Dear TH-cam Algorithm, I hope you read this. Recommend "Gary does solar" to everyone. As an electrical engineer, I am inspired by the concise, accurate and technically correct explanations with clear diagrams and explanations. Thank you!
You are absolutely correct about Solaredge optimisers. I have 16 panels installed in 2018 and 2 optimisers have already been replaced after they failed. Fortunately mine are easily accessible, so no big deal. Excellent explanations. Thanks.
"The Tigo Optimizers would not work unless they were connected to the internet" Thank you for that warning. When talking to my contractor on what I would like for an installation, I specified "No cloud services whatsoever". They were like "We might have to hack some stuff". Freaking wild. Cant even buy a brick. It has to be a spy brick.
Yeah, this is the world we seem to be living in now - everything is connected. I can hardly complain about it myself as a lot of my career is in the mobile industry where I developed the technology to do much of that. I get it though, that for many people, they prefer not to have devices around them connected - unless absolutely necessary :-/
I suspect that many installers aren't really keeping up with technology developments and simply have a few "recipies" that they choose from that they match against the house configuration and whatever kit they can get at the time. From what I read, if MCS had any real oversight of those they certify, there would be mandatory ongoing education and training to keep them up to date. I've yet to pull the trigger on a Solar PV/Battery system for my own house (NE/SW roofs with slight shading from chimney on NE roof), but I won't just be having whatever an installer throws at me. As it's my money and roof, I'll be having the kit *I* decide on. Another well researched video BTW. Looking forward to your next one ...
You're totally right, Tony - getting true value for money is hard these days, and certainly I've found that having knowledge up front makes a huge difference. Good luck when you pull that trigger... :-)
I have just had (for a week so far) a Tesla PW3 with 11x435W panels across 3 elevations. NE/ES/SW The installer put them on ONE string, with Tigo optimisers on every panel. I queried this, because the PW3 has 3xMPPT anyway, and surely optimising over a 270' arc is a bit of a stretch??? Having said that, so far I'm achieving the daily expectation for October in my region (7E, north west). It just makes you wonder if you can achieve more...
I just wanted to say thanks for your videos. It really helped me talking to the sales person. At least it made me feel I had a level of knowledge that I could ask the right questions. My 14 panels, and 2x 3.2 batteries and 3.6 Lux Hydrid inverter were installed last Wednesday. I can’t stop looking at the monitoring 😊. After you last videos, I checked and we have half cell panels. We have had a few hours of free power. This impressed me for winter. Thanks again. I will still continue to watch.
Thanks for the very kind words, Michael. And also, I really appreciate your “super thanks” - it’s a lot of work to make my videos and so this means a great deal to me 😀👍🏻 Sounds like everything went well with your installation and it’s performing well in the winter, so this sets the scene for even better performance over the next 6 months - all the best!
Absolutely fantastic series Gary. Informative, accurate and concise. I don't think there's a better channel out there explaining the practical considerations and implementation of solar panels out there. Well done!
Another brilliant video with eye-opening content, which totally reinforces parts of the learning matrix: "There are things, you know you don't know" & "Things you don't know, you don't know" Always an education and pleasure to watch. Thanks very much for the work and research put into these excellent videos 🙏
Thanks Nic - yeah, it always feels like I'm going down the rabbit hole every time I get into a topic! :-) But great to hear that you and others are getting a lot out of it! :-) I'll try to keep the channel interesting!
Thank you for a great and easy to understand content! I think you need to add some economical aspects: - optimizer cost about 55 EUR/per panel (without cost of labor) - they consume energy as well and it is about 2%, so this can put away the benefits - to be able to monitor individual panels, as mention their benefit, you need additional management box which cost you additional 250 EUR I think microinverters are better solution for smaller installations (do optimizer job and convert DC to AC and can be monitored individually without any additional HW) because you are very flexible (different orientation, no need to use "solar cables" for DC, just regular ones for AC) no need of central big inverter which cost from 1000 EUR and more. But at some point, if think only economically, they makes no sense because of the price, e.g. 10x 550 W panel needs 10 microinverters * 220 EUR = 2200 EUR instead of lets say 1500 EUR per central inverter.
Thanks for the extra insight. Now these videos were focussed on shading, but I plan on making a video on optimisers shortly, just to complete the picture on the dedicated microinverters video I made here: th-cam.com/video/q6t0AAi5Jws/w-d-xo.html
Your conclusions make a lot of sense. I could invest in a high quality, reliable hybrid inverter for considerably less than a micro inverter based system.
Thanks Kevin. Yeah, for management of most types of shading, the bypass diodes in your panels will do a good job in a string inverter system. If you have a lot of trees around, then optimisers and microinverters have some value there.
This is some incredibly useful information, thanks Gary. I have just placed an order for a solar PV system with battery storage and included 8 TIGO optimisers for the south array which will suffer from shading by a large oak tree. In the light of the information you have given, I have contacted my installers to remove the optimisers from my order. Keep up the good work.
Thanks Brian - very happy to have given you sufficient information so you could come to a decision on this. And good luck with the install when it comes!
Hi, Very interested in your decision to not to use TIGOs. I have just has a PV system installed with battery without any TIGOs. Thought installer might have computed estimate wrong as there is a small tree directly South which casts a shadow between 13.00 and 14.30. Trying to decide whether it makes financial sense to add TIgos. Received quotes of £3k for all 15 panels and £1k for 5 panels. So all very interesting. Have you any idea how much extra production you would have got with your 8 TIGOs. Thanks
Me neither, John! And you're very welcome! :-) A quick question, if I may: you did some thermal imaging in one of your recent videos, and as you're pretty expert in photography, what equipment did you use? Was it a standalone unit, or combined with some of your existing camera equipment? And have you ever analysed your arrays with it? Many thanks!
@@GaryDoesSolar I purchased a Hti HT-A1 standalone camera. I'm not sure they are still available new as it's fairly old now. I had not even thought of using it on my arrays until you covered it in this video, however I will be once we get some better weather.
Gary, your video is perfect! Explain everything very comprehensive way and I am really glad and appreciate you said a little bit ugly truth about reliability of system with optimizers... ...and microinverters as well. Well, everybody should know ALL pros and cons of the systems. Many installation companies don't tell the truth to customers. Thanks for your very professional approach! And as last time - my thumbs up!
It's great to get feedback like this - thank you, Martin :-) The videos are really hard work to produce, but as they seem to be helping a lot of people, I'm ok with it. And I'm learning quite a lot myself too!
Found your video whist researching solar optimizers. Did wonder why some installers are claiming they are essential if you have partial shading on your solar string, suggesting shading on one panel will knock all the panels. Clearing not true and thank you for explaining this so well.
Super Information Gary!!!!! Thanks so much. You have made my choice much easier Garry. My 10 panel Qcell Solis sytem in Ireland is costing about 7700. I will also get 32 cent for the energy I export to the grid. My current unit rate I pay for energy is 44 cent. I watched your video on buy now or wait. I think in Ireland buy now is better :)
I found Part 1 last week while searching information on SE optimisers and Enphase micro-inverters, and now you're here with part 2, handily suggested by TH-cam. I found the last and this video very informative so I subscribed. I don't use a lot of electricity and won't for the next at least 5, probably more years: no EV to charge, no heatpump, gas cooking... And I don't have a huge amount of South facing (North-South roof) roof space that is recently renovated, so I plan on getting a small array of 5 or 6 panels... However the day will come that I'll at least have an EV, probably an induction cooktop and/or a heatpump as well. By that time the rest of the South-facing parts of the roof should be renovated and I could expand the solar system. Hard-shading shouldn't be an issue as long as the neighbours don't decide to grow massive trees close to the border. Based on this video I think a system with optimisers isn't for me, but I do consider a simple string versus micro-inverters. The options basically are: 1. Use micro-inverters: per panel monitoring (but is it free to do so?), no loss of production in the other panels if one panel fails or degrades quicker than the rest or has a bunch of leaves on it, no extra cost to split the production over my 3 phase supply. 2. Use a single phase string inverter rated at what I need now, get a second one on a different phase when I expand: no per-panel monitoring, efficiency loss if one panel fails/degrades/dirties, possible phase-balancing issues (only 1, later 2 of the 3 phases get solar injection). 3. Use a 3-phase 2-string inverter that's twice the power of what I currently need: probably the highest up-front cost but expanding is only a matter of buying the solar panels and connecting them up as a second string (spending now to save later?), no phase-balancing issues, but still no per-panel monitoring and efficiency loss per string if one panel fails/degrades/dirties. What would be wisdom?
Real question is whether your setup will be grid-tied or off-grid, and whether you intend to have battery backup. If it's grid-tied and you have no plans for battery backup, microinverters might be the way to go since they can just send AC directly to your panel & the grid without anything extra (they shutoff their output when the grid shuts off). If you DO plan on having battery backup, a hybrid string inverter is probably the way to go. If it's off-grid, you basically NEED a battery... and in order to charge a battery with microinverters, you'd have an extra step to convert back from AC to DC again... then when you pull that power back out of the battery, you lose even more power to another conversion from DC back into AC for your panel/house to use. Hope this helps! Personally, I'm doing a smaller mobile build so I'm just doing a 120V hybrid inverter initially (likely a Growatt 3000 along with a ~5kWh LifePower4 server rack battery). Good thing is, most hybrid inverters like this can be paired up with a second unit later on to produce split-phase 240V AC.
Hiya - glad you're liking my videos! Now, apologies that I don't give people advice (even free advice is fraught with implicit liability) but I highly recommend you join a Facebook group on solar (like the one I mention in my video) - it's a great place to pose problems and ask questions. Good luck! :-)
@@Justin-C I live in Belgium, we either have 2 types of 3-phase networks depending on when the street/area got electricity: either a 3-phase without neutral delta supply with 230V between the phases, or a 3-phase with neutral Y supply with 230V between each phase and neutral and 400V between the phases. We can choose to have either a "single phase" (which sometimes is actually two phases, sometimes 1 phase and a neutral) or 3-phase power in our homes. Since I am renovating and taking into account future induction cooking, heatpump, EV-charger... I chose to get a 3-phase supply which in my case is the 3P+N 400/230V kind with 32A per phase. We have digital smart meters that count consumption and injection seperately, for injection we get about 1/3 of what we pay for consumption, which would be a great argument for having a battery if those things weren't so expensive. We also have a system called "energy sharing" which means we can sell or donate our injected power to friends or family, and only if they don't use it (all) at that moment you sell to the provider at injection price. I would go for that energy sharing system for now: my parents would co-invest in the solar setup and in return I would donate my surplus to them (they don't want the hassle of getting solar panels installed on their own home that has 3 floors between the consumer unit and the roof). Batteries are just too expensive for now and don't provide long-term storage to allow for seasonal equalisation. I would install 5 or 6 panels of around 400Wp. If I go the string route, I could use a Growatt MIC2000TL-X or MIC2500TL-X on a single phase and just get another single phase inverter when I add 5 or 6 more panels. That inverter costs about €400-€500 atm. If I go the micro-inverter route with Enphase, I already have to spend €175,- on a shut-off-relais/phase-coupler, plus €200,- on the "Envoy-S" communication-gateway, plus 5 or 6 €180,- IQ7A micro-inverters for a total of €1275-€1455. That's €875-€945 more than the string inverter. I was of the belief that unoptimised strings are outdated technology, but considering my small array would have the same orientation without hard shadowing I'm not so sure I really need the per-panel optimisation and monitoring I would get with optimisers or micro-inverters considering the extra cost that comes with it...
I only had my solar power system fitted earlier this month and have really enjoyed getting into the technical side of it. Your videos have been the best, most informative I have found, so thank you very much. My system: 18 x 405W Longhi panels Lux Power Tek 6K Hybrid Inverter 2 x Greenlinx 3.2kWh battery Getting a system installed at this time of year, well, of course I am not seeing the best it can do yet, but I have still had some good days, 15.5KWH one day! Not bad for the North of England.
Thanks pretty amazing generation for the time of year, where you are. The New Year is just around the corner and the brighter days are coming. You won't look back! :-) Btw, your array size is similar to what I'm (finally!) hoping to get installed. The date has been pushed back to end Feb... Oh joy....
@@GaryDoesSolar Today was an example of the other end of the spectrum, 1.4kWh. 🤣 A really grey/misty day. I really can't wait to see what I'll generate in the summer months. Ah well, at least February is the month where generation starts to ramp up again. Which kit are you going for? Or is this to be revealed in a later video?
