* NOTES SINCE RELEASE * I've been informed that some of the most recent inverters have a very flat efficiency curve that only seems to fall away 5% of the inverter rating. I don't yet have any sources to confirm this, but would welcome if you hear of any.
Gary, you'll never get the views you deserve. Stripping naked on instagram, you might ! I think your YT activities help you to sort your thoughts, and you should leverage your work through consulting, or even designing installations for others.@@GaryDoesSolar
I agree. Looking into this and I didn’t realise there was more to this. I feel scared to install solar now in case I make a wrong or less than best decision. I’ve got so many upgrade paths with replacing pool solar and upgrade to battery in future. I feel I could mess this up. Is there good system which exists to cool panels ? Sprinkler or use pool water pump ?
WOW I cant beliive this video has come out today, my system has come online today and my installer recommend a 6KW inverter for my 8.1 kw total panels and 10.5 kW battery system and this video has proved him right.
We recently installed 31kWp of panels for a house which only had a single phase supply and therefore a limit of 17kW could be connected to the grid, but we were able to use 17kW of SolarEdge inverters and oversize, works really well!
Wow - that's impressive! And it's great to see Artisan Electrics continually demonstrate their immense knowledge and expertise in all the videos you make: th-cam.com/channels/UYJhbsrC1bvVWzgUq83K4A.html
How did you get away with amount of power on single phase? when you are export limited. Here in NZ max export on single phase is only 5kW now. This what has happened in Aussie, too much solar and they have restrictions placed on them now, with lines companies having control and shutting down the PV system using the DRM bulit into the inverters now.
great easy video! another positive thing with oversize array is reaching faster the minimum input voltage of the invertor so that helps getting more solarhours usefull
Thank you :-) I did think about adding in about an oversized array meeting the start-up voltage quicker, but actually I don't think it makes that much of a difference to overall generation. I don't have data to show that though - perhaps someone else has....
There is a misconception about the minimum voltage. The panel voltage is not influenced by solar input, only by temperature. In the morning/evening with little sun input the inverter can have trouble starting up, but that’s solely because of the minimal current needed by the inverter, not because of low voltage.
@@SanneHoekstrathanks for that clarification as I was trying to work out how many panels to have in series/parallel. My preference is to parallel panels rather than use optimisers or micro inverters.
@@jameswestcott4191 I’m not a solar installer, just have some electrical background. I would be very careful with parallel solar panels. In that case you have to add up the maximum amperage, that is a bigger fire risk and you would need way thicker wires. I would stick with a series install. Unless you have much shade, you don’t really need optimizers, all panels have bypass diodes to make sure your install will keep working even with some shade now and then.
Well done! The only thing I think you missed was that oversizing the array also changes the shape of the curve (same orientation) by allowing more production earlier and later in the day, as well as in cloudy conditions. Basically it will produce more earlier and later, adding to total output or area under the curve...
I agree, it's not about voltage but more about current. So for the same "light energy " more current is available from the array. So the larger array will have a different shape curve.
@@caritechsolutions9382 Exactly! All things being equal, at any given time the oversized array will make more power, other than when the inverter is clipping at max output. So if you imagine the std array is putting out say 1000W at a say 8AM, the larger array that's 50% larger will be putting out 1500W. This is cumulatively a pretty significant difference and greatly increases the area under the curve if you were to use your diagrams.
Thank you so much Gary. I have only just discovered your channel with this video. I installed a 5kw array with 5kw inverter a few years ago. My needs have changed dramatically since then. I now have an EV and battery and combined with a pool pump and upcoming heat pump install my system can no longer cope. I’ve been trying to find an inexpensive fix and your video has been a God send. I did not know this was a thing. Oversizing!!!! Wow. I’m a man on a mission now. Many thanks again. I’m now an avid fan and subscriber. So many more of your videos need watching.
I’m planning my own system, and currently working on sizing based on the system input, and panel configuration. I had come to the same conclusion to over-provision on the PV side, and this video further confirms this industry standard practice. I’ve been playing around with a single 100W and 400W panel as a proof of concept, and I’ve personally seen examples of everything you’ve described. Thanks!
What you described is probably the solution with the highest possible available financial ROI at the moment. We need to supply power in the morning and evening (see duck curve). We do this by placing panels east-west, not toward the equator. It matters little if your setup harvests relatively less power around noon, because power will often be cheap if not free or negatively priced at that moment anyway. Oversizing works especially well if panels are cheap and inverters are expensive, which seems to be the case. I heard from a source that I consider reliable that panels HALVED in price over the last year. Prices of inverters seem to have changed very little over the same time period. NB: It’s important to look at your *actual* expected peak power. 25 panels of 400 Wp each placed east-west probably won’t ever actually produce 10 kW, especially if you’re farther from the equator. If you have a DC-coupled battery you can get even more power out of your inverter.
Very interesting , good for you .More people will take up solar when they see simplistic explanations of the solar power available . I installed 28x 400w panels at latitude angle with 2x 6000ES + inverters and 3x 9.6kw Li batteries . The result is an abundance of power on a daily basis . The system has been running for 20 months now and I am always looking for more appliances too use up the surplus. 1 inverter had a charging failure which meant that the 2nd inverter had to handle all the charging and loads . It coped well with this , thus qualifying your ( and my ) theory on over panelling . Panels have never been cheaper I encourage those looking into a PV system to add more panels than the energy audit suggests .
