier video I said something about shading that turned out to be a complete myth! Lol
What I like about your videos is that you’re highly relatable for everyone watching. And the fact that it’s “rough and ready” just adds to that. All the best with your channel. And I should be releasing a couple more videos soon (I’ve a back list of bay least 10 ideas so far - crikey! Just wish I had more time to actually make them!)
@@GaryDoesSolar PowerPoint! That's amazing, I never would have guessed. They're very effective, I have to say. Do you create the actual graphics yourself too? And I'd say your audio is fine, the difference between on and off camera is very marginal and hardly noticeable unless you're listening out for it.
By the way, if you ever need to do any 3D models or animations give me a shout, I've got some experience with that sort of thing (do a Google search for Stone Baked Games, my other side project). Something I'm planning on doing at some point is creating a sort of 3D visualisation tool of a house with solar panels and adding a (reasonably) physically correct day/night cycle that can be varied by day of the year, so that folks could see the angle of the light landing on their panels at different times. I've worked out the maths, I just need to sit down and build the actual project! In the mean time I've been using the on-line tool you suggested in one of your previous videos, which is very handy.
I also try to respond to all the comments I get (well, most of them) and at the moment it's just about manageable. But as you say, if the channel keeps growing that might become increasingly difficult. Thankfully the more recent videos have been almost exclusively positive, which I'm glad about.
I'm glad you like our videos. I was hoping that they would appeal to some people at least and that does seem to be the case, thankfully. Like you I have ideas for loads more, and for every video I publish I get ideas for another five (often from what people say in the comments!). Keep it up, you're doing good work that I'm sure helps a lot of people, myself included!
Hi Tim, thanks - yeah I create all the graphics myself too - again in PPT - but now I’ve seen what you’re doing with SBG, I’m clearly an amateur!! And funny that I saw the sphinx and pyramids in the sunbeam trailer as I’m in Egypt just now! 😀
I like your 3D solar utility idea and I’d of course be happy to promote such on my channel in due course if you’d like 👍🏻
Best video I've seen discussing this topic. Well done.
Hi David, that's praise indeed - thank you! :-)
good video. When we set up our solar company, we had two systems installed. one partially shaded with microinverters, one with a string system also with shade. We demonstrate exactly what you are showing, but live in real life situations on our own home. Hearing from clients who have upgraded older string systems to Tigo and EnPhase is a real joy.
Thanks for watching my videos and taking time to comment. I’ll be doing a follow up on the shading one, and it sounds like you’ve great insight! If there’s anything you’d like me to cover in that, just let me know 👍🏻 All the best with your company! 😀
Thanks for this, I saw the NRG Solar video, but it just raised more questions. It's all much clearer after you explained how the bypass diodes work.
You're most welcome, Dominic. I'm really happy to hear this feedback :-)
Quite a good video. I'll add a few other points that need to be considered:
* When designing a string without optimizers, make sure that there is plenty of voltage margin verses the optimal 'operating' MPPT range of the inverter. For example, if the inverter's optimal MPPT range is 300-500V, you don't want the total operating voltage of the string to be anywhere near 300V. You want it to be higher so partial shading does not reduce the voltage to the point where it leaves the MPPTs operating range. Of course you also have to make sure that the string's open-circuit voltage does not exceed the inverter's maximum voltage (for an inverter like this, typically 600V). So in this example, having the nominal operating voltage be, say, around 450V, would be ideal.
* Not all MPPT controllers are the same. When partial shading occurs, it changes the voltage-current curve that the MPPT controller sees. Sometimes the partial shading can cause a 'double peak' on the curve where one peak produces far more power than the other. If the MPPT controller fixates on the wrong peak, system performance can degrade well beyond what it should. So, for example, SMA's high voltage string inverters will do a periodic voltage sweep (usually every few minutes) to make sure that the MPPT is servo'd on the correct peak.
* In variable shading conditions... for example, foliage on a windy day, the MPPT point may move around more quickly than the MPPT can track, resulting in additional performance loss. Optimizers and micro-inverters are able to track these quickly-changing conditions far more quickly than whole-string MPPTs can. But in most cases, such effects are minor anyhow.
* People often make the mistake of paralleling multiple strings into a single MPPT. This results in far worse losses under partial shading conditions because any shade will cause the combined MPPT point to be non-optimal for BOTH strings. Thus, when designing a string system, always be sure to give each string its own MPPT and do not use paralleling (i.e. don't use a solar combiner box to parallel 2+ strings together). In modern day, it is really easy to dedicate one MPPT to each string, but older string inverters often had only one real MPPT controller.
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* Also, note that micro-inverters have the additional problem of back-hauling 240VAC instead of 400VDC, which means either (a) higher losses on the return wires or (b) requires lower-gauge (thicker) copper wires to backhaul the same amount of power.
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The bypass diodes are typically schottky diodes, each with a 0.3V volt drop when operating. Solar panels typically have three such diodes so if a panel is mostly shaded you not only lose the power from that panel, the string as a whole would also lose another 1V on top of that (per mostly-shaded panel).
Bypass diodes basically allow current to flow one way with a voltage drop of 0.3V to 0.7V. The solar panel itself develops a voltage across the panel which puts the bypass diode into reverse bias, which basically turns off the bypass diode. When shading occurs, the open-circuit voltage of the shaded panel is STILL LIKELY TO BE VERY HIGH, far more than 1V. However, the load on the panel (in shaded conditions) quickly drops this voltage as the panel is unable to support the current the other panels are generating, which takes the voltage below 1V and essentially turns on the diode, allowing it to conduct the other panel's current.
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So, generally speaking, it almost never makes any sense to use optimizers or micro-inverters, but one must still be a little careful when designing the string system to avoid the pitfalls mentioned above. The only situation where micro-inverters or optimizers make sense are in quickly-changing shading conditions because their individual MPPTs can react more quickly to the changing conditions. But that's it. I definitely prefer high-voltage strings over optimizers or micro-inverters.
-Matt
Wow - this is great insight! Thanks for taking the time to share with me. I'm considering a follow-up video on shading in a couple of month's time - and if it's ok with you, I'll try to include this insight (with credit given of course).
Great analysis. Maximizing the MPPT voltage is the key it seems, which means longer (i.e. higher voltage) strings are better. This also has the effect of extending the operating (time) window of the system (i.e. inverter on/off) closer to the peaks of consumption (i.e. morning and afternoon) so producing more useful output. Optimisers actually reduce the operating time window by reducing the string voltage slightly (thus resulting in later 'inverter on' and earlier 'inverter off' times), even when completely unshaded. Bit of a chocolate teapot IMO.
As far as I know there is only one micro inverter producer with true 400V micro inverters, AP Systems manufactures them.