Yeah, I might talk about my setup in a future video. But here’s what I’ve gone for: 19 x Perlight Delta 400W Total Black Mono panels 1 x GivEnergy Hybrid Gen 2 Inverter 2 x GivEnergy 9.5kWh batteries 1 x MyEnergi Eddi Still looking for a good EV charger solution…
@@GaryDoesSolar Sounds great. Nice battery capacity there too. We were not sure if a third battery would help us, the amount we use/the amount we can top up/the amount that the inverter can provide at one time, not sure if we would get the value out of a third battery, time will tell. We might be making an extra purchase! I believe that the Zappi is the go to EV Charger for solar.
I'm in the process of getting PV installed and decided to use microinverters for several reasons. I like the idea that each microinverter has to deal with one panel and don't need an Inverter that has to deal with a whole string. At the same time if a central inverter goes down, then the whole or partial array is offline. With the microinverters only the one or a few are offline and it gives me some extra time for the replacement. Expandability and replacing PV Panels in the future makes it easier since I don't have to worry about compatibility. In my case there is not a big difference in costs between the 2 options. Monitoring is a bonus to a geek 😁 Downside of a microinverter is that the peak power output is lower than the peak output of the PV Panel but after a couple of year the PV Panel will have a reduced power anyway and the 1-2% power consumtion will be from the PV side and not the mains side. According to the manufacturere mentioned in this video, when there is no sun on the PV the microinverter consume several micro Amps. There is also the option to use something like Victron. There each string can have its own MPPT which then can be bundled using a busbar and fed to the inverters and/or batteries. I find there are a lot of options and setups out there. One should take the time and do thier own research before getting one. Its a large investment and once that can be very costly if done wrong. At least videos like yours can minimise such mistakes.👍
Hi Gary, I would just like to say that another very informative video (again). Took the plunge last week and had an x18 half cut panel array, a 6kW hybrid inverter with 7kW hour battery system installed.
@@GaryDoesSolar errm no initially or so the data led me to think initially, now I understand a bit better yes, although I am already thinking of increasing my battery capacity from 7kWh to 10.5 or even 14kWh. See my reply to another post on this video. I didn't realise how much the output drops due to a dull, overcast winters day. I had a very good Friday last week (day 1 after commissioning) where I generated 15kWh and since then if I've had 1kWh per day I have been lucky. Yes, there was a bit of nieveity involved but once I compared instant results with other people then it reassured me that my system was working fine and it was purely a weather situation which was the reason for the extremely poor results. If I hadn't been able to do this compare then my installer would have been getting phone calls as to why.
@@GaryDoesSolar Hi Gary, yes it seems to be going quite well for the time of year. I seem to be outperforming my collegues 8ish array he has about 50 miles away but I think he is at a different angle to me. I would like to suggest to all watchers to join a group or talk to friends / collegues about there daily generation as in winter it is a lot lower than summer and not to get dispondent and question the decision when you (my system) only generates 0.19kWh in a day.
Good update - thanks! I chose to use Tigo optimizers even though I have no shading issues. I installed the system myself and I will be maintaining it, so the monitoring will be extremely useful. Second, we need the safety shutdown at the panel level because of the new electric code in the US. The optimizers have that built in. One last advantage that optimizers have is they get the most out of each panel because each panel has a slightly different output level. I don't know how much it helps, but it probably isn't much.
Thanks Mark, and great to hear that the Tigo optimisers are working out for you. The safety shutdown is certainly a great feature. I general, I'm hoping that the manufacturers of optimiser and microinverter products continually improve reliability rates over time, and this surely will help take up of those products. Looking forward, I see no reason why microinvertors should not become the most popular solution for solar (even over string inverters), given all their benefits. Let's see what happens...
Hi Gary, hello from Perth (Australia, not Scotland ;-) ) Thank you very much for the information you provided in this series, it will be very helpful for me when I change my current system to a bigger one. Particularly interesting for me where half cell panels, and the fact that (some) inverters support two strings, as I have to deal with partial shading, and plan to have panels on two sides of my roof.
Hi Stephan, thanks for taking the time to comment! Now, I've been to Perth (Scotland) many times as this was near where I was born and brought up, but I've never been to Perth (Australia)! I'm hoping one day to get the chance to fly over :-) Good luck with your planned installation!
Great video Gary, interesting facts on the difference between half and full cell panels ... and if I'm honest I agree with your comments referring to optimisers and think why invite reliability problems on a commodity which as you say is difficult to access. If shading isn't an issue I say just go with panels and string inverter alone.
Thanks for your kind words, Rog - it means a lot. I guess I'm not overly excited about optimisers/microinverters in relation to their performance wrt shading. For me, it's all about the value returned against cost, and I don't think there is a large differential between those for shading. But... I actually really like the concept of microinverters, and I believe that they have the potential for being the de facto choice for domestic solar installations globally. So much so, that I'm making a video on that to explain... :-)
Gary’s series on solar is the best on TH-cam in striking a balance between ease of understanding and technical detail. I wish I had this kind of information available when I installed solar on my home four years ago. I’m generally happy with my installation (12 Kilowatts with a SolarEdge inverter) but if I had it to do over again I would have explored going without the inverter and installing more panels (although it’s not clear whether SoCal Edison would have approved a larger system or if I could have found a reliable installer to agree going without inverters). My personal concern is whether or not to expand my system by adding battery capacity. Batteries are still relatively expensive, even with the current 30% tax credit. Additionally, there is the question of how many batteries to install, where to place them, and most importantly what goal I hope to achieve. The important question of return on investment is much more complicated for batteries than it is with solar panels. I would love to have Gary cover this in a future video.
Thanks for the very kind words, Richard. I'm not sure if you saw my video on ROI yet, but it allows you to model different solar/battery solutions to see what their ROI might be: th-cam.com/video/FvjuJQZRrvA/w-d-xo.html
Great video Gary! And not just this one - your videos are all very helpful and educating! Massive amount of good information presented with a good pace and in "easy to handle" portions. Keep up the good work!
Thanks for the two parts Gary, I was very pleased you covered the setup of having panels facing more than one direction. I plan on having panels in three directions to get the best output throughout the day. Think Microinverters will be my choice. Will check out Mark's blog as he is across the ditch as we say in NZ.
Thanks for taking the time to comment, David. And I'm very happy to have provided you with extra information on the topic, to help you make an informed decision. Although my comments to date on microinverters are been in the context of shading, I'm actually quite a fan of where that technology is going - so much so that I'm going to make a dedicated video on microinverters :-) Good luck with your solar journey (would be great to hear how it goes) and it's great to have viewers who are quite literally on the other side of the planet from me! :-)
Excellent video, Gary. One funny thing, recently I saw a picture from the solar community on LinkedIn about "how to do NOT make agrivoltaics". It was nothing more than a very fertile solar roof that allowed the growth of some wild grass between the gaps of the solar panels causing shadow over them.
Thank you! I have been struggling to decide between a string inverter and the micro inverters. My system is to be small and on the ground but I'd like it to be as trouble free and reliable as possible for as long as possible. Great info. Thank you very much for your efficient and understandable presentation.
There is so much value in your video... Very impressing! I wil follow your channel and locking forward to learn from an expert. Best regards from germany
Another brilliant video Gary. Reassuring that the micro-inverters I'm having installed in January because of our panel installation is spread across two roofs on two buildings. Thanks as always for your in-depth research and clear explanations 👏
Here in the Netherlands a big selling point for microinverters is the reduced risk of fire. Especially for installations with more than 10 panels the DC current will over time pose a greater risk. If the connect wears out and corrosion occurs in a connector that can lead to a very hot point of failure and may even cause a fire. The second one you already mentioned, that it is easier to replace a single panel in your system. Although this is very unlikely to be necessary.
Micro-inverters are much safer! Good afternoon and excellent presentation and follow-up. Please let's not forget, if not the most critical aspect of a micro-inverter vs. a string, Safety, and Rapid module/panel level shutdown. I would not want 600 to 1500VDC that can not be shut off over the heads of my loved ones living under my roof with a string inverter. My Family's health and safety are worth a few dollars, which I have recuperated in the long lifespan and increased solar harvest of the NEP microinverter.
Thanks for taking the time to comment. I think many people are slowly starting to see the benefits of microinverters, especially for the mass consumer market, where, statistically, there will be a growing number of incidents. I'd guess that we'd then see safety legislation (like rapid shutdown) that already exists in the US and other countries, being applied throughout the rest of the world.
Gary - great series of videos. I just moved to Octopus Energy and applied your referral code. So £50 should be on its way to you. Thanks for the very informative and useful videos.
Hi Stephen, I received an email yesterday from Octopus about your sign-up - thank you so much for this! Very much appreciated :-) Glad that you're liking my videos. More coming soon...
Great video Gary. I'm planning to move house next year and want to fill the roof of the new house as much as I possibly can with solar panels. You've given me good advise on what to look for when it comes to the installation. 👍
Absolutely brilliant Garry. We need more people like mate. Can you possibly do a video on Selecting the igły inverter / calculations please? Much oblige. Cheers
@@linksone6287 No problem at all 👍 This utility I created allows you try out different inverter sizes to see how they perform against the amount of sun you get, your daily energy usage profile, size and output of any battery and the smart tariff you're on: garydoessolar.com/utilities/dailymodellingutility/ Enjoy! 😃
Thank you Mark - that's very kind of you and much appreciated! And great to hear you're already up and running. My installation tale is a sorry one, having started it nearly a year ago, but I'm looking at the end of February now (fingers crossed). My battery array size will be similar to yours - I think there are revenue opportunities for such capacity :-)
Thanks for your brilliant, clear and concise, no waffle videos. I wonder if someone can help me solve a shading issue I have in the winter months. I have a 5 x 2 row, south-facing REC panel array on a flat roof. The panels are in weighted heavy-duty plastic supports so that the panels are at 15 degree angle. In December, when the sun is low in the sky the 5 front panels shade the bottom 3rd of the rear five panels. This obviously affects power generation at a time of year when it is not very good anyway. In my thinking, the simplest and least technical solution is to raise the height of the rear set of 5 panels so that, rather than being staggered, the two rows are in line with each other and the 2 rows will receive the same sunshine incidence. Does anyone have any suggestions as to how this can be achieved?
The thing I don't like about the micro-inveters (I had enphase on a previous house) is that they are generally grid tied, so unless you have a more complex(and expensive) setup to isolate you from the grid automatically and then kick on another inverter feeding back voltage into the micro-inveters you will have several KW of panels that aren't providing you anything when the grid itself is down.
How does one know what type panel architecture you have? The literature (data sheet) on my Hanwha Q.PEAK DUP BLK-G6 340 says nothing about the diodes or impacts of shading - silent. I have SolarEdge optimizers, and I’m fed up with them. Looking at removing them and the inverter, and just going panel array to inverter. Then the question is, being off grid, what tells the inverter to shut off when the PowerWalls are full? Currently, the Gateway raises the frequency, which the SolarEdge inverter sees as a grid fault, and shuts off. What I’d really like is for the inverter to throttle to meet the load, once the batteries are full, so they don’t shut off entirely. How?
Thanks for the thoughtful info! I would just add that systems with micro-inverters where one fail with reduce your production by that panel only, a system with string inverter that fails stop all production until the inverter can be replaced. Perhaps 2 weeks to 1 month should be expected without production.
Very informative Ive been recommended Perlight Delta 425W Total Black Mono panels. Are these the shingle panels that you refer to? The datasheet refers to a parallel configuration but does not give any details. My roof is subject to dappled shading from neighbours trees, which will only get worse as they continue to grow, so shading is a concern to me, and I have been considering whether or not to use optimisers. Fortunately, it is a flat first floor roof, and access is simple, I just climb out of a bedroom window. Any thoughts?
Hi Jeremy, great that you're getting something out of my video :-) Yes, I have Perlight Delta 415W panels on my roof, which are shingled. I'm sure yours are too. Sorry to hear about the shading you have. As it is from trees (therefore diffuse), optimisers could help here, and having easier access will help in the unlikely event an optimiser fails. Be careful though if you're attempting to resolve issues yourself - your safety is paramount. All the best with whatever you decide.
Thank You Gary, really informative! Exceptional video! Question I have : if panel is fully covered in a shadow ? All bypass diodes will kick in? How single panel like this affects the string of the panels?
You're very welcome - thanks for the great feedback! If a panel is fully covered in shadow, all the bypass diodes in that panel will kick in and so the output for that panel will be zero, but the output of the other panels will be unaffected.
Thanks Gary I can't get any panels for free but I was thinking about getting these for my parents. Half their roof faces north, and it suffers from shading via the chimney I figured it'd still be worth putting them on a north facing roof if the panels are free, and get optimisers instead For myself, I don't really get shading, so I don't bother with optimisers.