Really useful information, thank you! We recently had a 7kW array installed with a 6kW inverter 10kWh SolarEdge battery. I wondered how the battery was able to take 5kW while still exporting 2kW to the grid and this video answered it (the battery is DC coupled). Also watched the video about batteries too. Excellent information really clearly communicated. It's hard to find this level of technical detail without the information being hard to understand.
It was interesting hearing the solar energy requirements in the UK. In the US, most inverters for residential use are sized around 15kw with many being twice that size. A 3kw inverter would be something you would choose for a tiny off-grid cabin. My local utility sets a maximum of 17kw for a grid tied solar system.
Thanks Gary, I must admit I thought i knew what you were going to say and I got some of it right, but you made many more points than I expected.. Excellent video content and delivery.
Thanks. And great to hear you're already well up on the topic! Hope the video helps a lot of people when deciding what size of array and inverter... :-)
Gary, Thank you for another fine video. Two years ago I increased my system from 12 kW to 15 kW in anticipation of my purchase of an EV. I did this on the recommendation of my excellent solar contractor/electrician. Since my SolarEdge inverter is 10 kW I’ve been wondering if the oversizing contributed to the premature failure of the inverter. You read my mind and put that concern to rest.
It pays to know the product before adding more panels. Usually there is a spec that says maximum amps allowed from the PV and it will be a bit beyond the normal operating range. Don't exceed that rating. Particularly for chargers (standalone or inverter/chargers) the better ones will detect over voltage on the battery side and can take action to force charging current off hard by shorting the PV to handle situations where the charging circuit fails and supplies uncontrolled current to the battery system. Even the ones that have PV relays can have this. Too many amps = damaged 'shorting circuit' and all the possible failure modes that stem from that.
I did this without realising. Managed to get another 3 panels on,y Tony roof in landscape, on top of the rest in portrait. It’s really made a difference. Next looking to get some on the back roof even through it’s north east facing, maybe 4 more, and then add the batteries. While my export rate is great here in Ireland at 29c a unit, it’s dropping more and more. So batteries with extra panels make more sense.
Thanks Chas :-) Yeah, I'm trying to incrementally improve aspects with each video - hard work but worth it! Glad you like the T-shirt - the reason I got one is really so I don't have to spend time choosing what I'm going to wear for a video! Lol
Another super interesting informative video Gary. I oversized my array, 9.6kW on a 7kW inverter and 9.4kW battery split across two roofs. So makes alot of sense to maximise generation from the roof space we have without a bigger inverter
This is a great video and extremely informative well scripted, videography was great and the information was accurate and well spoken to the targeted audience. Also it highlights some of the issues I have with solar power being pushed so hard. Firstly I think that solar is a wonderful thing there is no argument there at all, none, however storage is less than optimal and expensive. Then the very folks (read the government) that push the solar alternative charge you exorbitant fees to add solar above some prescribed rating to your home. Then the insult to that injury is that the folks that push the solar (read the government) on you regulate the amount of income you can receive from the power company for excess electricity that you, using the equipment bought, paid for and installed by you, kindly sell back to the grid for your neighbors usage. If you step back and take a zoomed out view, instead of the myopic view of solar is so great and I am doing something great for the planet, then you can see that something is just not right at all with the "solar plan" the government makes, if it is needed so badly why charge crazy fees for the licensing above a certain size, the licensing for the installation, the taxes on the equipment and taxs and fees for the re-selling back to the grid? And yes I understand the need for electrical qualified electrical installations that are inspected by those very folks. (read the government) (humor here). Where I live there are no restrictions for solar you can add as much as your wallet allows, but I used 390 kwh of electricity last month so my 50 dollar electric bill does not make me want to install $10k worth of solar panels, inverter, solar battery managers and batteries to drop the grid. The perfect solution was fielded by Musk at one time, electrical co-ops, where you and nine other neighbors (10 being an arbitrary number) were the entire 'grid' for yourselves. 10 homes with this oversized solar like in the video, a centralized 10 Powerwall system and 10 inverters, one in each home. No power back the real grid, and everyone shares the benefits and the costs.
UK NW England. Install on SE facing roof. System: 6.2KWp + 5KW inverter + 13KWh battery. Had to hand £600 to DNO for sign off, but otherwise happy. We generate 6MWh/year. Good analysis. More winter power when you really need it. In summer too much power to use.
Found this excellent channel today. Going to be 8k inv 12k solar ratio in a month. All my upgrades this month are engineered for winter production, 2x 2790w to 3255w, and a new 3300 array PV2 remains at 2790w. As a whole 8370w to 12600w, the 2790's have peaked at 3514w (vertical bifacial) with this set up I expect the 3300 will max at 4000. Overcast winter estimate 3200 watts total and should give me the 14.6 kw I use daily. I dealt with 105 days of overcast and fog. November 2023, 4 hours direct sun for the month, December was 8hrs and January at 13 hours, 3 months 25 hours of direct sun. My inverter was silent for months. In heavy overcast pv2 a 2790 array produces a minimum of 580 watts. Bi facial panels are mini black holes.