Losses are higher with 400VDC compared to 240VAC no? Transmission line theory
@@whirled_peas Didi you get that backwards? The higher the voltage, the lower the losses, not the other way around. Losses are governed by P = I^2 * R (power = current squared times resistance). For voltage and current, transmitted power is P = I * V.
So for the same power transmitted, the higher the voltage, the lower the current on the wire. But losses scale to the square of the current so if you hold power the same and cut the voltage in half, losses will increase by 4 times.
For 400VDC vs 240VAC, the 400VDC line will 60% lower losses along the wires.
Of course it depends which country you live in. In some countries the utility connection to the house might be higher. But in most it hovers around the 200-240VAC range.
This is also why advertised efficiencies for micro-inverters and optimizers are usually somewhat disingenuous. For micro-inverters it is because they don't count the higher losses on the back-haul. And for optimizers it is because you still have to add-in the losses from the inverter that the optimizers are tied into (thus going through an additional conversion).
-Matt
I did a 2 panel test in series hooked up to a Bouge RV MPPT. Both panels getting full sun I covered one with a blanket. It took the watts to near zero for about 20 seconds but then the mppt adapted and gave about half of the 2 panel wattage. I think the whole panel has a bypass diode too that keeps one shaded from taking out the whole array.
Two panels in Parallel reacted to one fully shaded panel a lot faster almost immediately halving without going to zero for 20+ seconds. This convinced me that parallel is best for small RV 12v systems. You never know when you will turn and have shade across a panel. Losing 20-30 seconds of power everytime would add up. I also saw an increase in heat for the mppt controller with the series due to higher voltage having to be downstepped to 14.4v. However Series is a must for higher voltage battery systems (24v or higher) or you can use higher wattage panels as an option.
Thanks for sharing the results of these experiments! :-)
Quite frankly this is exactly what I have been looking for. Excellent presentation, and excellent communication. Having had solar for three weeks now, no micro inverters and the potential of chimney shading, this video has totally relaxed my worry about not asking for micro inverters. Thanks Garry - you have a new subscriber!
Thanks Barnaby - much appreciated! Glad to have put your mind at rest 👍🏻
@@GaryDoesSolar same situation here. I'm glad I've not performed a costly installation of optimisers on my 7 year old system. As you point out, the extra complexity increases your chances of failure and the benifits while there are not so big as to justify the cost.
Also, very nicely paced clear explanation with good illustrations.
Thanks Miles 😀 I’ll try my best to sustain this with my planned future videos 👍🏻
There are other reasons you would want to go with solar edge optimisers, #1 being the ability to oversize your panels and get access to dc power to charge battery or ev. Absolute game changer that your string inverters cannot entertain unfortunately
Excellent video, thank you. I was fretting about cable shading on my newly installed array, and couldn't understand why my panels were still generating when some of the stuff I'd read said they wouldn't. This has explained it in simple to understand language. Thank you.
You’re most welcome. Glad to have helped you in your solar journey! All the best for the future 👍🏻 😀
As having no experience in this field you’re videos have given me a better insight to what I need to know before I make a final decision on what to install,I wish to thank you for making it a lot easier to ask the relevant questions,excellent videos
Great to have been able to help out, Michael - thanks! :-)
Really appreciate the hard work and depth of information you provide in your videos. An invaluable source of knowledge, thank you.
It is my pleasure, Paul - yeah, hard work - but it's great to hear from people, saying my videos are helping them out :-)
Takk!
Thank you Magnar - that is very kind of you! ❤️
I've just read through most of the comments on this excellent presentation/video. There is really very little I could add. Extremely informative, challenging & clarifying supplier based information; excellent graphics. I suppose in summary, I feel in safe hands, without a hidden agenda. Thanks very much 🙏
Wow - thanks, Nic. That's very kind of you to say. I'll try to keep up the level of quality :-)
@@GaryDoesSolar You started out with a very high bar 😉
That was is a fantastic video. I have just been quoted for 3 strings, 4,4,6. One of the 4 will be shaded by a gable over time and they quoted optimisers for them. This makes sense no. I would imagine they will go from the simple aerial apology to the chimney over the day. This has given me more confidence in the company I have chosen. They have quoted them for a good reason and didn’t try and stitch me up by only adding them to the string that needs them. On to your next video now
Hi Michael, thanks for the kind words! :-) And really great that my video has been useful to you in making your decisions around solar. All the best with your solar journey!
Very informative, thank you. If we ignore reliability of the bypass diodes for a moment, it looks like only part shading that does not trigger the bypass diodes is an issue in terms of generation (overall the system generating less than it actually could so to speak.)
A quick search online suggests that bypass diodes can/do fail, and avoiding unnecessary load on them might be beneficial. In which case optimisers or micro inverters might have value in terms of long term maintenance/reliability, quite aside from slight increases in generation. HOWEVER, I am an amateur and quick searches online by amateurs often lead to mistaken beliefs…
I have a house with quite severe local shading on much of the roof, that varies through the day and seasons, so have a more complex situation than anyone with no local shading issues. My feel at the moment is that I will be using optimisers or micro inverters.
Thanks Glenn - I agree with your analysis. And if my situation was similar to yours, I'd be looking at having optimisers too.
As usual another extremely informative and useful video, I suspect it could save me a packet when we finally "take the plunge" early next year.
However I suspect I'll be rewatching all of your videos before we make a final commitment .
Thanks again Gary.
Thanks - that's so great to hear I've been of help to you :-) Good luck with your solar journey!
Excellent explanation. Best video on TH-cam explaining how they work and the pros and cons.
Thank you Dominic - that means a lot to me! 😀👍🏻
Best and easyest to understand video about this topic.
I've just subscribed.
Thank you for your work 👍
That’s praise indeed! Thank you, Alex 😀
Great video. I might have added that the situation described applies to an array of identical panels mounted in essentially the same place which is probably the case for most new installations..
Thanks, and agreed 👍🏻
Without a doubt, the best explained series of videos on solar PV! Thank you Gary
Hi John, that's praise indeed - thank you! And all the best! :-)
Very clear and informative. One advantage of microinverters is their ability to shut off power when the grid goes down. This is a safety issue and a requirement here in the US. If firemen need to go on the roof, series solar panels can present a dangerous HV DC.