What country are you located in, Waqas? If the UK, then North-facing could be a real problem as it will hardly ever get direct sunlight (except in the Summer, depending on the pitch).
Another very useful video. Have subscribed! The MC Electrical reliability report is interesting, especially considering that the Enphase micro inverters have much more to do than the SolarEdge optimizers. From the report they seem to be able to handle the heat and dust in Australia, but what about the cold and wet of northern Europe? Hamburg in my case. Have you come across any reliability figures from installers closer to home?
HI Gary, great videos. I'm interested in upgrading my 12 year old 60 cells panels to increase output and shading performance. I was very interested in the section on shingled panels and your example shows the cell layout for a 10 horizonal row panel. Most shingled panels in the UK from Hyundai and Perlight seem to use 5 or 6 vertical columns and I can't find any info in how these are configured with the by-pass diodes. The graphic at 11:14 shows that shade performance is better for both horizonal and vertical shading but I can't square this. Do you have any insight??
Hi Mark. thanks for the kind words about my videos :-) I wish I'd got into solar 12 years ago - hope you've done well out of the technology so far! Now, for the shingled panel graphic in my video, I can't remember which panel this was from - I think I just scoured the Internet for a reasonably easy to follow layout. What's interesting about many of the layouts is the parallelism, which gives many routes for the current to flow in the event of shading. For information, my own installation comprises 17 x Perlight Delta 415W panels, all mounted horizontally (for no other reason that I could fit more on my roof, which already had 6 velux windows on it. I don't suffer from any shading issues though, so can't comment on their performance with shading management. Having looked on the Perlight website though, there's not too much detail on the internal layout - from what I can see in the diagram on this page, entitled "Full parallel circuit design", it does look like 6 vertical columns in parallel: www.perlight.com/perlight-delta-400w.html
Gary. We are brothers in thought. I have 3 roof aspects to cover in a 5+5+3 configuration. After alot of searching I conclude that a 3 MPPT inverter is the simplest and most reliable way to go. Solis, SMA and Goodwe make 3 MPPT single phase inverters. I just don't know which Mfr is best.
:-) and I agree, a 3 string inverter sounds ideal for you. Worth asking about manufacturers on a local solar forum. Here is a link to a good UK one: facebook.com/groups/2197329430289466
Hi Garry, what type of thermal imaging are you referring to if you say 'specific for solar panels' ? Thank you in advance for your reply and thumbs up for your super videos!
Hi, Gary, thanks for the 2 videos on optimisers advantages/disadvantages. I am considering taking your advice and referral to go with Octopus, but I have a concern over the advantage of Octopus Go and the 4 hour overnight cheap rate. I have a solar system with 8 kWh battery storage and Solis 3.6 kW hybrid inverter. The normal protocol regarding the taking and usage of power for home use is solar, then battery then grid. So if I within the 4 hour rate charge my ev vehicle at my 7kW charger and have set the inverter to charge my batteries at the same time, what will happen? Will the car take the energy at 3.6 kW from the batteries first through the inverter and then take only the remaining kW from the cheap grid rate to make up the 7kW requirement of the charger? OR will it do this AND also charge the batteries as well, thus maintaining the state of charge of the batteries so that I still have sufficient energy to cheaply power the house until the solar kicks in later in the morning? If you have an ev, what do you do to maximise the use of the 4 hour cheap rate?
Hi Barrie, you're most welcome regarding the shading videos - thanks for the feedback! And it would be very kind of you to make use of my referral code and move to Octopus - it all helps with the costs of keeping my channel running :-) Ok, onto overnight charging then. My understanding is this (based on what I've heard as I don't have an EV yet): You can charge your EV and solar battery at the same time - there is a mode on the Solis that allows you to set a timed charge between 00:30 and 04:30 - so no issues there. And of course your grid supply will easily be able to charge both devices concurrently.
I wonder whether your position has altered at all after your recent video with Enphase? I suspect no as I suspect you didn’t learn much more than you already know, but, regardless of that, thank you for these very informative videos. My issue is a complex roof space that would probably end up with too many strings for an average inverter, so an Enphase type system might suit, but the jury is still out and these videos help a lot in the thought process.
No, the Enphase inverter hasn't changed my opinion, which was expressed in my original video: th-cam.com/video/q6t0AAi5Jws/w-d-xo.html Yeah, microinverters could be a good solution for you - or a Tesla Powerwall 3 - see here: th-cam.com/video/sSpQSDSVQ9M/w-d-xo.htmlsi=w6r_lfv-y1-o5NjM
Hello Gary - very interesting video - thanks!. One thing to consider with multiple peaks on the IV curve is that you might expect the newer inverters to perform global sweeps, but the real question is how effective these are. My Solax inverter has this function, but it's disabled by default! You can set it to do the GMPPT every 1/3/4 hours but if the shade is changing, I imagine that this would be far too infrequent. My guess is that the GMPPT function takes some time to perform, thereby limiting the ability to adjust frequently. Am I right in thinking that the MPPT (now thinking of local version, which (according to Solax) sweeps from the right and finds the first peak), is basically adjusting the voltage as the independent variable, and the current is the dependent? in layman's terms, it's essentially swapping part of the current on the string for voltage. By adjusting the voltage upwards, the current is reduced, which means that the resistive effect of shade is less? I ask, because sometimes I see on my string a high voltage when the conditions are poor, and then as the sun comes out, the current increases and voltage decreases. I can understand the current increase as a direct consequence of the sun coming out, but I guess the voltage drop is due to the MPPT (otherwise I believe the voltage would be fairly constant).
Hi Daniel, you're welcome on the video. Yeah, MPPT is a bit of a black art! Global MPPT sweeps do take a little time and you're not generating while they're in progress so limiting the number per hour is a good thing. Trouble is, that you're not then getting the benefit of them! Local MPPT usually can't the other peaks so it's really only Global MPPT that works :-/ Yeah, the only control factor that the inverters has is the voltage.
Hi Gary My pv system has got three arrays, facing directly east, south and west with microinverters. On top of the multiple orientations, there are shading issues, particularly on the south array. These are shingled panels matched with microinverters and the system is producing well, but immediately when shade appears on a panel and starts moving across its surface, the output of the specific panel significantly decreases. Mitigation of the effects of partial shading on pv panels is still a huge challenge. During my research prior to the installation, I found a paper from Germany where they compared 8 pv panels with different technologies for partial shading, in over 1000 scenarios and the shingled panel did better than everyone else. However it was only 15% better than the worse panel and this 15% when translated in kWh was not that much, as ALL the panels under partial shading had reduced output. Nevertheless I went for it, as it is still better than nothing.
Yeah, for your situation, microinverters certainly sounds like a very good solution (as I described in the video). I'm not a big fan of the shading benefits with microinverters, but actually I really like them for a whole variety of reasons - so much so that I'm making a video all about those benefits. Hope you like it - it'll be the video after my next one... :-)
@@GaryDoesSolar My only concern about the microinverters is clipping. Even on a sunny winter day in North London (like today 18 Jan) the south facing panels’ output saturated the microinverters. Certainly energy is lost, but probably not very much. I have researched clipping extensively and I am very much looking forward to your video.
@@serraios1989 I'm coming to the same conclusion. It was a surprise to find out that Enphase's latest microinverter (IQ8) has a power limit that is nowhere near the latest panels with 415kWp. But, the impact of that is lower than you might expect, especially when you take into account panel degradation over a 25-year lifetime.
Very informative vid and as with all things, more info tends to make it a bit more confusing for the newbie. Ive a south facing roof so solar seems ideal. I like the idea of a battery but would also like to use it in case of power cuts but not all systems can do this? Cowboy installers worry me. I recently had 6 gas engineers round to quote for a new boiler and gave them a small list of requirements ie no combi, no budget boilers, got to be reliable and TRVs. Only 2 gave me a quote, the others didnt want to know!
Thanks for the kind words. And yes, it's true the deeper you get into the world of solar, the more involved it seems to get! I'm hoping that my videos go a long way to demystify everything, but maybe I'll have to be doing this for a long time yet - lol You're right - not all battery systems manage power cuts. The only system that manages it well is the Tesla Powerwall, but you'll be on a waiting list for a year to get one, unfortunately. Many other systems provide a couple of dedicated power sockets in the event of power failure, so you'll at least be able to run an extension cable to your WiFi router and TV etc. Yes, like any new market (think double glazing many years ago) there will always be opportunists. I talk a little about this in the podcast I did, referenced in the video, which might be useful to you...
@1701:TheFyldeFlyer I have just had a Sofar HYD6000 hybrid inverter fitted and this has a critical load output or EPS connection which can be wired to supply a smaller consumer unit so that in the event of a power cut the connected batteries can supply the circuits in this consumer unit in the event of a power cut. You also have to have a chnageover switch installed as this prevents the circuits being supplied by 2 different supplies and also stops the inverter supplying all of the other house circuits and the transformer supplying your house as well. The reason for the extra consumer unit is that the inverter can only supply so much electrical load so can't power a whole house system all at once. I think the biggest is generally around 6kW (for single phase). I can't say how good the Sofar setup is as I haven't got the EPS output connected. My installer said that due to not being able to guarantee the earth connection I was told I would need an earth stake and cabling on my property to satisfy wiring regulations. For this and the other associated work required my installer said that the bill for this extra work would be around £1000. When I was looking for quotes for my PV system I started by looking at the MCS website which can show via a Google Map the installers around you geographicially who will have gone through a few more hoops to get the MCS certification. Hope this info is useful to you.
In the US NEC has required rapid shutdown systems which micro-inverters, or DC optimizers provide that functionality. The cost of buying a DC optimizer is only about $$10 more than a rapid shutdown module. That is something to consider most local city inspections will require that rapid shutdown switch. Ground mounted systems don't require the rapid shutdown switch only rooftop.
Super impressed with your solar video series. I'm in the process of deciding on my own solar set up and found your video on microinverters and optimisers very useful. I agree with your conclusion and will not be going that route. Can you recommend an installer who installs the Perlight Delta shingled panels you chose?
Thanks for the kind words, Paul - and I’m very happy to hear that my videos have been so helpful to you. Now, most installers should be able to get hold of those panels are they’re quite popular. Just specify that you’re looking for those particular ones. Good luck!
Thank you for sharing this. I’m considering adding bifacial solar to an arch at the stern of a sailboat as reflections from the sea and the boat might improve the overall wattage. I would appreciate your thoughts on the matter. Thanks.
Hi Muhammed, you're very welcome - great to get feedback like this! And yeah, if you don't have any shading, or only hard shading in places, then optimisers are unlikely to add a lot of value.
Thanks for the kind words, Oleksandr. Now, power generation from solar panels is all about the amount of light hitting them. And unfortunately, cloudy days mean less light. And less light means less power generation. The only solution is to improve the efficiency of solar panels. Today, they’re just over 20% efficient - but the great news is that efficiency is increasing over time as new materials and manufacturing processes and brought to bear 👍🏻
@@GaryDoesSolar You are right, but my question was mostly about string sizing, I do have 7kwt installation (18 panels x 390w 40.8Voc 33.8Vmpp ) and noticed that generation starts from 600v on panels so was thinking that my installation is not optimal but now I have realized that 600V is optimal voltage for my inverter's mppt and when generation starts it starts from that optimal voltage. So adding panels in that string will probably makes no difference is it correct way of thinking? Or if I will add panels to the inverter string and keep it to maximum possible (1000v in my case) it will reach that optimum voltage faster and start generation even with less light from sky?
Hi Gary, a very insightful video and indeed your entire series are a must watch for anyone considering PV install. I am looking in to PV and I do have a three aspect array requirement East / West - Main House roof and South facing detached garage. We do have shading and tree issues (more pronounced in the winter - lower sun angle) so I originally thought I would be installing a Solar Edge optimiser based system, complete with 400w mono black Half- Cell panels, but I must say I am now rethinking it after watching your video, perhaps changing to Shingled design panels? I can't seem to find a three MPPT inverter in the Solar edge range, perhaps It is just not an option? I also looked into the Perlight delta 400w Shingled panels, and they look very good, but perhaps the Hyundai 400w Shingled Panel, which has a 25 year product /25 year performance warranty, seems to trump the Perlight delta 15 year product / 25 year performance warranty? Although the Perlight delta is a more efficient panel (21.3% for the Perlight Delta Vs 20.4% for the Hyundai) perhaps this swayed your choice? Are these the only Shingled PV 400w panels available in the UK currently? I couldn't find anything else.