@@GaryDoesSolar It seems the 2nd inverter was showing inflated pv values on pv1 and 2 it was producing different #'s with the same array switching inputs. My solar dealer drove 8 hours to do a free upgrade to a amen 10kw, same as NHX10, all my data flawed, looks like the 580w from pv2 is actually 380w in heavy rain. So far I cannot get any data using 6kw a day the pv is clipping from sunrise.
Great video and very well explained. However a roof has a load maximum based on the set up of the roof, the tiles used, then the additional weight of the mounting system, panels and any snow predicted for that area. Whilst it makes sense to do oversize the array if you can, ensure a weight load is carried out on the structure of the building to ensure the roof is capable of taking the extra load.
Interesting video. Had solar for 13 years now great investment. One thing you didn’t mention the other big killer is temperature. Cold sunny day in December can giver way more peak than you would expect where as peak output an a 33 deg day can be disappointing. Last year on the 40 deg days power was way down.
😊 This is the 1st video of yours I've seen. Very interesting. I'd like to learn what ever difference there woukd be if not a house. But a flat roof recreational vehicle. In the US, there isn't a rule saying you can't take a solar array to the edges of an rv roof. But, for the most part, they are going to be parallel to the ground. Don't think there is any restrictions on sizing an inverter on an rv either.
Thanks, Edward. Now I don’t know too much about the intricacies of flat roof installations in RVs etc. but I’d imagine there will be people out there on TH-cam with videos on that 👍🏻
Another great video Gary, thanks. My array is 6.8kWp on a 5kVA (4.4kW) inverter (55% oversized) and tbh I would have installed more PV capacity if I could have fitted it on my roof. It's a DC coupled Victron system with 14.4kWh of Pylontech batteries so I can avoid clipping most of the time. I'm also based in central Scotland and although my roof is facing 184 degrees, the pitch is just 14 degrees so it's unlikely I would see 6.8kW from the array even in summer. So far I've seen 6.3kW max in mid July so I hope to see a bit more than that in late May or early June but I doubt I'll see 6.8kW. In fact my Victron MPPT charge controllers are 250/60 units (2 of them) and although they are spec'd at 3440w each, with my charge voltage of 53.2V, my theoretical max would be something like 6384w total (53.2*60*2). I am considering adding an AC coupled non-hybrid inverter with four or five 435w panels mounted vertically to my south facing garage wall as a "winter array" to boost my generation. This would be a more cost effective way to add some extra capacity for the winter months than adding another MPPT and having to run DC cabling all the way back to my inverter and battery location. I could just hook it up to the garage consumer unit instead. I might even add a few extra panels to the east and west gables of the garage and use optimisers to allow them to work with a single inverter. A project for later in the year I think. :)
Thanks for sharing this info about your system, Craig - sounds great! And always a good thing to add more panels if you’re able - all the best with it 👍🏻
Thank you very much, Gary. Your videos are the best classes on TH-cam on this subject. I would like to take this opportunity to send a question: Do you think that adjusting the tilt of the panels, to maximize winter production, could be a good strategy to minimize clipping on an inverter overloaded by 150%? Would this strategy bring more overall efficiency? I haven't been able to find studies on this strategy yet...
Thanks very much for this great feedback - very much appreciated :-) Now, are you talking about a ground array (easier to change the tilt twice a year, say) or a roof mount (all sorts of complications including access)?
Shot in the dark, Have you ever looked into wind and solar as an option? I've just had solar installed to provide energy to our property and I'm just starting to experiment with a small turbine to provide power to my workshop albeit just lighting for now.
Hi Graham, now, wind generation is certainly an option that many are starting to look at, to compliment solar. But (unfortunately) there are a number of factors that limit it’s viability in consumer applications: - Wind turbines are not quiet - worse, the noise varies with the wind strength, could drive any neighbours close by insane. - They are also nothing like solar panels in terms of reliability - you might find you’re spending a fair amount of time, money and effort keeping them going. - And they’re expensive. Like really expensive for one that generates even just a few kW. - Also watch out for the advertising. Some retailers talk in terms of kW (power) when they’re actually taking about kWh (energy) - even a cheap 30cm diameter turbine will generate 20kWh given enough time!
well said, brother... I'm kinda new at this solar thing, and I had a hunch that getting the max output of power was literally - a moving target. On "paper" it's a static number, but in real-life, there are many variables and most of them are in constant movement. Kinda like going duck hunting with a bee-bee gun and not a shot gun. Greg (garden grove, CA)
Hi Greg - thank you for taking the time to comment, and glad that my videos are useful to you! You're not wrong about trying calculate max power - haha!
I've a 6kw Solis inverter and 18 PV 370 watt Panels, is that over sized,had 14 Panels last year,but had the extra ones fitted this month, seams to be a improvement in generation on the odd days we've had a bit of Sun 🌞
Perfect - we do exactly the same on a DC coupled system mainly for winter shortfall (adjustable array), just be a bit careful as summer yields even inthe the UK, can be 10x what you expect, so stuff can get very hot quickly - we may do a G99 as currently just do off-grid - but even with OE at 15p/Kwh export (upto £1k / pa????), i'm not sure that its worthwhile? - having said all this I'm just configuring my system for VE Dynamic ESS (and G99 approval) for possible use with OE
At 6:30m you exactly describe what I want to do. And I have a SOLAREDGE setup with exact that configuration and a DC-battery. Except for : it does-not-work ! The system ignores the charging/decharging time table completely. Even discharges the battery a few percent under the set minimum backup, ánd imports energy from the grid what I blocked in the settings to bring it back to '40%' after discharging to 38%. And it continues to cahrge/discharge throughout the night..