Thanks Ken, for the kind words. And thanks also for highlighting this extra benefit. Although the videos on microinverters I've made up to now have been focussed on shading, I am going to make a video dedicated to microinverters, covering all of their benefits - I'll make sure to include this one :-)
I installed a new solar panel system 4 1/2 years ago. I live in the Desert Southwest of the USA where solar panels are a virtual necessity to prevent the power company draining my bank account. At the time I knew very little about the architecture of different systems. Like the vast majority of consumers I relied on contractors to recommend the best approach. Based on the recommendation of my installer, I ended up with a string array with a SolarEdge inverter/optimization. I’m lucky enough to have a large South facing roof with the one panel shadowed by a chimney that partially blocks sunlight in the morning. I’m a chagrined to learn that I could have saved a significant amount of money by eliminating the optimizers. I suspect that my installer, who is a very nice guy whom I trust, follows conventional wisdom in planning systems. I am going to share this video with him because I think he would be interested in lowering system costs allowing him to be much more competitive in pricing.
Hi Richard, I was lucky enough to visit your part of the world in the summer - had a great time there! And I can imagine why you were prompted to take action, to protect your bank account! :-)
@@GaryDoesSolar Hi Gary, I very much enjoyed your video have subscribed to your channel. Perhaps you visited my neck of the woods, Palm Springs, California. During the months of June through August we often have daily highs above 110°F. In the summer of 2021 we recorded two days at 123°F - which broke all previous records. On plus side, we have nice weather from October through May, with typical daily highs in the 70s F. Due to the purchase of an electric vehicle, I expanded my solar system from the original 12 kW to 15.5 kW. On a yearly basis I am at net zero electric consumption. I pay a few hundred dollars a year for grid use/maintenance/electric company profit. If I did not have solar, my electric bill would be around $5000 a year.
I would be interested in a future video on panel cleaning. In May of this year I had a professional cleaning that cost me $125. The panels had not been cleaned in over a year and were covered with a layer of dust as well as small debris here and there. Due to a severe drought there had been no rain for many months. Consequently I expected the cleaning to yield a significant improvement in production. However, reviewing my daily solar production (using the SolarEdge app) I could not see any change from the days leading up to the cleaning and after (all were sunny days with no clouds). So I wonder if panel cleaning is a waste of money - at least in terms of solar production? I would be interested in evidence you may have found regarding this question.
Hi Richard, my wife and I were on a self-drive holiday from LA over to Monument Valley and back (in a huge loop). We were within 100 miles of you! Now, I haven't looked into panel cleaning but I'll add it to my stack (which has about 20 items in it currently, so I've no idea when I will get round to it). Wow - $5K a year is some saving! 🙂
@@GaryDoesSolar Let me know if you do get around to doing a segment on cleaning. I’d be happy to share with you my experience as well as what I see as pros and cons.
Thanks Richard - I'll certainly do that 🙂
Fantastic video to help understand what's going on with string, micro, optimizers, etc. Thank you!
That's great feedback to receive, Jean-Marc - thank you! :-)
Nice explanation and definitely food for thought when deciding on the orientation of the panel based on likely hood of shading. If a wall or hedge is likely to shade the bottom of the panel late in the day it would make sense to have the panel in landscape orientation so only one string is bypassed and not all of them.
Hi Peter, totally agree! 👍🏻
Thanks Gary. This video is a model of clarity.
I have recently been mulling over the question of optimisers but, aside from generic 'marketing-speak', I had found very little in the way of hard information.
My gut feeling was that, for my installation, optimisers would offer little benefit and your helpful video has backed this up and saved me quite a bit of cash 😀.
Thanks for the kind words, John - and great to hear that I've been able to help you work through some of the decisions you have to make.
Well explained, thanks from all of us and great initiatives
You’re most welcome Nilesh 😀
Our panels were installed 12 years ago and our installer went to the trouble of reducing the height of the top of our soil pipe and resiting our TV aerial. This means that our panels can never be shaded. Your video has explained why that was excellent practice. We were offered Solar Edge optimisers but neither our installer nor the manufacturer’s documentation could not explain what they did and why we would need them. I’m glad we didn’t buy them as you have explained why they would have been of little benefit with our installation.
Thanks for sharing this, Trevor. I think others will be in a similar situation to you, and this will help them in their decision making :-)
The optimisers also provide arc fault detection, so fire protection and only provide 1V per panel open circuit so you can't get a fatal DC shock, you can also see each panel signals it's operating volts & amps on the Solaredge app, all besides each panel is doing its own mppt tracking.
Hi Jeff, see my other reply to you 👍🏻
@@GaryDoesSolar Thanks Gary Cheers
Another method explained to help deal with this problem is to wire more parallel strings with less pannles in series. Not always ideal but it does work.
Very clear presentation Gary. Well done. Subscribed
Thank you for subscribing - that gives me the drive to keep going! :-)
Thank you - terrific explanations and perfectly accompanied by the simple graphics. You have a new subscriber.
Cheers Malk - that's fantastic feedback, and it's great to hear that you're finding my videos useful :-)
Hi Gary,
As everyone else has said, this is another brilliant video - perhaps the best yet. The fact that you are very even-handed means, as you say, viewers can (and should!) make up their own minds on the subject.
I've just placed an order for a 16-panel (8/8 east/west array)/5kWh battery system. At this time of year, we will have heavy shading on the west array (from about 2.30pm until about 5pm) from a large oak tree in a neighbouring garden.
I've asked for Tigo optimisers on all of the west panels. We will have some shading on four of the east panels during the morning from a chimney. After some thought, I've decided to add optimisers to those four affected panels as well. I'm in discussion with Tigo at the moment about whether the Tigo Access Point (TAP) on the west array will be able to manage the additional four east panels. (The TAP connects to each optimiser by WiFi and is connected to the control gateway by a cable).
When I started to watch your video, I wondered whether I'd specification the optimisers unnecessarily, but by the end my opinion is that for my situation I have made the right decision.
Just a note on the point about costs: I've done a quick search for Tigo optimisers and the CCA (gateway) & TAP are available for about £60 & £400 respectively. Not an inconsiderable overall expense, but one which should, in my case, have a reasonably quick payback (I hope!).
Hi Phil - thanks for taking the time to comment in detail about your own situation. Yeah, I agree - optimisers are a good solution for you - and I would have taken the same approach. I'd love to hear how it all goes! :-)
Thank you. A very timely video for me as I'm in the process of comparing various quotes at present. I have tree shading issues so have been querying why optimisers are in/excluded from various quotes and why some quotes are only including partially optimised Tigo solutions. This is probably as clear an explanation of all the regular systems as I've seen (several compare Enphase and SolarEdge but very few include Tigo in the mix, which is what most companies are using in their quotations).
Keep up the great work.
Thanks very much for the kind words - yeah, it's a real minefield out there, and hopefully, I'll continue to be able to demystify solar in my future videos :-)
@@GaryDoesSolar The good news is that I'm not yet an Octopus customer, so will definitely use your referral code when I'm eventually able to make the switch (not just for this video, but the entire series to date, which has been excellent). Not sure if you're aware, but they're currently closed to new customers until Octopus find a way to make them compatible with the Govt Energy Support Payments, as there's currently no way to include these on fixed rate tariffs, which is what the Go and Agile tariff rates are.