Thanks for the kind words, Ade. And great to hear that I've got you thinking about your installation options :-) Worth checking on sites like below for any shingled panels: midsummerwholesale.co.uk/buy/perlight-monocrystalline-solar-panels solarsuppliesuk.co.uk/product-category/solar-pv/solar-panels/
Hello Gary! I love your videos! Quick question - for "triangular" shading situation (example terrace wall or half wall on roof), that would cover a triangle from left lower corner of panel towards the middle of the panel on the right side. What would be the best solution? A shingled panel? Some different managment approach? Could you mix different panel variations due to shading issues, but considering all of the panels having the same specs? Sorry for the long question,thank you in advance! :)
Crikey - lots of questions! :-) So for triangular shading, you're likely tripping 2 of the 3 bypass diodes in a typical non-shingled panel. I can't answer easily for a shingled panel, but they're all laid out in different ways, but I suspect it's not going to be too different - you might only get a 3rd of the maximum output. I wouldn't recommend mixing panel specs on the same string as this can give additional issues.
Thanks for the video Gary. I'm not sure I really understood the split panel mptt optimisation, a single panel is easy to follow, but surely with an array of panels if it used half the voltage that would decrease the overall output significantly? It must find an optimum point, but the diodes are either open of closed and I'm thinking that will always be closed so no advantage?
Hi Stephen, you're most welcome. Yeah, the way I like to think about MPPT, is that it appears an intelligent process but it's not. The MPPT controller in a string inverter simply adjusts the voltage from 0 upwards (a sweep) every minute or so, to see which voltage gives the highest current, and therefore the highest power. It doesn't know about bypass diodes or even optimisers, how they work or anything. The problem for the string inverter MPPT controller is that if there is shading only on one panel, it can't really do anything to optimise that because it will surely bring down the current on all the other panels, so in reality, it's only effective if all of the panels in that string have exactly the same kind of shading (say the lower half of each panel shaded by an adjacent building later in the afternoon). In my mind, these conditions are rare, really, what is the increased generation advantage? Interested in your thoughts on this...
@@GaryDoesSolar Definitely sounds rare in a string, but with an optimiser per panel it’s perhaps a further option when all 3 sections have shading on one half. I expect there are other benefits of the split panel, as this one sounds quite marginal. It would seem like smarter electronics in a panel could handle shading better than diodes, but perhaps it’s avoided due to generating heat. I have panels going up tomorrow with a little shading from a chimney, I’ve gone against my installers advice and will try without optimisers and just position the panels away and accept some loss, my feeling is that shadow is only a factor when there is direct sun, and that’s less common anyway later in the year when shadows are longer. It’s an EW roof with a 40 degree tilt so the only months where the sun is high enough to reach the other side limit the shadow length. I wish I could do 3D trig to properly work it out, but alas beyond my maths ability.
@@smc812 Hope all goes well with the installation - and I reckon you'll be fine not having the optimisers given what you say. And there's still plenty of summer left for some nice generation 🙂
Thanks for the Video Gary. When you are saying "Inverter" are you talking about micro inverters only or string inverters as well? I have half cut panels with bypass diodes with an all in one MPPT string inverter.
You're most welcome. Yeah, it can get confusing between "inverter" and "microinverter". So, in my videos, if I just say "inverter" I'm always referring to a string inverter. Hope this helps!
Thanks for the great summary - your channel is really helping me to make some decisions about the system I will install. One question... whilst the panels do a good job of managing shading within an individual panel (especially half-cell panels), won't any shaded panels still limit the power output of all other cells in the string? So if you have a single string of 10 panels with only one that is are partially shaded you are losing quite a lot of power compared to using micro intervers where all non-shaded cells work at full power. Is that correct?
You're very welcome. My analysis tells me it depends on the kind of shading in fact: If it's hard shading (like from another building) then the bypass diodes are pretty good at limiting the effects only to the panels that are shaded - the other non-shaded panels will operate without problem. If it's a large amount of diffuse shading (limiting light to say more than 20% of the panel) then it's as above - the bypass diodes will do their job. But if it's a small amount of diffuse shading (limiting light to say less than 20% of the panel) or if there is shading from a cable or antenna, then the bypass diodes might not be triggered meaning current flow will be limited in the other non-shaded panels as well.
I am using powerwall3 which allows upto 6 strings input. I have two arrays. A 8 panel array in prime sun location. The second array is 16 panels that is effected by tree shading during early morning and mid day. Without using optimizers or microinvertors. Would it be more efficient to have 3 strings on the large array instead of just one large string? As you show that shade or issues with one panel will effect all panels in the same array string.
Very useful! Currently researching what solution to get, and certainly, SolarEdge are very popular - but seeing the reliability review from MC Electrical gives me pause. That said, the review is a few years old now, and Mark admits in more recent comments that he hasn't gone back to the product to see if things have changed. So, it's off to Trustpilot to see if there's some insights to be had there. MC Electrical seem to rate Fronius highly - but there aren't many reviews on TP to make a solid judgement. However, the reviews that do show up there, are largely negative. SolarEdge don't do especially well either on TP, albeit they have more positive reviews than many of their competitors. If that's 'the best' I can get in terms of customer service though, then it's still enticing, even if I don't technically need the 'benefits' of optimisers, and could be risking additional failure points. It's all about whether I'll be looked after if those problems occur. Still, lots more research to do!
Hi Garry great video but feel you have missed some other benefits of microinvertors. You note in video if microinvertor shows issue you can not resolve it. I had a failure and I used the ABB powerone microiinver to reboot and repair microinvertor. You can update microinvertor softwar and change standards as standards evolve. Ours changed and microinver software covered change. If say panel fails I don’t loose string and I actually know which panel failed. We have 20 panels so we loose 1/20 or 5%. Where as string could be effected and you don’t know which is effected panel. Power from microinvertors is cooler as wash is just converting power at lower domestic voltage and ours is 230 volts + or - 10%. So as you noted growing system is easy. But other feature you missed is string connection to main inverter is high voltage hotter connection and a number of fires in Australia were identified as isolation solar switch arching. As each panel has microinverter there is no main inverter to place so installation is quicker and placement of inverter is not an issue. Main inverter run hot and have say 15 year like. As they day you loose all power or one phase. But as microinvertor is running cooler life is longer but as failure occur it will be a unit in many so solar is continued to be generated. I learnt a bit about the improvement in solar cell shading features as our system in circa 2014. So much in 1/2 cell and shingle is new to me as we are not in the market to replace.
Great pair of videos. If you are choosing a panel because of its warranty, how will you know that one of say 20 - 30 panels has fallen to say 85% of rated output when it should be 90%, without optimisers. In the 1st video you said the optimiser could cost as much as a panel. I would like to see a half decent $80 panel, because that is what the Tigos cost here in Australia, or Huawei at about $65-70. THe Huawei optimisers are warranted for 25 years I understand.
Hi double-x :-) thanks for taking the time to comment on my shading videos - very much appreciated! Now, you raise a good point. Without any kind of monitoring, how would you know? And without any panel-based MPPT (either via optimisers or microinverters) how would your system ensure that those panels which have deteriorated the worst, don't bring down production of the others? I mean, it all points to the argument of *having* optimisers/microinverters, but I worry about their reliability, which could end up costing you more than they're saving... That said, I do think there is a case for microinverters as the key to mass adoption of solar - something I'm making a video on shortly... With regard to pricing, your point is valid (wrt optimisers) - they're relatively inexpensive now - although I do believe you have to buy a separate monitoring unit for the array as well?
Hi Garry Just a quick question. Do you have any update on the Tigo optimiser problems outlined by Mark in his blog post?. I have just recieved the design for my system from the installer and they want to use Tigo to handle the East /West split. Im just wondering if we will need the monitering system to make them work. Simon
@@GaryDoesSolar Hi Garry. Thanks for the quick reply. I have decided to get the monitoring system as the price is relitively small compared to the whole system, And if you have these things you might as well know what is going on up there!!
Hi Gary. Excellent video. I don’t get if I had panels on west and east on same string then given panel’s built in bypass diodes then it should handle the shade (or less sunlight) on west panels in the morning while full generation on east and vice versa in the afternoon. I say I don’t get it because you mention in the video that optimzers are needed if panels on same string face different directions
Thanks for the great feedback! Now, the problem comes from the fact that ALL the panels on your West roof will not be generating much in the morning , whereas ALL the panels on your East roof will be generating a lot (assuming a sunny day). The bypass diodes won't be able to handle that mismatch very well. You're far better putting each orientation on its own string as opposed to adding optimisers. Optimisers (and microinverters) work best when there is partial shading within a single orientation.
@@GaryDoesSolar thanks for your reply. I was confused about your video which illustrated it as a bent hose with the current being pulled down by the panels on different orientation - is that indeed true as it would seem to be contrary in my mind with your other examples that indicate if panell(s) are fully shaded and are on the same string, it would not effect power output from other panels; therefore I was assuming in a situation with panels on different orientation but same string could be modelled as simply panels with a lot of shade on them when sun is on the opposite side; does that make sense or am i missing something fundamental in my understanding ?
@@warperone The problem here is that the panels on the East and West roofs are never shaded as such - they're just not seeing direct sun at different times of the day. There is still a lot of ambient light around, and bypass diodes are designed only to manage partial shade.
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Dear TH-cam Algorithm,
I hope you read this.
Recommend "Gary does solar" to everyone. As an electrical engineer, I am inspired by the concise, accurate and technically correct explanations with clear diagrams and explanations.
Thank you!
Thank you - this comment made my day! 😀
You are absolutely correct about Solaredge optimisers. I have 16 panels installed in 2018 and 2 optimisers have already been replaced after they failed. Fortunately mine are easily accessible, so no big deal. Excellent explanations. Thanks.
Yeah, I'm hearing more and more about SolarEdge unit failures - such a shame, really...
"The Tigo Optimizers would not work unless they were connected to the internet"
Thank you for that warning.
When talking to my contractor on what I would like for an installation, I specified "No cloud services whatsoever". They were like "We might have to hack some stuff".
Freaking wild. Cant even buy a brick. It has to be a spy brick.
Yeah, this is the world we seem to be living in now - everything is connected. I can hardly complain about it myself as a lot of my career is in the mobile industry where I developed the technology to do much of that. I get it though, that for many people, they prefer not to have devices around them connected - unless absolutely necessary :-/
As some one new to solar systems and researching to the point of getting a headache, your videos have been very helpful without the need for aspirin.
That's really kind of you to say - I'm humbled, thank you :-)
I suspect that many installers aren't really keeping up with technology developments and simply have a few "recipies" that they choose from that they match against the house configuration and whatever kit they can get at the time.
From what I read, if MCS had any real oversight of those they certify, there would be mandatory ongoing education and training to keep them up to date.
I've yet to pull the trigger on a Solar PV/Battery system for my own house (NE/SW roofs with slight shading from chimney on NE roof), but I won't just be having whatever an installer throws at me. As it's my money and roof, I'll be having the kit *I* decide on.
Another well researched video BTW. Looking forward to your next one ...
You're totally right, Tony - getting true value for money is hard these days, and certainly I've found that having knowledge up front makes a huge difference. Good luck when you pull that trigger... :-)
I have just had (for a week so far) a Tesla PW3 with 11x435W panels across 3 elevations. NE/ES/SW
The installer put them on ONE string, with Tigo optimisers on every panel. I queried this, because the PW3 has 3xMPPT anyway, and surely optimising over a 270' arc is a bit of a stretch???
Having said that, so far I'm achieving the daily expectation for October in my region (7E, north west).
It just makes you wonder if you can achieve more...
I enjoyed both Part-1 and Part-2 Gary ... keep up the good work
Thanks - I'll keep the videos coming :-)
I just wanted to say thanks for your videos. It really helped me talking to the sales person. At least it made me feel I had a level of knowledge that I could ask the right questions. My 14 panels, and 2x 3.2 batteries and 3.6 Lux Hydrid inverter were installed last Wednesday. I can’t stop looking at the monitoring 😊. After you last videos, I checked and we have half cell panels. We have had a few hours of free power. This impressed me for winter. Thanks again. I will still continue to watch.
Thanks for the very kind words, Michael. And also, I really appreciate your “super thanks” - it’s a lot of work to make my videos and so this means a great deal to me 😀👍🏻 Sounds like everything went well with your installation and it’s performing well in the winter, so this sets the scene for even better performance over the next 6 months - all the best!
Absolutely fantastic series Gary. Informative, accurate and concise. I don't think there's a better channel out there explaining the practical considerations and implementation of solar panels out there. Well done!
That's really kind of you to say, Alan - thank you :-)
Best video I’ve seen describing these features.
Thanks Brent - great feedback! :-)
Really a Great Informative videos for PV Fraternity.Thank you so much for your subject narration.I become a core Fan of you Mr Garry
Wow - that's high praise indeed - thank you! I'll keep the videos coming...