@@GaryDoesSolar My app gives the options for opimised self use/sceduled/backup. I contacted SE and they reply the problem is that I have three inverters.. .. which is nonsense as they are independent systems, one is even in another building in my ground. Batteries directly intalled with hybrid-inverter. Installer comes by next week checking all devices for updates.
I've oversized my system and designed it around winter. I've got 3 x more panels than my charge controllers can process. I've designed it for dark and cloudy days. So high voltage strings in parallel, to get the most from Mppt. I built a ground array facing south. I live offgrid in Sweden. I've got my panels aimed for the winter sun. Also, the steep angle helps keep snow off, but after every snow fall I still need to go out and scrape off snow. That saying, in the sommer my batteries are usually full by the time I get up in the morning. I'm not worried about the bad solar panel sommer angle as I have such long daylight hours. Also in sommer I turn off most of my strings. I run 12V for everything, but have a 3kW inverter I can put on when I need, mostly for the washing machine, (always run with only cold water and 40min cycle) It works for me.
Hello. Did you say you have 3x the amount of panels for your charger? I thought each string has a max amount of input from panels coming in and to not go over that amount or it will compromise the inverters performance? What do you say on this Gary? Also, greenbymoon, what brand and size inverters do you have with how many panels in what wattage? Thank you.
@@lindaferguson593 I don't have a permanent inverter running, as I'm using a full 12V system for everything in my offgrid house, which is about 40m². I have a Giandel 4000w 12V Pure Sine Wave Inverter I use to run my washing machine for 28 min about every 10 days when I have sunlight. I have 18, 335W solar panels set up in 3 parallel and 5 strings, each string on its own DC circuit breaker. I have all turned on during what I call the dark season here in Sweden, Oct to end Dec. Then the snow falls and albedo effect starts making a big difference. I start turning off strings as my light level increases, in Sommer I run just 1 string and my battery is full when I wake. I get sunlight in sommer from 0300 to 2300. Winter 0900 to 1430
Agree with all the point you make Gary, except for the one about dirty panels reducing power output. My own personal experience, I’ve had a 4kW FIT array since 2016. Every year annual generation has been around 3mW, some years more, some years less. I’ve seen no obvious degradation due to dirty panels (or panel ageing); the panels had never been cleaned until last January when we had scaffolding up to install our new 10kW array. There was a bit of lichen in a couple of spots but the panels were pretty clean considering. I’ve read that they do generally keep themselves clean with rain and wind, and that’s been my experience. Of course if you’re heavily overshadowed by trees or birds dropping on the panels then yes a potential issue, but then you’ve got other shading problems as well
Dirty panels is not a problem in the wet and windy UK, here in southern Spain we have a lot of dust, and rarely sand laden rain from north Afrika and very little rain at other times
That’s great, Geoffrey - and I’m noticing the same with my panels. I thought I’d have to clean them regularly (bird mess etc.) but with the regular rain, the panels self-clean 😀 Countries with less rain might have a dust issue over time though…
Yes fair comment about dusty and less rainy countries. I was thinking from personal wet UK experience. But to caveat the "no issue with dirty panels message", when we had the extra panels fitted last year, as they filled in the gaps on the rear roof, one new panel was underneath the TV aerial and within a couple of weeks the panel was covered in bird poo. Had to go up on the roof, fit bird spikes and wash the panel
@@Riceman-o1p there seems to be plenty of websites explaining what a megawatt hour is. I should have written it as 3MWh though (capital M). I wrote it that way because it makes me feel like a big electricity generator 🤣 3000kWh is just as good
Hi Gary, Thanks, that's very informative. Re the inverter efficiency @5:00, are there figures for this? Also, AIUI inverters with different AC output ratings may have the same internal DC capability. I'm thinking of the GivEnergy Hybrids where 3.6 and 5kW inverters both have the same 7.5KW DC capability, so they can simultaneously export 3.6kW AC and charge a DC battery. Presumably the efficiency of these would be identical?
You're very welcome. I don't have efficiency figures myself (just statements from inverter manufacturers that I've read). Your final question is a good one to ask on a GivEnergy forum...
I thought that was very helpful though it is less easy to see how running two arrays pointed differently would impact on your overall generation and the extent to which you can over-provide capacity against the inverter limit.
Hi Rhian, I developed a utility that you can carry out some modelling on. It's not free, but I've kept the costs quite low: www.garydoessolar.com/solarazma_pro_intro/
Hi Gary, you have brilliant videos and it's nice to get it from a UK very knowlegable source as opposed to the reams of mainly American DIY vids. I was just wondering, if you are not trying to reduce bills by feeding back to the grid , is it possible in the Uk to have a connection to your house by a change over switch set up a bit like a generator plug in point where you can either feed your house from the grid OR feed your house from your solar inverter in a way that it would be impossible to send solar generated power into the grid. ie, one or the other without the hassle of G98 / G99 acreditation.