It's very obvious how much work goes into these videos, so being able to use an affiliate code like this is at least a way to show support.
That would be very much appreciated, @@RiffMan117 - thank you! I’m using really basic equipment to make the videos (would you believe all the animations are in PowerPoint?!) My audio is all over the place, so I’d be using referral monies to buy better equipment 😀👍🏻
Great video, Gary. The time and care you clearly take to produce such professional presentations is definitely to your credit (not entirely sure about the start and end music, but hey that's personal taste!)
Hi Chas, thanks very much for taking the time to tell me this - it really means a lot.
I agree about the music - it's a bit tacky and I'll change it before long! :-)
Chas Winder: I agree, good comment.
Another fantastic video thanks Gary! Your graphics and commentary is superb. Greetings from South Africa.
Hey Andrew - thanks for the great feedback :-) Hope all is well with you!
Super presentation love the voice tone + explanations !!! BRAVO
Thanks again! :-)
Thank you Garry, the way you explain and present it is just invaluable! We need more heroes like you on TH-cam! 👍🏻
Hi Roberto - you’re far too kind, but thank you 🙏 😊 I’ll keep the videos coming…
Great video.
We have optimizers and I am quite content with them. We have 92 panels on our apartment building. We have an east--west orientation with a raised edge around the flat roof and a chimney in the center. You can follow the output of each panel through an app and usually there are significant differences. If you have panels in different orientations, you have to make either separate strings, each with their own inverter or use optimizers/micro inverters. Micro inverters make sense if you don't have a large number of panels. It's not only about direct sunlight shading. In clouded weather (diffused light) all panels are affected differently by sources of shade and no cell will have 100% shading. Also, dirt on panels can reduce the output of some cells more than others. Long term if we have to replace some panels by non-identical ones, that will not give us any issues.
Agreed - having the ability to individually monitor a large array of panels is a great benefit to have! I'll cover some of the points you make here in a follow-up video I'm making, especially about non-identical panel replacement... thanks!
You forgot that you can make multiple strings with a main Inverter that support 1 ~ 4 string groups. Or use multiple smaller inverters (given that you have 92 panels) that each take 1 or 2 strings, and output in parallel.
The problem with micro inverters as i see it, they are exposed to potential hot temperatures, constantly with no cooling. That will affect them, despite the claimed 25 years warranty, vs a larger inverter that has active cooling to keep everything nice and cool. Take it from somebody in the IT business, there is a reason why datacenters have AC, and servers are stacked with loud fans. Electronics , and yes, that micro inverter has electronics in it, will degrade faster. And wait when one or more dies and you want or need to replace it. Its one thing on a apartment building with easy access but normal homes where you may need to remove a bunch of panels to access the issue panels.
@@benjiro8793 We have optimizers, which have less electronics in it than microinverters. Our rooftop has good accessibility for replacing broken optimizers. Multiple string groups requires more cables, which is significant, because the inverter is in the basement. We may not have the most economical solution, but I am content with it. Electricity production is above expectations.
Brilliant content as usual Gary. This is the true spirit of the internet.
Hi Jamie, thanks - that means a lot! :-)
Good video and well explained, one that I can point customers to!! been on about this for years, in these situations we parallel connect if some of the array will be shaded, we also combine series and parallel connections. Keep up the good work
Thank you so much! Yes, please feel free to share my videos with your customers. My next one will be explaining all the energy terms: kW, kWh, voltage, current, single phase, 3-phase, frequency etc.
In Australia it is possible to get Enphase micro-inverters at only 10% more than a string inverter. One of the most important benefits not listed here is the increased reliability and longevity of micro-inverters; our local supplier recently switched to offering only Enphase micro-inverters for that very reason.
There are also significant benefits for PV installation companies in terms of managing and storing stock.
Having inspected several houses and businesses with non functioning solar systems, I believe the improved monitoring from micro-inverters is well worth that extra investment.
Thanks Chris - good insight here 👍🏻 And great to here the pricing differential is lessening
@@GaryDoesSolar Enphase IQ8 microinverter has a 1/500000 failure rate and will function accordingly for 25 years, longer of course but that is the limit of the warranty, works when the grid is down without the need for a battery. The options focus on in this video will have to be replaced at least once, possibly twice during the life of the array. Those are undisputed facts and serious considerations. The solar industry is pushing for a module life span of 50 years, None of the tech featured is capable of such a feat. String will die a natural death, the future demands innovation. Ultimately customer service is the reason Enphase is number one in the USA and hyper-growing in Europe.
@@s.lionelmcauley4455 Thanks for this extra detail - you've given me an idea for a future video... 👍
Excellent presentation. Nice and simple: the way true understanding always is.
Hi Doug - thanks for the great feedback! 😀👍🏻
Excellent and so very scientific. Many thanks Gary!
You're very welcome, Andre - glad you liked the video :-)
This is helpful. Seems to me that in most cases it's far better to simply buy more panels (as long as they fit) for a roof, rather than optimizers.
Thanks Don - I was careful not to draw firm conclusions one way or another. But I did want to get the point across that any improvements with optimisers are only marginal. If I had shading on my roof, I would like get optimisers for the affected panels, even just for the monitoring.
@@GaryDoesSolar Hi Gary. Thank you so much; these are fantastic videos which are so much easier to understand than just reading manufacturer's literature. I do have a question/observation. I've watched your earlier video 'How to choose SOLAR wisely and avoid costly mistakes' where you explain what each component does in a SOLAR system i.e. Solar panel, Invertor and batteries. In the Solar panel section, you mention that shading one panel will adversely impact all the solar panels in the series which suggests using optimizers and/or microinvertors is the only solution to reduce the impact of shading. However, your video 'Solar panels shading : Are optimizers and microinvertors worth it' you clearly explain that electronic protection measures are in place by having the bypass diode added to each array leg suggesting that optimizers and microinvertors are probably not worth the investment as the bypass diodes do a great job. Also, the cost of replacing the optimizer could be high for the reasons you explain. Maybe it's just me but I felt the videos slightly contradicted each other in the Solar panel sections. Let me know your views. Keep up the great work. Cheers
Misses out a lot about optimisers here.
The string number lengths can be much longer, meaning that much more often you can have just one string down to the inverter.
You can also parallel different length/orientation strings together (some conditions apply)
Also orientation of panels in the string doesn't matter so much due to individual mppt.
Open circuit voltage is only 1V per panel giving both panel signalling to an app for each panel's parameter indication and inherent arc fault fire protection.