Another brilliant video with eye-opening content, which totally reinforces parts of the learning matrix: "There are things, you know you don't know" & "Things you don't know, you don't know"
Always an education and pleasure to watch. Thanks very much for the work and research put into these excellent videos 🙏
Thanks Nic - yeah, it always feels like I'm going down the rabbit hole every time I get into a topic! :-) But great to hear that you and others are getting a lot out of it! :-) I'll try to keep the channel interesting!
Thank you for a great and easy to understand content!
I think you need to add some economical aspects:
- optimizer cost about 55 EUR/per panel (without cost of labor)
- they consume energy as well and it is about 2%, so this can put away the benefits
- to be able to monitor individual panels, as mention their benefit, you need additional management box which cost you additional 250 EUR
I think microinverters are better solution for smaller installations (do optimizer job and convert DC to AC and can be monitored individually without any additional HW) because you are very flexible (different orientation, no need to use "solar cables" for DC, just regular ones for AC) no need of central big inverter which cost from 1000 EUR and more. But at some point, if think only economically, they makes no sense because of the price, e.g. 10x 550 W panel needs 10 microinverters * 220 EUR = 2200 EUR instead of lets say 1500 EUR per central inverter.
Thanks for the extra insight.
Now these videos were focussed on shading, but I plan on making a video on optimisers shortly, just to complete the picture on the dedicated microinverters video I made here: th-cam.com/video/q6t0AAi5Jws/w-d-xo.html
Your conclusions make a lot of sense. I could invest in a high quality, reliable hybrid inverter for considerably less than a micro inverter based system.
Thanks Kevin. Yeah, for management of most types of shading, the bypass diodes in your panels will do a good job in a string inverter system. If you have a lot of trees around, then optimisers and microinverters have some value there.
This is some incredibly useful information, thanks Gary. I have just placed an order for a solar PV system with battery storage and included 8 TIGO optimisers for the south array which will suffer from shading by a large oak tree. In the light of the information you have given, I have contacted my installers to remove the optimisers from my order. Keep up the good work.
Thanks Brian - very happy to have given you sufficient information so you could come to a decision on this. And good luck with the install when it comes!
Hi, Very interested in your decision to not to use TIGOs. I have just has a PV system installed with battery without any TIGOs. Thought installer might have computed estimate wrong as there is a small tree directly South which casts a shadow between 13.00 and 14.30. Trying to decide whether it makes financial sense to add TIgos. Received quotes of £3k for all 15 panels and £1k for 5 panels. So all very interesting. Have you any idea how much extra production you would have got with your 8 TIGOs. Thanks
There's always stuff to learn, who knew shading was so involved. Thanks for this follow up video.
Me neither, John! And you're very welcome! :-)
A quick question, if I may: you did some thermal imaging in one of your recent videos, and as you're pretty expert in photography, what equipment did you use? Was it a standalone unit, or combined with some of your existing camera equipment? And have you ever analysed your arrays with it? Many thanks!
@@GaryDoesSolar I purchased a Hti HT-A1 standalone camera. I'm not sure they are still available new as it's fairly old now.
I had not even thought of using it on my arrays until you covered it in this video, however I will be once we get some better weather.
Looks like a nice little unit! Yeah, will be good to see how your panels are looking under the (IR) spotlight! 🙂
Gary, your video is perfect! Explain everything very comprehensive way and I am really glad and appreciate you said a little bit ugly truth about reliability of system with optimizers...
...and microinverters as well.
Well, everybody should know ALL pros and cons of the systems. Many installation companies don't tell the truth to customers.
Thanks for your very professional approach! And as last time - my thumbs up!
It's great to get feedback like this - thank you, Martin :-) The videos are really hard work to produce, but as they seem to be helping a lot of people, I'm ok with it. And I'm learning quite a lot myself too!
Found your video whist researching solar optimizers. Did wonder why some installers are claiming they are essential if you have partial shading on your solar string, suggesting shading on one panel will knock all the panels. Clearing not true and thank you for explaining this so well.
My pleasure, James :-)
Super Information Gary!!!!! Thanks so much. You have made my choice much easier Garry. My 10 panel Qcell Solis sytem in Ireland is costing about 7700. I will also get 32 cent for the energy I export to the grid. My current unit rate I pay for energy is 44 cent. I watched your video on buy now or wait. I think in Ireland buy now is better :)
Thanks for taking the time to comment, Aisling - I'm very happy to have been able to help you in your solar journey! :-)
I found Part 1 last week while searching information on SE optimisers and Enphase micro-inverters, and now you're here with part 2, handily suggested by TH-cam. I found the last and this video very informative so I subscribed.
I don't use a lot of electricity and won't for the next at least 5, probably more years: no EV to charge, no heatpump, gas cooking... And I don't have a huge amount of South facing (North-South roof) roof space that is recently renovated, so I plan on getting a small array of 5 or 6 panels...
However the day will come that I'll at least have an EV, probably an induction cooktop and/or a heatpump as well. By that time the rest of the South-facing parts of the roof should be renovated and I could expand the solar system.
Hard-shading shouldn't be an issue as long as the neighbours don't decide to grow massive trees close to the border.
Based on this video I think a system with optimisers isn't for me, but I do consider a simple string versus micro-inverters.
The options basically are:
1. Use micro-inverters: per panel monitoring (but is it free to do so?), no loss of production in the other panels if one panel fails or degrades quicker than the rest or has a bunch of leaves on it, no extra cost to split the production over my 3 phase supply.
2. Use a single phase string inverter rated at what I need now, get a second one on a different phase when I expand: no per-panel monitoring, efficiency loss if one panel fails/degrades/dirties, possible phase-balancing issues (only 1, later 2 of the 3 phases get solar injection).
3. Use a 3-phase 2-string inverter that's twice the power of what I currently need: probably the highest up-front cost but expanding is only a matter of buying the solar panels and connecting them up as a second string (spending now to save later?), no phase-balancing issues, but still no per-panel monitoring and efficiency loss per string if one panel fails/degrades/dirties.
What would be wisdom?
Real question is whether your setup will be grid-tied or off-grid, and whether you intend to have battery backup.
If it's grid-tied and you have no plans for battery backup, microinverters might be the way to go since they can just send AC directly to your panel & the grid without anything extra (they shutoff their output when the grid shuts off). If you DO plan on having battery backup, a hybrid string inverter is probably the way to go.
If it's off-grid, you basically NEED a battery... and in order to charge a battery with microinverters, you'd have an extra step to convert back from AC to DC again... then when you pull that power back out of the battery, you lose even more power to another conversion from DC back into AC for your panel/house to use.
Hope this helps! Personally, I'm doing a smaller mobile build so I'm just doing a 120V hybrid inverter initially (likely a Growatt 3000 along with a ~5kWh LifePower4 server rack battery). Good thing is, most hybrid inverters like this can be paired up with a second unit later on to produce split-phase 240V AC.
Hiya - glad you're liking my videos! Now, apologies that I don't give people advice (even free advice is fraught with implicit liability) but I highly recommend you join a Facebook group on solar (like the one I mention in my video) - it's a great place to pose problems and ask questions. Good luck! :-)
@@Justin-C I live in Belgium, we either have 2 types of 3-phase networks depending on when the street/area got electricity: either a 3-phase without neutral delta supply with 230V between the phases, or a 3-phase with neutral Y supply with 230V between each phase and neutral and 400V between the phases. We can choose to have either a "single phase" (which sometimes is actually two phases, sometimes 1 phase and a neutral) or 3-phase power in our homes. Since I am renovating and taking into account future induction cooking, heatpump, EV-charger... I chose to get a 3-phase supply which in my case is the 3P+N 400/230V kind with 32A per phase.
We have digital smart meters that count consumption and injection seperately, for injection we get about 1/3 of what we pay for consumption, which would be a great argument for having a battery if those things weren't so expensive. We also have a system called "energy sharing" which means we can sell or donate our injected power to friends or family, and only if they don't use it (all) at that moment you sell to the provider at injection price.
I would go for that energy sharing system for now: my parents would co-invest in the solar setup and in return I would donate my surplus to them (they don't want the hassle of getting solar panels installed on their own home that has 3 floors between the consumer unit and the roof). Batteries are just too expensive for now and don't provide long-term storage to allow for seasonal equalisation.
I would install 5 or 6 panels of around 400Wp. If I go the string route, I could use a Growatt MIC2000TL-X or MIC2500TL-X on a single phase and just get another single phase inverter when I add 5 or 6 more panels. That inverter costs about €400-€500 atm.
If I go the micro-inverter route with Enphase, I already have to spend €175,- on a shut-off-relais/phase-coupler, plus €200,- on the "Envoy-S" communication-gateway, plus 5 or 6 €180,- IQ7A micro-inverters for a total of €1275-€1455. That's €875-€945 more than the string inverter.
I was of the belief that unoptimised strings are outdated technology, but considering my small array would have the same orientation without hard shadowing I'm not so sure I really need the per-panel optimisation and monitoring I would get with optimisers or micro-inverters considering the extra cost that comes with it...
Genuinely helpful Gary, thank you.
You're very welcome, Jim - thanks for letting me know :-)
Thank you! The information you provided here is very valuable. I will recommend it to my solar friends in Latvia.
You're very welcome, Andris!
And thank you so much for recommending my video to your friends :-)
I just learnt something about panels half cell is better than full cell panel. Thank you
Great, and you’re most welcome 👍🏻
I only had my solar power system fitted earlier this month and have really enjoyed getting into the technical side of it. Your videos have been the best, most informative I have found, so thank you very much.
My system:
18 x 405W Longhi panels
Lux Power Tek 6K Hybrid Inverter
2 x Greenlinx 3.2kWh battery
Getting a system installed at this time of year, well, of course I am not seeing the best it can do yet, but I have still had some good days, 15.5KWH one day! Not bad for the North of England.
Thanks pretty amazing generation for the time of year, where you are. The New Year is just around the corner and the brighter days are coming. You won't look back! :-)
Btw, your array size is similar to what I'm (finally!) hoping to get installed. The date has been pushed back to end Feb... Oh joy....
@@GaryDoesSolar Today was an example of the other end of the spectrum, 1.4kWh. 🤣 A really grey/misty day. I really can't wait to see what I'll generate in the summer months.
Ah well, at least February is the month where generation starts to ramp up again.
Which kit are you going for? Or is this to be revealed in a later video?
Yeah, I might talk about my setup in a future video. But here’s what I’ve gone for:
19 x Perlight Delta 400W Total Black Mono panels
1 x GivEnergy Hybrid Gen 2 Inverter
2 x GivEnergy 9.5kWh batteries
1 x MyEnergi Eddi
Still looking for a good EV charger solution…
@@GaryDoesSolar Sounds great. Nice battery capacity there too.
We were not sure if a third battery would help us, the amount we use/the amount we can top up/the amount that the inverter can provide at one time, not sure if we would get the value out of a third battery, time will tell. We might be making an extra purchase!
I believe that the Zappi is the go to EV Charger for solar.
Yeah, agreed - Zappi seems to be the way to go...
Good information! Seems like no matter how much solar research you do or how many videos you watch on it, there's always more to learn.
Thanks, Justin - yeah, the more I dig, the more I find! Lol
I'm in the process of getting PV installed and decided to use microinverters for several reasons. I like the idea that each microinverter has to deal with one panel and don't need an Inverter that has to deal with a whole string. At the same time if a central inverter goes down, then the whole or partial array is offline. With the microinverters only the one or a few are offline and it gives me some extra time for the replacement.
Expandability and replacing PV Panels in the future makes it easier since I don't have to worry about compatibility.
In my case there is not a big difference in costs between the 2 options.
Monitoring is a bonus to a geek 😁
Downside of a microinverter is that the peak power output is lower than the peak output of the PV Panel but after a couple of year the PV Panel will have a reduced power anyway and the 1-2% power consumtion will be from the PV side and not the mains side.
According to the manufacturere mentioned in this video, when there is no sun on the PV the microinverter consume several micro Amps.
There is also the option to use something like Victron. There each string can have its own MPPT which then can be bundled using a busbar and fed to the inverters and/or batteries.
I find there are a lot of options and setups out there. One should take the time and do thier own research before getting one. Its a large investment and once that can be very costly if done wrong. At least videos like yours can minimise such mistakes.👍
Great summary!
Super presentation love the voice tone + explanations !!! BRAVO
Hi Alex - that's so great to hear! Thanks for taking the time to comment. I'll keep the videos coming (next one is uploading right now...) :-)
Hi Gary, I would just like to say that another very informative video (again). Took the plunge last week and had an x18 half cut panel array, a 6kW hybrid inverter with 7kW hour battery system installed.