Thanks for your kind words re my videos - that's such great feedback! :-) To your question, unfortunately, not. Any changes to a residential property's electrical system wrt renewables must be G98/G99 certified.
Thanks thinking about making the jump your videos are very informative, can I ask what does this mean for a enphase your system with microinveterrs and AC system + battery
You're most welcome - thank you for the kind words :-) See my comment to @andyb8268 next to yours. Enphase wants me to interview them for a video shortly, so I'll try to cover this with a question...
Hi Gary,thanks great video.Can you maybe enlighten me,what is the solar maximum size on a 5kw inverter,as i understand the voltage is the biggest issue.Will apreciatre your input.Im from South Africa
So, this is a question you'll need to ask the inverter manufacturer or your installer, as they're all different. Thanks for the kind words about the video :-)
Hi Gary thanks for the reply,i actually want to know,i have a deye 5kw and it states that the max pv is 6500w,17amp.What i wanna know does it matter if i use 550w panel,that panels state that it has a cs amps of 13.Will this be fine for the inverter?
@@johanerasmus6721 Thanks for supplying the extra detail. This is definitely a question for your installer, I'm afraid. It's not one I can answer, sorry :-(
Thx a lot nice videos lots of learning however can you highlight can we consider inveters which allows overloading upto 50% and post same can we say oversizing concern is resolved thx.
Thanks for the kind words about the channel. I'd love to do all these things and more, but I'm just one guy currently with a fairly intense day job, so it's very difficult to find the time... I'd love to do solar stuff full time one day though... let's see what happens... :-)
5:50 east west is nice as most inverters are dual mppt input so each side,note there is now g99 fast track if under 7.6kw ish (32amps) usually approval time is much shorter (The general issue is a lot of solar installers won’t do it because they just wanna make quick money)
@@GaryDoesSolar as long as its not more then 32A (7.6kw clipped inverter I think) it's usually less then 30 days (unfortunately some DNOs are not as nice to work with for g99 and force a 16A g100 device so you need battery storage system to get the most out of your install) might be more hops if it's past 32A total install and max total generation is 60A per phase if you have Mutiple inverters (usually require a g100 limiting device so generation power can be cut off when DNO requires it) If you look for g99 fast track + your area DNO there are quite a number of sites when looking for installers including g99 in search should filter it down to a smaller amount installers who are willing to work with DNO to submit the correct paper work
Greetings. Congrats for the video. I didn't know the benefits of oversizing. I was amazed. I have a growatt spf 6000 es plus. Now I have 12 sunket stk410M10 panels in series for One MPPT. If I don't bother you, can you tell me how many panels I can install at most? I'm sorry for the bad English. Google. Translator Greetings from Italy
Thank you - you're most welcome! Unfortunately, I'm not set up to provide individual advice, but it's worth you reaching out to an installer and getting their view on what you'd like to do...
In my country you only get the government grant if you export less than 20% of the energy produced. Over-sizing can get you in trouble. Since I stop working from home and bought more efficient appliances I'm finding harder to consume all that electricity, by this summer I guess I'll have the car plug in everyday to use that 80%
Hi Samu, which country is that? I guess they don't want to much export then! And yeah, it puts a lot of pressure on you to try and consume all that energy!
Absolutely correct, even with microinverters. The peak is clipped but area under the curve is still larger. The objection of course is the higher initial cost but ROI could be quicker.
The lower limit on UK setups without jumping through a load of hoops is crazy. Almost like they don't want people to make the most of the products available. Is it allowable to have one 'on grid' and one 'off grid' setup that don't overlap at all?
We have 6.4kWp panels feeding a 5kW Solar Edge inverter with Tesla Powerwall 2. The inverter frequently clips during summer, and every time I look at that flat-topped curve I can't help but wish we had gone for a 6kW inverter. It would have cost little more and given us more energy.
100% Brilliant Video 1. Take your Roof Size and work out what is best for your size of roof, dont just go for the biggest wattage panels as the physical panel size might mean installing a lower watt panel would mean more panels i.e. 10x450w panels is 15sq m but having 15x400w panels is also 15sq m but the lower wattage panels would actually give you a higher peak. which is higher early morning and higher late afternoon. 2. Solar clipping is never expanded on enough in my opinion especially in a country like the UK which is rare to have peak production so having more panels/larger array means more kw production. 3. I even prefer micro invertors so even when clouds partially cover some panels the other panels are still producing maximum 4. Oversizing also allows for panel degradation. A panel typically loses 1% in the 1st year and lets say 0.5% each year there after, over sizing means in 20 years your system is still performing like the 1st day you installed it. 5. Oversizing - Also possible you can also "clip" your export too (Export Limiter), so if you have batteries/or not and are producing 6kw you can charge all this 6kw to your batteries when they are full you will then only export at 3.68Kw; again the full 3.68kw for longer due to the clipping. Or your producing 6kw using 3kw in your house and exporting 3kw (saving and making you money). The cost of panels is now relatively cheap, by this i mean if your installing 10 adding a few more is not a huge cost. This is one of the best videos i have seen that explains Oversizing/clipping. When i designed my own solar array i even found a white paper from "Enphase" showing the advantages of doing this but it was pages and pages of numbers and graphs; being a geek i took to it, but thought how can "Joe Bloggs" be expected to understand this stuff. They just want to know what does it cost and when will it pay for itself/make me money. Also the downside for a Solar company that would quote a larger oversized system would be more expensive than someone who didn't so i feel for them too.