Hi David, apologies - I thought I had replied to your comment already, but I see it’s not there. You’re right - on the earlier video I bought into the general perception that shading on one panel would affect all the other panels in the same string. Upon receiving a few comments for that video talking about bypass diodes, I decided to do some research myself, which concluded in the later video. It’s not really possible to modify videos once published but you can place correction markers, which I did. They may not always be displayed though depending on the device/app being used to view the video. Thanks for the kind words regarding my videos - much appreciated 👍🏻 😀
Hi Jeff, the features you describe are more advanced and I didn’t want to overwhelm the audience with what is essentially an introductory video into Solar PV shading. I’m now making a follow-up video though and will incorporate some of these into that. Thanks 🙏
Thank you very much indeed Gary; really well made, clear, easy to understand, I’m formative video.
You're most welcome, Richard :-)
A very good quality presentation.
It might be worth checking the minimum operating voltage of the string inverter, as this may come into play if the shading is across several panels stops it from operating all together. If you have dramatic shading, like I do on my garage and only space for 6 panels, then Enphase IQ7+ microinverters are the only real option.
There is also something called sub-panel optimisation where by you can replace the 3 bypass diodes with a small circuit that will optimise each of the 3 strings of cells. These were in the form of the Jinko Cheetah Maxim optimised panels - which I believe are now obsolete. It is a pity they did not continue this idea with more panels. So I am looking at building some of the modules to retro-fit to a test panel, the IC that forms the heart of this is the Maxim MAX20800. This involves removing the silicon potting compound and diodes and fitting a small PCB and re-potting it to waterproof it and conduct any heat away.
Its worth also mentioning that the panels do not need to face the sun to produce power, as I have mounted a panel on the west vertical wall of my garage to take advantage of the setting summer sun, but even in the autumn/winter when the panel does not get any direct sunlight, I can still see perhaps 160Whr on a part sunny/cloudy day with the sun bouncing off the clouds and 60Whr on a clear blue sky sunny day.
Hi Rob, thanks for the kind words. And thanks also for this detailed comment. Lots of information in there for me to work through, especially as I'll be making a follow-up video on the shading topic soon... I love it that you're not frightened to get stuck in on the bypass diode circuitry! :-)
Hi Gary. Thank you so much; these are fantastic videos which are so much easier to understand than just reading manufacturer's literature. I do have a question/observation. I've watched your earlier video 'How to choose SOLAR wisely and avoid costly mistakes' where you explain what each component does in a SOLAR system i.e., Solar panel, Invertor and batteries. In the Solar panel section, you mention that shading one panel will adversely impact all the solar panels in the series which suggests using optimizers and/or microinverters is the only solution to reduce the impact of shading. However, your video 'Solar panels shading: Are optimizers and microinverters worth it' you clearly explain that electronic protection measures are in place by having the bypass diode added to each array leg suggesting that optimizers and microinverters are probably not worth the investment as the bypass diodes do a great job. Also, the cost of replacing the optimizer could be high for the reasons you explain. Maybe it's just me but I felt the videos slightly contradicted each other in the Solar panel sections. Let me know your views. Keep up the great work. Cheers
Thanks David, for the kind words. Really great to hear you’re loving the videos 😀
Yes, you’re right. In the earlier video, I feel I was duped by marketing material and also many TH-cam videos that claimed shading on one panel would affect all the others. It was only when someone mentioned bypass diodes in the comments to that video, that I thought I should undertake my own research to get to the bottom of it all. And I’m glad I did!
Now, I added a correction to the first video but I guess it was not prominent enough - it should state “CORRECTION“ at the appropriate point in the video with a link to the later video…
This is the first video I've seen to clearly explain the pros and cons of optimisers.I assumed I needed them. I'm not sure the benefit of individual panel monitoring and a small improvement in efficiency can justify the cost.
Thanks David. I was quite surprised at the lack of pertinent information available on the topic myself. Yeah, the benefits are not exactly stand-out.
Not sure Tigo even works at all
Thanks
Thank you, John! Much appreciated :-) :-) :-)
Hi great video, I’ve some companies installing the optimisers in the loft ,by simply rooting the optimiser cable under the felt , so if any optimiser issues, being in the loft makes easy access and no need for scaffolding,
Thank you. And I quite like that idea! Hopefully, they'll ensure no chance of water leakage into the house though! :-)
@@GaryDoesSolar Hi yes they do use some kind of weatherproofing that’s actually designed for this type of installation
That's great to hear! Good luck with the install 🙂
Nice video, and well put together.
I'd add 1 more con to your list of optimizers
1. A constant 2% efficiency loss at the optimiser itself, regardless of shading or direct sunlight.
I feel that most PV systems do not require optimizers/micro Inverters, but they do have their place in more difficult roofs with unavoidable shading.
Good survey and design mitigates the need for optimizers in most cases in my opinion.
Thanks Euan, for the kind words and also the additional points. I’ll incorporate into my follow-up video on shading 👍🏻
Gary I send all my customers in 2 minds about shading to your video and encourage them to use your octopus referral code- thanks for your comprehensive research
Hi Aaron, that's so very kind of you to do that - thank you! I think some have signed up as well :-) You've very welcome regarding the video content. All the best!
Thank you!! Of many analyses I read and watched about this topic, you are the first to mention the difference between hard/intense shadow and diffuse shadow where the bypass diodes don't kick in. That's the missing link!
We've got two nearby buildings higher than our (southern) roof and their (hard) shadows wander across our roof during winter. But there aren't any high trees, cables etc. nearby. So if I understand correctly, the most that I need is a decent mpp tracker and a clever orientation of the modules (because building covers up the lowest meter or less off the roof traveling from one side to the other, the modules (~1.7m x ~1m) there should be installed horizontally), correct? Now I just have to find out whether 1mpp tracker is enough (all modules go on one side of the roof).
Thanks Thomas - great to have feedback like this. Now, if your solar panels are of the half-cell variety (see part two of my shading videos) then you could still mount those panels in portrait format on the bottom row. And assuming you're planning to use a string inverter with two strings, you could ensure that all the panels along the bottom are on the same string, which will help with tracking. Alternatively, you could look at having optimisers on the panels along the bottom row - but given these problems are only during winter, I'm not sure that this extra expense would be justified. Good luck with whatever you decide! :-)
@@GaryDoesSolar Thanks a lot for the helpful reply! Yes, half-cell, and yes, inverter with 2 strings (and 2 mpp trackers), but I am also thinking about extending the setup to the garage in the not-too-far future, so will ask my electricion if it makes sense to then go for an additional (smaller, 1-string) inverter or whatnot.