Thanks Adrian - and great to hear you've taken the plunge! Sounds like a very nice setup! Is it all working as expected?
@@GaryDoesSolar errm no initially or so the data led me to think initially, now I understand a bit better yes, although I am already thinking of increasing my battery capacity from 7kWh to 10.5 or even 14kWh. See my reply to another post on this video. I didn't realise how much the output drops due to a dull, overcast winters day. I had a very good Friday last week (day 1 after commissioning) where I generated 15kWh and since then if I've had 1kWh per day I have been lucky. Yes, there was a bit of nieveity involved but once I compared instant results with other people then it reassured me that my system was working fine and it was purely a weather situation which was the reason for the extremely poor results. If I hadn't been able to do this compare then my installer would have been getting phone calls as to why.
Ok, so it's actually sounding quite good so far... sunnier days are around the corner (I hope!)
@@GaryDoesSolar Hi Gary, yes it seems to be going quite well for the time of year. I seem to be outperforming my collegues 8ish array he has about 50 miles away but I think he is at a different angle to me. I would like to suggest to all watchers to join a group or talk to friends / collegues about there daily generation as in winter it is a lot lower than summer and not to get dispondent and question the decision when you (my system) only generates 0.19kWh in a day.
Good update - thanks! I chose to use Tigo optimizers even though I have no shading issues. I installed the system myself and I will be maintaining it, so the monitoring will be extremely useful. Second, we need the safety shutdown at the panel level because of the new electric code in the US. The optimizers have that built in. One last advantage that optimizers have is they get the most out of each panel because each panel has a slightly different output level. I don't know how much it helps, but it probably isn't much.
Thanks Mark, and great to hear that the Tigo optimisers are working out for you. The safety shutdown is certainly a great feature.
I general, I'm hoping that the manufacturers of optimiser and microinverter products continually improve reliability rates over time, and this surely will help take up of those products. Looking forward, I see no reason why microinvertors should not become the most popular solution for solar (even over string inverters), given all their benefits. Let's see what happens...
Hi Gary, hello from Perth (Australia, not Scotland ;-) )
Thank you very much for the information you provided in this series, it will be very helpful for me when I change my current system to a bigger one.
Particularly interesting for me where half cell panels, and the fact that (some) inverters support two strings, as I have to deal with partial shading, and plan to have panels on two sides of my roof.
Hi Stephan, thanks for taking the time to comment! Now, I've been to Perth (Scotland) many times as this was near where I was born and brought up, but I've never been to Perth (Australia)! I'm hoping one day to get the chance to fly over :-) Good luck with your planned installation!
Great video Gary, interesting facts on the difference between half and full cell panels ... and if I'm honest I agree with your comments referring to optimisers and think why invite reliability problems on a commodity which as you say is difficult to access. If shading isn't an issue I say just go with panels and string inverter alone.
Thanks for your kind words, Rog - it means a lot.
I guess I'm not overly excited about optimisers/microinverters in relation to their performance wrt shading. For me, it's all about the value returned against cost, and I don't think there is a large differential between those for shading.
But... I actually really like the concept of microinverters, and I believe that they have the potential for being the de facto choice for domestic solar installations globally. So much so, that I'm making a video on that to explain... :-)
Gary’s series on solar is the best on TH-cam in striking a balance between ease of understanding and technical detail. I wish I had this kind of information available when I installed solar on my home four years ago. I’m generally happy with my installation (12 Kilowatts with a SolarEdge inverter) but if I had it to do over again I would have explored going without the inverter and installing more panels (although it’s not clear whether SoCal Edison would have approved a larger system or if I could have found a reliable installer to agree going without inverters). My personal concern is whether or not to expand my system by adding battery capacity. Batteries are still relatively expensive, even with the current 30% tax credit. Additionally, there is the question of how many batteries to install, where to place them, and most importantly what goal I hope to achieve. The important question of return on investment is much more complicated for batteries than it is with solar panels. I would love to have Gary cover this in a future video.
Thanks for the very kind words, Richard. I'm not sure if you saw my video on ROI yet, but it allows you to model different solar/battery solutions to see what their ROI might be: th-cam.com/video/FvjuJQZRrvA/w-d-xo.html
@@GaryDoesSolar Thanks for the link, Gary!
Great video Gary! And not just this one - your videos are all very helpful and educating! Massive amount of good information presented with a good pace and in "easy to handle" portions. Keep up the good work!
Thanks Apu - it's great to get feedback like this. It tells me I must be doing something of value to others :-) Next video out shortly!
Thanks for the two parts Gary, I was very pleased you covered the setup of having panels facing more than one direction. I plan on having panels in three directions to get the best output throughout the day. Think Microinverters will be my choice.
Will check out Mark's blog as he is across the ditch as we say in NZ.
Thanks for taking the time to comment, David. And I'm very happy to have provided you with extra information on the topic, to help you make an informed decision. Although my comments to date on microinverters are been in the context of shading, I'm actually quite a fan of where that technology is going - so much so that I'm going to make a dedicated video on microinverters :-) Good luck with your solar journey (would be great to hear how it goes) and it's great to have viewers who are quite literally on the other side of the planet from me! :-)
Excellent video, Gary. One funny thing, recently I saw a picture from the solar community on LinkedIn about "how to do NOT make agrivoltaics". It was nothing more than a very fertile solar roof that allowed the growth of some wild grass between the gaps of the solar panels causing shadow over them.
You have to laugh, eh? :-)
Glad you enjoyed my latest video, btw!
Thank you! I have been struggling to decide between a string inverter and the micro inverters. My system is to be small and on the ground but I'd like it to be as trouble free and reliable as possible for as long as possible. Great info. Thank you very much for your efficient and understandable presentation.
Cheers Gary - thanks for the kind words and all the best with whatever you decide :-)
There is so much value in your video... Very impressing!
I wil follow your channel and locking forward to learn from an expert. Best regards from germany
Hi Andreas, you're most welcome! And thanks for subscribing - I'll keep the videos coming! :-)
Another brilliant video Gary. Reassuring that the micro-inverters I'm having installed in January because of our panel installation is spread across two roofs on two buildings. Thanks as always for your in-depth research and clear explanations 👏
My pleasure Paul. It's quite a lot of work, researching everything, but comments like this make it all worthwhile! :-)
Here in the Netherlands a big selling point for microinverters is the reduced risk of fire. Especially for installations with more than 10 panels the DC current will over time pose a greater risk. If the connect wears out and corrosion occurs in a connector that can lead to a very hot point of failure and may even cause a fire.
The second one you already mentioned, that it is easier to replace a single panel in your system. Although this is very unlikely to be necessary.
Thanks Jeroll - these are great points. I think safety of solar installations is going to become more and more prominent as the mass market grows.
I've also heard people are not getting home insurance renewed because of high DC voltage from Solar Panels?
Outstanding work, as always, Gary. Keep it up!
Thanks Tim - this particular video was really hard work - took me much longer than before for some reason. I need to become more efficient!!
Micro-inverters are much safer!
Good afternoon and excellent presentation and follow-up.
Please let's not forget, if not the most critical aspect of a micro-inverter vs. a string, Safety, and Rapid module/panel level shutdown. I would not want 600 to 1500VDC that can not be shut off over the heads of my loved ones living under my roof with a string inverter. My Family's health and safety are worth a few dollars, which I have recuperated in the long lifespan and increased solar harvest of the NEP microinverter.
Thanks for taking the time to comment. I think many people are slowly starting to see the benefits of microinverters, especially for the mass consumer market, where, statistically, there will be a growing number of incidents. I'd guess that we'd then see safety legislation (like rapid shutdown) that already exists in the US and other countries, being applied throughout the rest of the world.
Gary - great series of videos. I just moved to Octopus Energy and applied your referral code. So £50 should be on its way to you. Thanks for the very informative and useful videos.
Hi Stephen, I received an email yesterday from Octopus about your sign-up - thank you so much for this! Very much appreciated :-) Glad that you're liking my videos. More coming soon...
@@GaryDoesSolar and I got £50 credit it out it too - bargain! 🙂
Gary, A very informative series of video. Many thanks for sharing
My pleasure, Dan - thanks for taking the time to watch them! :-)
Probably the best video on the topic.
Thank you 🙏
Great video Gary. I'm planning to move house next year and want to fill the roof of the new house as much as I possibly can with solar panels. You've given me good advise on what to look for when it comes to the installation. 👍
Thanks Craig - great to hear and all the best with your solar plans!
Absolutely brilliant Garry. We need more people like mate. Can you possibly do a video on Selecting the igły inverter / calculations please? Much oblige. Cheers
Thanks very much for these kind words 🙏 which inverter?
My apology! It’s a typing error! It’s just general process of how to calculate and select the correct Inverter in various installations.
@@linksone6287 No problem at all 👍 This utility I created allows you try out different inverter sizes to see how they perform against the amount of sun you get, your daily energy usage profile, size and output of any battery and the smart tariff you're on: garydoessolar.com/utilities/dailymodellingutility/
Enjoy! 😃
Another great video Gary. Keep it coming. Learning more and more about solar.
Thank you! Already working on the next one... :-)
@@GaryDoesSolar What do you use for the animation?
Try not to laugh, but it's all Microsoft PowerPoint! 🙂
@@GaryDoesSolar wow, that's some impressive powerpoint skills. I might give it a go now that I can see what its capable of.
Thanks - yeah, it's actually quite powerful. The only problem is, I can't get it to generate 4K output
thanks again GARRY octipus referal done My system is now up and running! Just waiting on 3rd 5.7kw battery
Thank you Mark - that's very kind of you and much appreciated! And great to hear you're already up and running. My installation tale is a sorry one, having started it nearly a year ago, but I'm looking at the end of February now (fingers crossed). My battery array size will be similar to yours - I think there are revenue opportunities for such capacity :-)
Thank you so much for your informative videos, they helped me so much.
You're most welcome, Mike - thanks for the great feedback! I'll keep the videos coming :-)
God bless you, Gary.
Hope the video was useful 🙏
Good clear presentation. Thanks very much
You're very welcome - thank you for the great feedback!
Fantastic videos, great detail and well presented
Thank you, Peter - great to have feedback like this 😀👍🏻
Thanks for your brilliant, clear and concise, no waffle videos.
I wonder if someone can help me solve a shading issue I have in the winter months.
I have a 5 x 2 row, south-facing REC panel array on a flat roof. The panels are in weighted heavy-duty plastic supports so that the panels are at 15 degree angle. In December, when the sun is low in the sky the 5 front panels shade the bottom 3rd of the rear five panels. This obviously affects power generation at a time of year when it is not very good anyway. In my thinking, the simplest and least technical solution is to raise the height of the rear set of 5 panels so that, rather than being staggered, the two rows are in line with each other and the 2 rows will receive the same sunshine incidence.
Does anyone have any suggestions as to how this can be achieved?
Thanks for the very kind words, Alan - very much appreciated!
Hopefully someone will have answers to your question...
The thing I don't like about the micro-inveters (I had enphase on a previous house) is that they are generally grid tied, so unless you have a more complex(and expensive) setup to isolate you from the grid automatically and then kick on another inverter feeding back voltage into the micro-inveters you will have several KW of panels that aren't providing you anything when the grid itself is down.
Hi Michael, this is a good point, and once I hadn't considered to date - thank you!
Great informative video. Thanks
Thanks Sam! :-)
This video is great again Gary.
Thanks Phil 😀👍🏻
And if you have the room, you could take the money saved on the power optimizers and spend it on additional panels. Giving you more power.
I can't argue with that :-)
How does one know what type panel architecture you have? The literature (data sheet) on my Hanwha Q.PEAK DUP BLK-G6 340 says nothing about the diodes or impacts of shading - silent. I have SolarEdge optimizers, and I’m fed up with them. Looking at removing them and the inverter, and just going panel array to inverter. Then the question is, being off grid, what tells the inverter to shut off when the PowerWalls are full? Currently, the Gateway raises the frequency, which the SolarEdge inverter sees as a grid fault, and shuts off. What I’d really like is for the inverter to throttle to meet the load, once the batteries are full, so they don’t shut off entirely. How?
Thankyou. A very well put together video.
Thanks Andy - much appreciated!
Another very informative video cheers Gary
Thanks Mark. This particular video was the most difficult one to make so far - took ages! Great that you liked it!
Great information Gary; thanks.
My pleasure - thanks for watching! :-)
very informative and useful! Thanks!
You're most welcome, Tomek - thanks for the great feedback! :-)
Thanks for the thoughtful info! I would just add that systems with micro-inverters where one fail with reduce your production by that panel only, a system with string inverter that fails stop all production until the inverter can be replaced. Perhaps 2 weeks to 1 month should be expected without production.