Thanks for your video Gary; very informative. Pardon me but I am a total noob who has just had his first Sunsynk 8kw installed at his home. I heard the installers speak about the voltage limit on the inbuilt dual MPPTs as something that will limit the size of our array to around 8,4kw. The MPPT are apparently limited to 450v and the array cannot exceed that per string. Can you be kind enough to comment on that?
You're most welcome. Now, I don't have any experience of SunSynk equipment, but it's worth signing up to this Facebook group, where you could ask those kinds of questions. Lots of support there... good luck! facebook.com/groups/571819024654208
Hi Gary, I'm a Gary too. We're building a house shortly. Unfortunately being on a lake, view is determining position of the home over Solar. That said, we're optimizing the roof for Solar as much as possible. The home is L shaped, presenting both an east west and north south gables. Was considering changing the North South Gable to a Shed roof. The Gables are going to be 8/12 pitch this puts the panels at a favorable angle for our location. Spokane WA, the shed roof, to be ascetically pleasing, would need to be about 4/12 pitch. Much to flat, especially for winter months in our area for Solar panels. Do you think it would be better to have the flatter roof with twice the panels. Or a steeper roof with half the panels? We are also not allowing plumbers and HVAC folks to put the vents anywhere they want. The roof is to stay clear for Solar ! As we will be on one for one, Net Metering and with the lower cost of Panels these days. I plan to Carpet bomb the house with as many panels as it can hold. We will have all winter to use any extra power, as the Net Metering does not reset till March. Which is early Spring in our location. Would love to hear your deep dive into this and the ins and outs of maintaining Solar panels on steep roofs. 8/12 is not easy to maneuver for cleaning panels but steeper may lend itself to keeping pine needles and leaves off. Look forward to your 2 cents!
Hi Gary, I'd love to help, but unfortunately, I'm not set up, nor insured, to provide consultancy (free or otherwise). Definitely worth getting an installer or two involved to provide you with options and relative benefits of each. Good luck!
@@lindaferguson593 64 panels 250 watt, one three phase inverter 6 kW and three one phase inverters that are 2 kW each. All from China. Next step is to install a battery 10 kW. But I must say that today I would not buy from China. Dictators like Xi and Putin are dangerous and I do try avoiding giving my money to dictators, rather pay more and buy from inside EU or from North America.
A very good video again Gary. I have a SSE facing rear of house (semi detached) and have maxed out roof space. I asked installer about wall mounted panels and front of house NNW facing and they advised against the latter and didn't do the former. As I understand it north-facing panels are not bothered with because they only produce 50% of south facing panels. This ruled them out ten years ago but now that panels are considerably cheaper and more productive should we be taking a look at this option?
Thanks Tony - and yeah, I can't believe how much panel prices have dropped over the last few months. A chance to stick up panels everywhere and anywhere! :-)
I have 1.5kw of older "ex solar farm" panels (6x250w) that I got extremely cheap. Approx 7 years old. Using a 1600w Micro inverter and all panels in parallel on my west facing wall, they produce very little in nov/dec/Jan but will give a lovely boost in late evenings for the 4-7pm octopus flux export slot 😊
Great info Gary, but you are missing one key variable; what I like to call “spousal unpredictably quotient”, which led me to installing an inverter and battery combination that can output 10kW with a 3kW array to deal with the unpredictable nature of our consumption curve.
Timely. I'm in the process of getting a 5Kw inverter with 9kW panels. However the panels are in two locations and one set will be from partially to mostly shaded (there will be optimisers) from maybe 1pm onwards, so that only for a few hours in summer will i get the full 9KW (If ever as maybe I won't get the max before the shading on the "shaded" section starts) Also as I'm in the UK this depends on DNO approval as (as you explain) a G99 has to be applied for. One other benefit of oversizing is that rather than getting a set of panels in one location and then later deciding you'd like more, it's cheaper to install in one go, essentially I'm only really paying for the extra panels as they will be on a garage roof and don't require an extra full set of scaffolding etc and it should be easy (for them) to add these on the same visit. Fingers crossed for me re the G99 it went in yesterday !
please make sure you get g00 permission before the install goes ahead, know of friends who hd similar uk installs last may but yet to get even a msc cert yet alone any permissions.
@@alanclark2584 Amazingly the G99 has been approved, its only been a week I was expecting end this month earliest. Install is now cheduled for second week of Feb. Expect the current sunny weather to end at that point.
Great video, but if you can have a 5kw invertor or a 7kw invertor on a 6.88kw array for the same price, which is the better option. That's the scenario i find myself in and cant quite work out what's best, East array slightly tilted towards south but not by much.
Thanks - if the two inverters are the same price, then you could look at the higher output one as being the better option. Remember though, inverters work best at their higher output, and there will be fewer occasions when it will reach that given your array size.
I would think running an inverter at 100% of capacity would be very hard on it, if for long periods, making it very hot (much like running a car engine at 100% being a bad idea). Am I wrong?