This is a really nice overview of what the optimisers can and can't do. How often is shading extreme enough to actually trigger the bypass diode? Shaded but not bypassed seems to be where optimisers would work best. Even though they add cost they should reduce the fault finding time if a panel goes bad and can allow you to have different panel angles and positions without multiple string inverters.
Thanks Andy - great to get feedback like this.
Now, I read that bypass diodes will typically kick in when they detect a 20% difference in current. And I agree, if my roof had shading, I'd likely put in optimisers on the shaded panels just for the monitoring capability.
It is very rare for a panel to go bad. The probability calculation is not in favour of oprimisers. Even with untriggered bypass diodes, the optimisers gain only
@@GaryDoesSolar the bypass diodes are Schottky diodes, and they block the current in reverse, and conduct when the is a potential on 0.1 V accross them in the forward direction. @ 10A, they will dissipate 1W of heat. This is a failure point of cheaper panels that use cheap under sized diodes. A 3 or 5w rated diode should be used to ensure longevity. The diode is simply a one way valve.
From Wikipedia Schottky diode page:
"...
Reverse current and discharge protection
Because of a Schottky diode's low forward voltage drop, less energy is wasted as heat, making them the most efficient choice for applications sensitive to efficiency. For instance, they are used in stand-alone ("off-grid") photovoltaic (PV) systems to prevent batteries from discharging through the solar panels at night, called "blocking diodes". They are also used in grid-connected systems with multiple strings connected in parallel, in order to prevent reverse current flowing from adjacent strings through shaded strings if the "bypass diodes"
Effectively, if there is shading and the panel or string becomes effectively open circuit, the rest of the string, eg 300v, easily pushes past the 0.1v required turn on voltage of the diode, and current then flows past, bypassing the open string. Simple and effective.
Best video yet Gary 👍
Thank you! This particular one took quite a while to put together! I need to try and get more efficient with the recording and editing - that's just as hard as getting the content together! Lol
Thx. Great.
Very clear and educational. I have been searching this and now the yt algorithm keeps popping up these vid s about string vs optimized panels.
This one is very good!
Thanks - it’s really hard to get traction on TH-cam as there are soooo many videos being produced all the time! Great to see that my videos are getting some exposure 😀😀👍🏻
A very informative video that helps to clarify the pros and cons.
You're most welcome - thanks for taking the time to comment :-)
Great information Gary, very clearly explained, thank you
You're most welcome - great to have feedback like this :-)
In addition to cons of optimizers (and microinverters) being cost and additional failure points, there is also lost efficiencies of having them in the system. For instance, the Tigo and Solar Edge optimizers are active devices which themselves consume power. So in a largely unshaded installation, the overall power output is typically greater without those parasitic device losses.
Hi Bill, a very good point. I'm hearing these devices use (lose) maybe 2% of the available power. I'd need to confirm that though...
I have to say that was a great video I had no idea that the solar panels with micro inverters had those bypass diodes which makes them much more immune to shading problems .
Thanks Roger 👍🏻 I’ve got a follow-up video on shading coming very soon… Hope you enjoy that too!
Very interesting and useful! Wish I had seen this before I had my system installed a coupe of years ago. I think the point about simplicity is very important. I just had one of the solaredge optimisers go and whilst solaredge sent a replacement for free it cost £150 + VAT to replace. (my installer has ceased trading - probably to wipe the slate clean - and it was just outside the 2 year insurance backed warranty) That's a big hit on the payback of a single panel, which is even worse when you consider the marginal benefit provided by the optimiser. solaredge optimisers do not seem to be that reliable? My panels are on a single pitch of a bungalow to easy access. Seems anyone with a high roof and difficult access should seriously consider if optimisers are worth it
I was surprised that the optimiser can rescue nothing from a panel where the partial shading has tripped all the bypass diodes. Maybe we need to consider exactly how the shading will fall and select panels to minimise that issue? Do different panels have different diode orientation?
Sorry to hear about your bad experience with the failed optimiser. I agree, they provide only marginal benefit in many cases, against a high cost to fix in the event of failure. There doesn’t seem to be enough margin in the manufacturers’ products to allow for a better warranty payout :-(
Very clear and informative: thank you. I had understood that optimisers did have a downside of 'stealing' one or two percent of the power from a cell permanently. So that while they may help in complex shading scenarios, they do extract a price to do so. Is that your understanding too? Best wishes. Michael
Hi Michael, yeah, that’s my understanding too. I aim to cover this in a follow-up video I’m making 👍🏻
This is a must watch video. Thanks a lot.
You’re very welcome - thanks for taking the time to let me know 😀👍🏻
Wonderful. Great information clearly explained, thanks bud!
My pleasure Bob - thank you! :-)
Great presentation, thanks for sharing, when you run out of ideas this topic can be extended to half cut cells modules and having strings in parallel how this is being affected.
Having one bigger string or having 2 strings half the size in parallel.
Again thanks for sharing:)
Thanks George, and we are thinking like! I am planning a follow-up at some point to cover the topics you raise and also a few other things... :-)
Very clear explanation , thanks. What about panels in parallel ?
+1 for maybe looking at what happens with panels in parallel. As I understand it, this solves a lot of problems with shading in a series/string setup, but only if your inverter / charge controller works with the lower system voltage (due to the panels being in parallel rather than a series string)
Thanks Jamie. Certainly, parallel panels allows the current another route round in case of shading on one of the panels. I'm planning a follow-up video on shading in a couple of months and will try to cover this.
Very clear and detailed explanation. Thanks!
You're very welcome, Stijn :-)
Thanks again Gary- so much useful information!
Thank you for watching, Paul - I'll keep the videos coming :-)
Very informative. Thanks Gary
Thank you - this one took quite a while to put together!
@@GaryDoesSolar Yep it takes more energy and time than what we could see and think. Great job and thanks again.
Fantastic video and well explained and illustrated.
Thank you Morne! :-)
Good explanation and analysis of the pros and cons. Thank you.
Thanks John - that means a lot as I’m a big fan of your videos - you’re very calm and clear! 😀
@@GaryDoesSolar ah bless you. Thank you.
That is the best presentation of the pros and cons of optimization that I have seen. Thanks! SMA says they have a new MPPT routine for their string inverter that works as good as optimizers in some circumstances without the reduced reliability. Have you figured that one out yet?
You’re most welcome, Mark. It’s great to get feedback like this, as my aim is simply to demystify everything. Now, I didn’t know about the new SMA MPPT routine - I’ll check that out… 👍🏻
There are two more scenarios I can think of in which you can use optimizers:
- you can have one string with some pannels placed at different angle on the roof or facing different direction
- you can have pannels with different power output connected in one string
I know that these are not good scenarios and should be almost always avoided, however they are possible with optimizers.