Agreed
Very informative Ive been recommended Perlight Delta 425W Total Black Mono panels. Are these the shingle panels that you refer to? The datasheet refers to a parallel configuration but does not give any details. My roof is subject to dappled shading from neighbours trees, which will only get worse as they continue to grow, so shading is a concern to me, and I have been considering whether or not to use optimisers. Fortunately, it is a flat first floor roof, and access is simple, I just climb out of a bedroom window. Any thoughts?
Hi Jeremy, great that you're getting something out of my video :-)
Yes, I have Perlight Delta 415W panels on my roof, which are shingled. I'm sure yours are too. Sorry to hear about the shading you have. As it is from trees (therefore diffuse), optimisers could help here, and having easier access will help in the unlikely event an optimiser fails. Be careful though if you're attempting to resolve issues yourself - your safety is paramount. All the best with whatever you decide.
Very comprehensive 👍
Thanks Stuart :-)
Impressive video and grafics,⭐️⭐️⭐️⭐️⭐️
Thanks Jonas :-) :-) :-) I'll keep the videos coming!
I just installed 10 x 410w panels with Tigos, My wall panels perform now better. Old ones were 8x 370 w panels.
Great to hear! :-)
Great stuff Gary!!
Thanks Peter :-)
Thank You Gary, really informative! Exceptional video!
Question I have : if panel is fully covered in a shadow ? All bypass diodes will kick in? How single panel like this affects the string of the panels?
You're very welcome - thanks for the great feedback! If a panel is fully covered in shadow, all the bypass diodes in that panel will kick in and so the output for that panel will be zero, but the output of the other panels will be unaffected.
Good advice on two strings arrays!
Great to hear my videos are helping you out! :-)
Thanks Gary
I can't get any panels for free but I was thinking about getting these for my parents. Half their roof faces north, and it suffers from shading via the chimney
I figured it'd still be worth putting them on a north facing roof if the panels are free, and get optimisers instead
For myself, I don't really get shading, so I don't bother with optimisers.
What country are you located in, Waqas? If the UK, then North-facing could be a real problem as it will hardly ever get direct sunlight (except in the Summer, depending on the pitch).
Another very useful video. Have subscribed!
The MC Electrical reliability report is interesting, especially considering that the Enphase micro inverters have much more to do than the SolarEdge optimizers. From the report they seem to be able to handle the heat and dust in Australia, but what about the cold and wet of northern Europe? Hamburg in my case. Have you come across any reliability figures from installers closer to home?
Thanks Tim. Getting hold of reliability data is not easy, but I'm hoping to be interviewing Enphase soon...
HI Gary, great videos. I'm interested in upgrading my 12 year old 60 cells panels to increase output and shading performance. I was very interested in the section on shingled panels and your example shows the cell layout for a 10 horizonal row panel. Most shingled panels in the UK from Hyundai and Perlight seem to use 5 or 6 vertical columns and I can't find any info in how these are configured with the by-pass diodes. The graphic at 11:14 shows that shade performance is better for both horizonal and vertical shading but I can't square this. Do you have any insight??
Hi Mark. thanks for the kind words about my videos :-) I wish I'd got into solar 12 years ago - hope you've done well out of the technology so far!
Now, for the shingled panel graphic in my video, I can't remember which panel this was from - I think I just scoured the Internet for a reasonably easy to follow layout. What's interesting about many of the layouts is the parallelism, which gives many routes for the current to flow in the event of shading.
For information, my own installation comprises 17 x Perlight Delta 415W panels, all mounted horizontally (for no other reason that I could fit more on my roof, which already had 6 velux windows on it. I don't suffer from any shading issues though, so can't comment on their performance with shading management.
Having looked on the Perlight website though, there's not too much detail on the internal layout - from what I can see in the diagram on this page, entitled "Full parallel circuit design", it does look like 6 vertical columns in parallel: www.perlight.com/perlight-delta-400w.html
Gary. We are brothers in thought. I have 3 roof aspects to cover in a 5+5+3 configuration. After alot of searching I conclude that a 3 MPPT inverter is the simplest and most reliable way to go. Solis, SMA and Goodwe make 3 MPPT single phase inverters.
I just don't know which Mfr is best.
:-) and I agree, a 3 string inverter sounds ideal for you.
Worth asking about manufacturers on a local solar forum. Here is a link to a good UK one: facebook.com/groups/2197329430289466
Well done Gary
Thanks Andy :-) That video was a tough one to make! Took ages for some reason in the edit.
Hi Garry, what type of thermal imaging are you referring to if you say 'specific for solar panels' ? Thank you in advance for your reply and thumbs up for your super videos!
Cheers for the great feedback, Renout. The thermal imaging camera I have is this one: www.flir.co.uk/products/flir-one-pro/
Thanks, for the great job.
Cheers Norman - this is great feedback to receive! :-)
Hi, Gary, thanks for the 2 videos on optimisers advantages/disadvantages.
I am considering taking your advice and referral to go with Octopus, but I have a concern over the advantage of Octopus Go and the 4 hour overnight cheap rate. I have a solar system with 8 kWh battery storage and Solis 3.6 kW hybrid inverter. The normal protocol regarding the taking and usage of power for home use is solar, then battery then grid. So if I within the 4 hour rate charge my ev vehicle at my 7kW charger and have set the inverter to charge my batteries at the same time, what will happen? Will the car take the energy at 3.6 kW from the batteries first through the inverter and then take only the remaining kW from the cheap grid rate to make up the 7kW requirement of the charger? OR will it do this AND also charge the batteries as well, thus maintaining the state of charge of the batteries so that I still have sufficient energy to cheaply power the house until the solar kicks in later in the morning? If you have an ev, what do you do to maximise the use of the 4 hour cheap rate?
Hi Barrie, you're most welcome regarding the shading videos - thanks for the feedback! And it would be very kind of you to make use of my referral code and move to Octopus - it all helps with the costs of keeping my channel running :-)
Ok, onto overnight charging then. My understanding is this (based on what I've heard as I don't have an EV yet):
You can charge your EV and solar battery at the same time - there is a mode on the Solis that allows you to set a timed charge between 00:30 and 04:30 - so no issues there. And of course your grid supply will easily be able to charge both devices concurrently.
I wonder whether your position has altered at all after your recent video with Enphase? I suspect no as I suspect you didn’t learn much more than you already know, but, regardless of that, thank you for these very informative videos. My issue is a complex roof space that would probably end up with too many strings for an average inverter, so an Enphase type system might suit, but the jury is still out and these videos help a lot in the thought process.
No, the Enphase inverter hasn't changed my opinion, which was expressed in my original video: th-cam.com/video/q6t0AAi5Jws/w-d-xo.html
Yeah, microinverters could be a good solution for you - or a Tesla Powerwall 3 - see here: th-cam.com/video/sSpQSDSVQ9M/w-d-xo.htmlsi=w6r_lfv-y1-o5NjM
Great work!
Thank you! 🙏 😀
Hello Gary - very interesting video - thanks!. One thing to consider with multiple peaks on the IV curve is that you might expect the newer inverters to perform global sweeps, but the real question is how effective these are. My Solax inverter has this function, but it's disabled by default! You can set it to do the GMPPT every 1/3/4 hours but if the shade is changing, I imagine that this would be far too infrequent. My guess is that the GMPPT function takes some time to perform, thereby limiting the ability to adjust frequently.
Am I right in thinking that the MPPT (now thinking of local version, which (according to Solax) sweeps from the right and finds the first peak), is basically adjusting the voltage as the independent variable, and the current is the dependent? in layman's terms, it's essentially swapping part of the current on the string for voltage. By adjusting the voltage upwards, the current is reduced, which means that the resistive effect of shade is less?
I ask, because sometimes I see on my string a high voltage when the conditions are poor, and then as the sun comes out, the current increases and voltage decreases. I can understand the current increase as a direct consequence of the sun coming out, but I guess the voltage drop is due to the MPPT (otherwise I believe the voltage would be fairly constant).
Hi Daniel, you're welcome on the video. Yeah, MPPT is a bit of a black art!
Global MPPT sweeps do take a little time and you're not generating while they're in progress so limiting the number per hour is a good thing. Trouble is, that you're not then getting the benefit of them!
Local MPPT usually can't the other peaks so it's really only Global MPPT that works :-/
Yeah, the only control factor that the inverters has is the voltage.
Hi Gary
My pv system has got three arrays, facing directly east, south and west with microinverters. On top of the multiple orientations, there are shading issues, particularly on the south array. These are shingled panels matched with microinverters and the system is producing well, but immediately when shade appears on a panel and starts moving across its surface, the output of the specific panel significantly decreases.
Mitigation of the effects of partial shading on pv panels is still a huge challenge.
During my research prior to the installation, I found a paper from Germany where they compared 8 pv panels with different technologies for partial shading, in over 1000 scenarios and the shingled panel did better than everyone else. However it was only 15% better than the worse panel and this 15% when translated in kWh was not that much, as ALL the panels under partial shading had reduced output. Nevertheless I went for it, as it is still better than nothing.
Yeah, for your situation, microinverters certainly sounds like a very good solution (as I described in the video). I'm not a big fan of the shading benefits with microinverters, but actually I really like them for a whole variety of reasons - so much so that I'm making a video all about those benefits. Hope you like it - it'll be the video after my next one... :-)
@@GaryDoesSolar
My only concern about the microinverters is clipping. Even on a sunny winter day in North London (like today 18 Jan) the south facing panels’ output saturated the microinverters. Certainly energy is lost, but probably not very much. I have researched clipping extensively and I am very much looking forward to your video.
@@serraios1989 I'm coming to the same conclusion. It was a surprise to find out that Enphase's latest microinverter (IQ8) has a power limit that is nowhere near the latest panels with 415kWp. But, the impact of that is lower than you might expect, especially when you take into account panel degradation over a 25-year lifetime.
Thank you…very helpful..
My pleasure 😀 cheers!
Very informative vid and as with all things, more info tends to make it a bit more confusing for the newbie. Ive a south facing roof so solar seems ideal. I like the idea of a battery but would also like to use it in case of power cuts but not all systems can do this?
Cowboy installers worry me. I recently had 6 gas engineers round to quote for a new boiler and gave them a small list of requirements ie no combi, no budget boilers, got to be reliable and TRVs. Only 2 gave me a quote, the others didnt want to know!
Thanks for the kind words. And yes, it's true the deeper you get into the world of solar, the more involved it seems to get! I'm hoping that my videos go a long way to demystify everything, but maybe I'll have to be doing this for a long time yet - lol
You're right - not all battery systems manage power cuts. The only system that manages it well is the Tesla Powerwall, but you'll be on a waiting list for a year to get one, unfortunately. Many other systems provide a couple of dedicated power sockets in the event of power failure, so you'll at least be able to run an extension cable to your WiFi router and TV etc.
Yes, like any new market (think double glazing many years ago) there will always be opportunists. I talk a little about this in the podcast I did, referenced in the video, which might be useful to you...
@1701:TheFyldeFlyer
I have just had a Sofar HYD6000 hybrid inverter fitted and this has a critical load output or EPS connection which can be wired to supply a smaller consumer unit so that in the event of a power cut the connected batteries can supply the circuits in this consumer unit in the event of a power cut. You also have to have a chnageover switch installed as this prevents the circuits being supplied by 2 different supplies and also stops the inverter supplying all of the other house circuits and the transformer supplying your house as well. The reason for the extra consumer unit is that the inverter can only supply so much electrical load so can't power a whole house system all at once. I think the biggest is generally around 6kW (for single phase). I can't say how good the Sofar setup is as I haven't got the EPS output connected.
My installer said that due to not being able to guarantee the earth connection I was told I would need an earth stake and cabling on my property to satisfy wiring regulations.
For this and the other associated work required my installer said that the bill for this extra work would be around £1000. When I was looking for quotes for my PV system I started by looking at the MCS website which can show via a Google Map the installers around you geographicially who will have gone through a few more hoops to get the MCS certification.
Hope this info is useful to you.
In the US NEC has required rapid shutdown systems which micro-inverters, or DC optimizers provide that functionality. The cost of buying a DC optimizer is only about $$10 more than a rapid shutdown module. That is something to consider most local city inspections will require that rapid shutdown switch. Ground mounted systems don't require the rapid shutdown switch only rooftop.
Thanks for this info - rapid shutdown is likely to become a concern in other parts of the world as well
Super impressed with your solar video series. I'm in the process of deciding on my own solar set up and found your video on microinverters and optimisers very useful. I agree with your conclusion and will not be going that route. Can you recommend an installer who installs the Perlight Delta shingled panels you chose?