I'm pretty sure inverters are designed for such operating conditions, but I agree, they'll run hotter and that surely has some effect on the lifetime. I'd rather have efficiency though over a slightly extended lifetime though...
@@GaryDoesSolar Many thanks for the reply.....I live where the ambient temperature is ~30 - 35 degrees Celcius during the day, so I was concerned that running the inverter to it's limit might increase the temperature of components to 'cruel levels'. Hopefully as you say, they should be designed to cope with such circumstances.
Thank you for your valuable video. Would you see similar benefits of oversizing array using ENPHASE micro inverters? Perhaps one of your others videos is about that? Regards
You’re most welcome. I made this video last year on micro inverters, which you might like to watch: th-cam.com/video/q6t0AAi5Jws/w-d-xo.html And I hoping to release a video interview with Enphase very soon 👍🏻
Be sure to get battery storage because selling your excess generation of electricity to the grid can really suck if they buy it from you at 5 cents per but sell it back to you at 40 cents per when you need it from them.
Agreed - although I hope more and more energy providers start to pay a better rate for export. If you think about it, your export goes straight to your neighbours - it highly unlikely to get past the sub-station. And that means the grid doesn't have to both supply (and more importantly, transmit) that same power to your neighbours. Everybody wins, in my view :-)
In the uk it’s easy to sell for 15 and buy for 23. With conversion losses and battery outlay this means it’s better to just sell it and buy when you need it.
(Newbie) Doesn't it mainly restrict you to the OCV limitations of your inverter? Is not the smaller the wattage of an inverter have smaller OCV limits?
Each inverter will have a maximum voltage limitation. E.g sungrow 5kw hybrid inverter is 600v so depending on the solar panel voltage this will be the limitation although other factors also come into play such as voc at stc, panel temp coefficient at voc, minimum temp in the area and number of panels in a string.
@@jameshind6644 I guess I should have said VOC instead of OCV though I think they mean the same thing. My puny little inverter/charger I'm starting with has a VOC range of 120-450 but it only has a max PV input of 13A. My panels put out 13.92 ISC (short circuit current) so I am forced to run them in series. I am .92 over so I hope it does not eventually fry the thing. All these different abbreviations are confusing but I think I'll eventually get it.
Hello Gary! Greetings from Brazil! What about if my system uses a power inverter and a charge controller separately. Is there a max VP array power I should use as far as my controler is concerned? The manual for the PowMR 60 pro controller doesnt specify that. It only says the max input power is 1440w on a 24v system. Thank you and have a great week!
Hi Sergio! Thanks for your kind comments. Now, this is quite a specific question about your equipment, and it's best to speak to the company that installed it as there could be other installation aspects which would dictate the answer...
Absolutely agree, oversize your array, but don’t undersize your inverter. Once you have solar you’ll find places to send any excess generation, be it to the grid, batteries, hot water, aircon or car. I doubt that most households would be able to produce more energy than they could consume The great thing about the whole electric ecosystem (at the moment in UK) is the export rate of 15p vs 7.5p import, meaning the right setup could give you zero bills by producing 55% (including losses) of your annual usage
Hi Gary. Thanks for the great info. Can you please list the inverter size of tesla PW3 and PW2? If I am installing 9.72KW of solar array which Powerwall is a better fit? Thank you so much for your time!
You're most welcome, Keerthi. There's a link in the description that takes your to the data sheet, which should provide you with what you're looking for.
Gary, what is your recommendation for people considering adding to their existing array when they are receiving FIT payments? My understanding is that they could potentially lose their payments because their system has been changed from the original and when submitting quarterly generation meter readings they make a declaration that the system has not been changed. Is it to use either a second inverter or micro inverters with the extra panels and connect directly into the distribution panel without going through the generation meter? Thanks
Hi there. This might answer your questions re. the UK feed-in-tariff scheme (which unfortunately has been closed to new applications for some years now). You'll need to join the group in order to access the information: facebook.com/groups/2197329430289466/permalink/6080359505319753/
Thanks Gary, glad you addressed this. I have two systems a SE 6.4kW and an Outback 7.2kW. My grid provider doesn't give its members net metering, they buy all the electricity we produce at wholesale and sell us energy at retail. They also have a max that you can sell them at 15kW. What I've done is put in 17k of PV and even though I only can sell them 13.6kW. On over cast days I make enough to charge my batteries and on sunny days my curve production curve is flatter. Because PV is so cheap now it pays to do this and also enables me to run with a smaller battery bank, which in my case is 15kWh.
My 8 420 w panels have a theatrical max of 3.36kw, i have seen 3.5kw, but on hot days of 30 deg plus i only see 2.6 kw, had i known this i would have squeezed in another 2 panels!
Yeah, i dont have real proove of that too but i keep wonder how much that differs, maybe in days with terrible wetter when a invertor keep switching on and off
Thanks for this informative video. I'm under the impression that a larger inverter can recharge DC batteries from the grid quicker and this is becoming more beneficial as people are installing larger battery banks on their homes. Any thoughts about this aspect?
@@Riceman-o1pfor example. GivEnergy 9.5 can charge and discharge at 80A but the 3.6 and 5kW hybrid inverters can only charge at 65A. In this case, despite what size solar array you have, you may choose to go to a SunSynk hybrid inverter to gain that extra charging speed to suit your time of use strategy. Especially relevant for those who have 2 or 3 batteries in parallel.