Thanks for the insight 👍🏻 I could imagine a roof with three orientations but the inverter can only support 2 strings.
Not sure which products can ‘can cost the same as the panel’ but I know the basic Tigo is about £40. Interesting video though as my issue will be solid shadow from a chimney going right through an entire panel which suggests an optimiser will be pointless. Thanks for posting.
You're most welcome. Yeah, Tigo optimisers are quite cost-effective, but some of the others aren't :-/
I think your best option would be to avoid putting a panel within that area, BUT I know that is very easy to say in a comment without knowing the whys and wherefores.
Another very informative video - thanks very much.
Thanks Adrian - this one took quite a while to put together!
@@GaryDoesSolar I'm sure it did as you can tell by the graphics and references you found to back up your explanation and reasoning and what people don't understand is the time ot takes to find what you are after and then to cros check what you have fojnd to make sure that it is correct. This takes ages. People in general just see the presentation and just assume that it has been grabbed and don't realise that research takes an incredible amount of time. Probably due to a lot of people just taken a source at face value and don't cross check. No, it is a very informative video as your others have been btw.
Nice video, well presented. I do think you missed one aspect - in all your examples you are referencing a single serial string if panels.
I think that it's fairly common to have parallel strings with (passive) combiners driving into a single charge controller/invertor. If one string is shaded it's voltage will be reduced, compared to the other (parallel) strings. It would be interesting to see how this manifests - I suspect that you would loose all of the power production from that string.
It's also worth noting that if parallel strings are placed on different aspects of a roof that the same situation can occur... If at all possible panels should face same direction, or be wired on different charge controllers.
Thanks for the kind words. I'm getting quite a lot of interest in this particular video, and suggestions (including those you raise) for a follow-up video - so my plan is to work on that soon :-) I really appreciate you taking the time to comment
Thank you for an well presented (and correct) explanation of solar shading.
Thanks Tom - your comment is very much appreciated :-) I'm making a follow-up video on shading shortly...
Another awesome video Gary.👍👍. The only benefit as far as I can see is the ability to check how each panel is working. Might be useful for the photon geeks?
Have you seen the Australian TH-camr: Off Grid Garage he demonstrates Hyundai shingled panels with a voltmeter and fries his voltmeter entitled "Hyundai Shingled Solar Panels - 15% better than other solar panels?"
Thanks David. Very kind of you to say 😀 You’ve got me thinking about these shingled panels…. 👍🏻
Very professional. Thank you.
Hi Jen - that's very kind of you to say - thank you! :-)
Hi gary, fitted 4 TIgo optimizers to my string on 4 panels that get shading around 2-4 o'clock. Have noticed no improvement with using them, so will be selling them on ebay.
Thanks for sharing this Jon - it sounds like you've got an installation then added the optimisers to see if they would improve generation because of the shading, but in actual fact, there was no change. If so, this is better empirical evidence for folks to consider, and I hear so often from people who had optimisers fitted from the start, that they're doing the job... but how would they know?
And as you're talking about Tigo products, it looks like the company has some interesting problems to deal with - see this article on reddit: www.reddit.com/r/solar/comments/144j15k/tigo_ts4_modular_level_power_electronics_melt_down/
Thank you for your very good videos and they are very informative of what is best.
Cheers Dave - great to get feedback like this ❤️
Another brilliant video Gary. I look forward to seeing what you tackle next. I wonder if you'll get any feedback from SolarEdge/Tigo/Enphase?
Hi Tony - thanks very much. Now, I've not heard anything yet - and hoping they'll will see I've been objective and also have simply quoted their own materials. I'd certainly be happy to record a video with them if they wanted to extol the benefits of their products... :-)
I need to get me some bypass diodes. I always wondered what they were for, i thought it was to stop power flowing back into any potentially weaker panels during certain situations or if a problem arose in one of the panels.
I believe most, if not all, solar panels manufactured today have bypass diodes included as standard. Worth checking for your panels, certainly...
Just food for thought to consider cost benifit is the ease of system diagnostics with the panel level monitoring that solar edge and enphase offer apart from Sma and fronius. The average homeowner doesnt have the knowledge to know when something is off at the panel level (diode issue, multi cell degradation). Also the fact that that enphase is modular system for reduced production loss with any defective equipment. Ive installed and serviced thousands of site between all manufacturers. There alot more after the fact to consider rather than just the unfront ideology.
Hi Jarod, these are great points - thanks! I’ll make mention in a follow-up video I’m doing… 👍🏻
Very informative video. Thanks for that tip. I have 3 different solar power systems that I own. 2 on the RV's and one on our house. the house has the Enphase micro inverters and the RV's both have NPPT controllers. Only one of the RV's uses an inverter. On the one RV I have seen a low or no output situation, as the solar panels had not been cleaned in quite a while. I thought it very odd that with 800 watts of possible output that the controller showed only the low battery voltage. I think it was around 8V, not enough to power the inverter or even the LED interior lights. Now I understand why that happened. I have a video about my 3 systems posted, if you'd like to check it out. I'd be very interested in your evaluation of my 3 different systems. I guess now I have to go clean a few solar panels!
Hiya - I'm going to take a look at your videos! :-)
Hi Gary, very informative video thanks. I'm just in the process of designing a system at home and wondering if I needed optimisers. I'm still not 100% sure, can you clarify what your diagram shows at 16:45. If I have 2 panels out of a string of 6 that are not producing any current, without optimisers are the other panels still able to push current through the shaded panels? I thought if all the panel was shaded it would block the current.
Hi Kieron, great to hear you got a lot from my video 😀 So, in the video then: if there were no bypass diodes in the panels, any fully-shaded cells would completely block current flow in that panel and also for all the other panels connected in the same string. The bypass diodes essentially “detect” shaded cells then re-route (bypass) current around them - to the extent where if a whole panel is shaded, the three bypass diodes in the panel will simply bypass the current through themselves, avoiding all the cells in the panel completely. Hope this helps!
Thank you for that very useful information. Great video as always A++
You're most welcome - thanks for taking the time to comment :-)
The video was well explained. I have a better understanding now. Still I have some concerns. (Time frame 16.01, what if the panels which are shaded is only having optimisers, will it give the same result, how mppt works in this case.) Does the optimiser in a panel will help that specific panel to improve the power output.
Thanks for your kind words, Amrutha. Yes, if only the shaded panels had optimisers, the output would be just the same as all the panels having optimisers. Each optimiser acts only on the panel it is managing, and it will bypass current around the panel if it is not performing as well as the others.