Thanks for the kind words, Paul - and I’m very happy to hear that my videos have been so helpful to you.
Now, most installers should be able to get hold of those panels are they’re quite popular. Just specify that you’re looking for those particular ones. Good luck!
Thank you for sharing this. I’m considering adding bifacial solar to an arch at the stern of a sailboat as reflections from the sea and the boat might improve the overall wattage. I would appreciate your thoughts on the matter. Thanks.
Hi Frank - you're most welcome. Now, I'm not in a position to comment on this, as it's not an area of expertise, but perhaps others can... :-)
Thanks for the mice video! I decided to not to waste money on optimizers.
Hi Muhammed, you're very welcome - great to get feedback like this! And yeah, if you don't have any shading, or only hard shading in places, then optimisers are unlikely to add a lot of value.
Thank you!! Greate video i found all my rpoblems in this video!!
Great stuff! :-)
Is there any research about improving output in cloudy weather. And Awesome! Finally i got answers on many questions
Thanks for the kind words, Oleksandr.
Now, power generation from solar panels is all about the amount of light hitting them. And unfortunately, cloudy days mean less light. And less light means less power generation.
The only solution is to improve the efficiency of solar panels. Today, they’re just over 20% efficient - but the great news is that efficiency is increasing over time as new materials and manufacturing processes and brought to bear 👍🏻
@@GaryDoesSolar
You are right, but my question was mostly about string sizing, I do have 7kwt installation (18 panels x 390w 40.8Voc 33.8Vmpp ) and noticed that generation starts from 600v on panels so was thinking that my installation is not optimal but now I have realized that 600V is optimal voltage for my inverter's mppt and when generation starts it starts from that optimal voltage. So adding panels in that string will probably makes no difference is it correct way of thinking? Or if I will add panels to the inverter string and keep it to maximum possible (1000v in my case) it will reach that optimum voltage faster and start generation even with less light from sky?
Hi Oleksandr, I think you're best to have a qualified installer answer that question as that's not my area of expertise I'm afraid...
Hi Gary, a very insightful video and indeed your entire series are a must watch for anyone considering PV install.
I am looking in to PV and I do have a three aspect array requirement East / West - Main House roof and South facing detached garage.
We do have shading and tree issues (more pronounced in the winter - lower sun angle) so I originally thought I would be installing a Solar Edge optimiser based system, complete with 400w mono black Half- Cell panels, but I must say I am now rethinking it after watching your video, perhaps changing to Shingled design panels?
I can't seem to find a three MPPT inverter in the Solar edge range, perhaps It is just not an option?
I also looked into the Perlight delta 400w Shingled panels, and they look very good, but perhaps the Hyundai 400w Shingled Panel, which has a 25 year product /25 year performance warranty, seems to trump the Perlight delta 15 year product / 25 year performance warranty?
Although the Perlight delta is a more efficient panel (21.3% for the Perlight Delta Vs 20.4% for the Hyundai) perhaps this swayed your choice?
Are these the only Shingled PV 400w panels available in the UK currently? I couldn't find anything else.
Thanks for the kind words, Ade. And great to hear that I've got you thinking about your installation options :-) Worth checking on sites like below for any shingled panels:
midsummerwholesale.co.uk/buy/perlight-monocrystalline-solar-panels
solarsuppliesuk.co.uk/product-category/solar-pv/solar-panels/
Great video
Thank you! :-)
Hello Gary! I love your videos!
Quick question - for "triangular" shading situation (example terrace wall or half wall on roof), that would cover a triangle from left lower corner of panel towards the middle of the panel on the right side.
What would be the best solution? A shingled panel? Some different managment approach? Could you mix different panel variations due to shading issues, but considering all of the panels having the same specs? Sorry for the long question,thank you in advance! :)
Crikey - lots of questions! :-) So for triangular shading, you're likely tripping 2 of the 3 bypass diodes in a typical non-shingled panel. I can't answer easily for a shingled panel, but they're all laid out in different ways, but I suspect it's not going to be too different - you might only get a 3rd of the maximum output. I wouldn't recommend mixing panel specs on the same string as this can give additional issues.
Thanks for the video Gary. I'm not sure I really understood the split panel mptt optimisation, a single panel is easy to follow, but surely with an array of panels if it used half the voltage that would decrease the overall output significantly? It must find an optimum point, but the diodes are either open of closed and I'm thinking that will always be closed so no advantage?
Hi Stephen, you're most welcome. Yeah, the way I like to think about MPPT, is that it appears an intelligent process but it's not. The MPPT controller in a string inverter simply adjusts the voltage from 0 upwards (a sweep) every minute or so, to see which voltage gives the highest current, and therefore the highest power. It doesn't know about bypass diodes or even optimisers, how they work or anything. The problem for the string inverter MPPT controller is that if there is shading only on one panel, it can't really do anything to optimise that because it will surely bring down the current on all the other panels, so in reality, it's only effective if all of the panels in that string have exactly the same kind of shading (say the lower half of each panel shaded by an adjacent building later in the afternoon). In my mind, these conditions are rare, really, what is the increased generation advantage? Interested in your thoughts on this...
@@GaryDoesSolar Definitely sounds rare in a string, but with an optimiser per panel it’s perhaps a further option when all 3 sections have shading on one half. I expect there are other benefits of the split panel, as this one sounds quite marginal. It would seem like smarter electronics in a panel could handle shading better than diodes, but perhaps it’s avoided due to generating heat.
I have panels going up tomorrow with a little shading from a chimney, I’ve gone against my installers advice and will try without optimisers and just position the panels away and accept some loss, my feeling is that shadow is only a factor when there is direct sun, and that’s less common anyway later in the year when shadows are longer. It’s an EW roof with a 40 degree tilt so the only months where the sun is high enough to reach the other side limit the shadow length. I wish I could do 3D trig to properly work it out, but alas beyond my maths ability.
@@smc812 Hope all goes well with the installation - and I reckon you'll be fine not having the optimisers given what you say. And there's still plenty of summer left for some nice generation 🙂
Thanks for the Video Gary. When you are saying "Inverter" are you talking about micro inverters only or string inverters as well? I have half cut panels with bypass diodes with an all in one MPPT string inverter.
You're most welcome. Yeah, it can get confusing between "inverter" and "microinverter". So, in my videos, if I just say "inverter" I'm always referring to a string inverter. Hope this helps!
Thanks for the great summary - your channel is really helping me to make some decisions about the system I will install. One question... whilst the panels do a good job of managing shading within an individual panel (especially half-cell panels), won't any shaded panels still limit the power output of all other cells in the string? So if you have a single string of 10 panels with only one that is are partially shaded you are losing quite a lot of power compared to using micro intervers where all non-shaded cells work at full power. Is that correct?
You're very welcome. My analysis tells me it depends on the kind of shading in fact:
If it's hard shading (like from another building) then the bypass diodes are pretty good at limiting the effects only to the panels that are shaded - the other non-shaded panels will operate without problem.
If it's a large amount of diffuse shading (limiting light to say more than 20% of the panel) then it's as above - the bypass diodes will do their job.
But if it's a small amount of diffuse shading (limiting light to say less than 20% of the panel) or if there is shading from a cable or antenna, then the bypass diodes might not be triggered meaning current flow will be limited in the other non-shaded panels as well.
I am using powerwall3 which allows upto 6 strings input.
I have two arrays. A 8 panel array in prime sun location. The second array is 16 panels that is effected by tree shading during early morning and mid day. Without using optimizers or microinvertors. Would it be more efficient to have 3 strings on the large array instead of just one large string?
As you show that shade or issues with one panel will effect all panels in the same array string.
Without knowing more detail about your situation, I’m not in a position to advise. Best to contact a local solar installer for guidance.
Very useful! Currently researching what solution to get, and certainly, SolarEdge are very popular - but seeing the reliability review from MC Electrical gives me pause. That said, the review is a few years old now, and Mark admits in more recent comments that he hasn't gone back to the product to see if things have changed.
So, it's off to Trustpilot to see if there's some insights to be had there. MC Electrical seem to rate Fronius highly - but there aren't many reviews on TP to make a solid judgement. However, the reviews that do show up there, are largely negative.
SolarEdge don't do especially well either on TP, albeit they have more positive reviews than many of their competitors. If that's 'the best' I can get in terms of customer service though, then it's still enticing, even if I don't technically need the 'benefits' of optimisers, and could be risking additional failure points. It's all about whether I'll be looked after if those problems occur.
Still, lots more research to do!
Great to hear you're getting a lot from my videos! Yeah, it's quite a minefield choosing the right solar solution - good luck in your journey!
Hi Garry great video but feel you have missed some other benefits of microinvertors.
You note in video if microinvertor shows issue you can not resolve it.
I had a failure and I used the ABB powerone microiinver to reboot and repair microinvertor.
You can update microinvertor softwar and change standards as standards evolve. Ours changed and microinver software covered change.
If say panel fails I don’t loose string and I actually know which panel failed. We have 20 panels so we loose 1/20 or 5%. Where as string could be effected and you don’t know which is effected panel.
Power from microinvertors is cooler as wash is just converting power at lower domestic voltage and ours is 230 volts + or - 10%.
So as you noted growing system is easy.
But other feature you missed is string connection to main inverter is high voltage hotter connection and a number of fires in Australia were identified as isolation solar switch arching.
As each panel has microinverter there is no main inverter to place so installation is quicker and placement of inverter is not an issue.
Main inverter run hot and have say 15 year like. As they day you loose all power or one phase. But as microinvertor is running cooler life is longer but as failure occur it will be a unit in many so solar is continued to be generated.
I learnt a bit about the improvement in solar cell shading features as our system in circa 2014.
So much in 1/2 cell and shingle is new to me as we are not in the market to replace.
Thanks for your comments, Malcolm. This is great insight!
Great pair of videos. If you are choosing a panel because of its warranty, how will you know that one of say 20 - 30 panels has fallen to say 85% of rated output when it should be 90%, without optimisers.
In the 1st video you said the optimiser could cost as much as a panel. I would like to see a half decent $80 panel, because that is what the Tigos cost here in Australia, or Huawei at about $65-70. THe Huawei optimisers are warranted for 25 years I understand.
Hi double-x :-) thanks for taking the time to comment on my shading videos - very much appreciated! Now, you raise a good point. Without any kind of monitoring, how would you know? And without any panel-based MPPT (either via optimisers or microinverters) how would your system ensure that those panels which have deteriorated the worst, don't bring down production of the others? I mean, it all points to the argument of *having* optimisers/microinverters, but I worry about their reliability, which could end up costing you more than they're saving...
That said, I do think there is a case for microinverters as the key to mass adoption of solar - something I'm making a video on shortly...
With regard to pricing, your point is valid (wrt optimisers) - they're relatively inexpensive now - although I do believe you have to buy a separate monitoring unit for the array as well?
Hi Garry
Just a quick question. Do you have any update on the Tigo optimiser problems outlined by Mark in his blog post?. I have just recieved the design for my system from the installer and they want to use Tigo to handle the East /West split. Im just wondering if we will need the monitering system to make them work.
Simon
Hi Simon, I have been in touch with Mark but no updates as yet, sorry. Good luck with your solar installation!
@@GaryDoesSolar Hi Garry. Thanks for the quick reply. I have decided to get the monitoring system as the price is relitively small compared to the whole system, And if you have these things you might as well know what is going on up there!!
Hi Gary. Excellent video. I don’t get if I had panels on west and east on same string then given panel’s built in bypass diodes then it should handle the shade (or less sunlight) on west panels in the morning while full generation on east and vice versa in the afternoon. I say I don’t get it because you mention in the video that optimzers are needed if panels on same string face different directions
Thanks for the great feedback! Now, the problem comes from the fact that ALL the panels on your West roof will not be generating much in the morning , whereas ALL the panels on your East roof will be generating a lot (assuming a sunny day). The bypass diodes won't be able to handle that mismatch very well. You're far better putting each orientation on its own string as opposed to adding optimisers. Optimisers (and microinverters) work best when there is partial shading within a single orientation.
@@GaryDoesSolar thanks for your reply. I was confused about your video which illustrated it as a bent hose with the current being pulled down by the panels on different orientation - is that indeed true as it would seem to be contrary in my mind with your other examples that indicate if panell(s) are fully shaded and are on the same string, it would not effect power output from other panels; therefore I was assuming in a situation with panels on different orientation but same string could be modelled as simply panels with a lot of shade on them when sun is on the opposite side; does that make sense or am i missing something fundamental in my understanding ?
@@warperone The problem here is that the panels on the East and West roofs are never shaded as such - they're just not seeing direct sun at different times of the day. There is still a lot of ambient light around, and bypass diodes are designed only to manage partial shade.