Gary I am considering solar. I have a roof which faces directly SSE 150 deg. It has 0% shading. No adjacent roof lines or chimneys or power cables. Clear unobstructed views. Effective arc of sun say 90 - 210 deg . I live in Kent UK. I believe it could fit 12 panels. The only shading occurs via sun rise to the east and then suns transit to the west. Say summer the roof is Not in direct line of sight of the sun by 1800. Still day light but not direct. Would the solar system conclude that with no direct sunlight system shuts down or significantly reduces power, I think the latter? Also with 0% direct shading that micro inverters would be overkill and possibly optimisers are not required??? Your views would be appreciated. And yes I have subscribed and like. Regards Steve.
Hi Steve, great to hear you’re starting your solar journey! Now, I receive many questions about individual solar setups and specific needs, and while I’d love to respond to everyone personally, my time is unfortunately limited.
The good news is there are fantastic online communities, like this UK solar and battery group, where experienced members are more than happy to share free advice and support: facebook.com/groups/2197329430289466.
If you're based in the UK and looking for more personalised guidance, I also offer a "Chat with Gary" service. While it’s a paid option, it allows us to dive deeply into your unique situation and find the best solutions for you: garydoessolar.com/chatwithgary/.
I wish you all the best in your solar journey, and I hope you find the perfect solution for your needs!
This was incredibly useful thanks. Great to get the technical detail. Cheers.
You’re very welcome! Thanks for taking the time to comment 👍🏻 😀
Another great video. Informative and unbiased.
Thank you! I do pride myself on being as objective as I can 👍🏻
An excellent presentation!
Thank you! Part two on shading hopefully coming in the next couple of days….
Great video Gary!
Thanks Phil - this one took quite a while to put together!
@@GaryDoesSolar Yes, I can imagine that it was a lot of work. Excellent job Gary!
I manage about 10MW of rooftop solar across the UK. Of that about 20% is SolarEdge.
It is entirely fair to say the the SE systems do produce more than an equivalent string inverter system. It's in the order of 1-2% if the SE system is entirely working.
It is also the case that the SE systems have far more faults than all the other systems so the likelihood of us having a fully functional SE system is very low.
Most of the time that's optimisers at fault, but they are also by far the most unreliable inverters we use and their support service is vastly worse than suppliers like SMA. Shame we can't actually buy any SMA kit at the moment!
That is quite an estate! 😳 Thanks for taking the time to share this insight. It’ll help people a lot in their decision making 👍🏻 I learned a few things too!
I was sceptical when my installer suggested optimisers back in 2013 but now having the data for every panel (occasional shading depending on the time of year) each panel varies by quite a degree in terms of output even in non-shaded conditions (i.e. two adjacent panels in summer for example) - if it was a single string, the whole array would have been pulled down by the weakest panel and thus over the lifetime of the array this could well add up to 100s of kWh - in close to 10 years this is very apparent and so I’m glad I went with them - I’m squeezing every W out of each panel so they have paid for themselves in their gains from my calculations…each to their own however. That said, back in the FiT days, the upper limit for the highest rate was 4kWp so there wasn't as trivial as adding more panels - even then the added cost for the panels and mountings might outweigh the benefits of the optimisers/u-inverters imo
Bit long winded but, I have data from the first 4 years - the install was intended as a bit of an 'experiment' as my installer was explaining the virtues of thin-film panels over mono-crysytalline - they can have better low light output and better peak performance but at the expense of being bigger panels (hence more cost to install) - I suggested we went 50/50 on the same roof and I share the data with him - 1.95kWp Solar Frontier and 2kWp of LG - the difference has been pretty self evident though the LGs actually perform marginally better in low light (slightly better yield on dark days), the SFs better in peak conditions due to the 'light soak' effect. Solar Frontier did a case study at the time (not sure if still on their site) though I calculated gains of around 4-5% for the same kWp (they claim 10%)
By way of example, on a crappy day in January 2016 my best thin film managed 133Wh, the worst 65Wh, the LGs were 96Wh and 82Wh respectively. On a good sunny day in July same stat - SF 2.4kWh vs 2.2kWh and LG 1.72kWh vs 1.65kWh so there is variation between panels - similar to the performance of microprocessors where they are categorised for sale depending on bench testing - for the thin-films at least this is very apparent, the LGs are much closer but again over a lifetime, those few Wh add up - I want to harvest every electron I can and on balance between cost and material input for the optimisers, they seem to be doing their job! (as an aside, I noticed quickly that the SF panels wouldn't 'come online' until they reached around 10-12W of power versus the LGs which started at 2-3W - I shared the data with SE and they sent over a newer version of the optimisers that were on the thin films as they have a Vp higher than monos - that solved the 'low light' problem as they all come on at around the same time now - it was a faff to replace but fortunately it's a bungalow so I just said to my installer that I'd do it myself rather than them get scaff back up etc)
Thanks for taking the time to make this detailed comment. It's great to hear that it all worked it for you :-)
Really well explained. Great job.
Thank you! :-)
Very well done, Thx!
How big is the power consumption (loss) of the micro inverters?
Couldn't find anything in the Tigo datasheet?
That’s a good question! I don’t know the answer - it would have to be low however, otherwise it would negate any production increase 😳
Love the explanation...well presented.
Thank's John! :-)
one thing no one has touched on..at least in the extensive search on this topic that I have done.... the micro inverters are *VERY* useful if one has very limited room for panels and is running a 48v system. The micro inverters have a low voltage startup and being mounted onto each panel, can be used on most panels out there as the low voltage input range is fairly broad - so most panels have the voltage for them to work - then this AC is sent to an inverter like the Victron MultiPlus II and is used to charge the batteries connected to the victron inverter/s. If one tries to use a DC MPPT charge controller then one finds a "start up" voltage of 70-80+ volts - you cant get this from one panel. So if getting all you can out of *EACH* panel in a 3 or 4 panel setup that has shading issues through the day is *VERY* important to you, then a micro inverter is the answer. Note that what i have said above is for 48v battery systems. On a 48v battery system, even if you are willing to dedicate an DC MPPT controller per panel so that shading is dealt with, there are not many panels out there, that when used as a single panel system, produce enough voltage for the 48v DC MPPT controller to actually work. With 24v or 12v systems this is not a problem as a panel with 40v output has a high enough voltage to make a 24v MPPT do its thing. With a 48v system this problem is overcome as the micro inverter can accept just about any panels input voltage, convert it to AC and send it to the Hybrid inverter that then uses it to power its onboard battery charger. The added bonus is per panel monitoring.
Thanks for sharing this insight 👍🏻
@@GaryDoesSolar Gary, granted not many ppl would be looking for a microinverter to power 1 or 2 panels, but if one is doing just that (for example - on a sail boat) AND runs a 48vnom system then this is the best way. Its a very small niche to be honest but it does work.