@@GaryDoesSolar well it is a small world. I've been box set binging my way through your back catalogue to get myself fully up to speed on solar panels and home batteries. I haven't found anyone as informative and comprehensive about the sector so keep up the great work! 👍
Hi Gary! Nice and very useful video! You earned a subscriber here! Could you please be so kind as to tell me if a system with a 5 kW inverter and 6 kW panels would be OK? Or maybe a 6 kW inverter + 8 kW panels... Honestly, I don't know. All I can tell you for sure is that the energy requirement for my house is approximately plus/minus 6000 kW per year. Thank you very much in advance for your answer.
Hi Andy, thanks for the kind words! Now, I can't offer individual advice unfortunately, but if it were me, I would certainly try to get as many panels on my roof as I could, then get an inverter maybe 20-30% smaller.
Hi Alice - you're most welcome, and thanks for subscribing :-) I checked this website, and it appears that your solar panels can still operate at 85 degrees (although they won't be operating as efficiently): www.theecoexperts.co.uk/solar-panels/too-hot-for-solar-panels
Hello. I have a string of 10 Canadian Solar 455w panels. It was previously connected to a Growatt SPF 5000 ES inverter, perfect operation. Considering that their orientation and inclination are deficient, the maximum power in the 4 months of operation (that I saw) was 4,060w. A few days ago I replaced the inverter with Growatt SPF 6000 ES Plus. It supports, according to the specifications, 8,000w maximum, 4,000 on each string. Considering that the 10 panels comply with the inverter specifications regarding voltage and current (VOC 412V and 13.95A from the 10 inserted panels vs 120-450V and 16A per mppt inverter) do you think they can work at this maximum power of 4,550w or is it too much much per mppt? Some say that yes, this oversizing is good because it is not often reached to the maximum, others say that the maximum power of 4,000w per mppt must be respected. Thank you in advance !
I have a Victron inverter and charge controllers, what I did was lower the percentage on the charge controllers (by software) to keep from getting too close to the maximum input for solar!
@@GaryDoesSolar I’m no expert but it kept it from going over 100 A which was my goal! I took from the peak of the summer, and then figured the rest of the year was a breeze, as it would never get over 100 A. So basically, my charge controllers are set at 85%.
Thanks for the video, i was looking into solar as an option 8kwp with a 6kw inverter and a battery bank, most likely ac coupled to allow for expansion. Though now i have been trying to research microinverters supplying AC straight from the panels - from my understanding this would mean the G99 set as the kwp, with the bonus of no clipping along. Aside from the initial cost would there be any other downfalls? Or has anyone got any real life feedback on microinverters?
I was thinking about, but decided against talking about oversizing in microinverters as well. Essentially, they're the same thing but on a per-panel scale - the same principles in the video apply. The panel might be, say, 400W and the microinverter (e.g. Enphase IQ7+) might be 290W. That's a 133% oversizing.
Hi first time watching your videos and found this very interesting.. I currently have 3kw of panels facing east and a 3kw inverter. When I can afford it I am going to get another 3kw of panels facing west. I also have several 2.4 pylontech batteries that I plan to add before summer. I have a 4kw Solax hybrid inverter and thought I would need to buy a bigger inverter (6kw).. sooo, can I actually use safely my 4kw hybrid inverter with 6kw of panels and several 2.4 pylontech batteries !! Regards Mark
Hi Mark, thanks for watching my videos - and I hope they're useful to you! Check with your manufacturers regarding the maximum oversizing ratio, but it looks like you should be ok. All the best!
I have been approved for 16kw of generation and export by my DNO. I am having two tesla powerwalls installed but am wondering it would be more efficient to have both limited to 8KW or one significantly higher than the other?
* NOTES SINCE RELEASE *
I've been informed that some of the most recent inverters have a very flat efficiency curve that only seems to fall away 5% of the inverter rating. I don't yet have any sources to confirm this, but would welcome if you hear of any.
Shocking value given for free. so well explained. Gary deserves 20X more subscribers.
Ok, you've made my day already (and it's not even 9am in the UK) - thank you! :-)
was watching from Spain, we're 1-2hrs ahead !@@GaryDoesSolar
... and you've given me a target! I'll try my best! 🚀
Gary, you'll never get the views you deserve. Stripping naked on instagram, you might !
I think your YT activities help you to sort your thoughts, and you should leverage your work through consulting, or even designing installations for others.@@GaryDoesSolar
Why is this the first time I hear about the interesting DC and AC battery setup, and of the oversizing of panels? Sounds kinda smart to be honest.
Don't know, but I'm very happy to have brought it to your attention :-)
If you're in the US, it's likely because the Enphase solution is pushed as the best of the best.
I agree. Looking into this and I didn’t realise there was more to this. I feel scared to install solar now in case I make a wrong or less than best decision. I’ve got so many upgrade paths with replacing pool solar and upgrade to battery in future. I feel I could mess this up. Is there good system which exists to cool panels ? Sprinkler or use pool water pump ?
WOW I cant beliive this video has come out today, my system has come online today and my installer recommend a 6KW inverter for my 8.1 kw total panels and 10.5 kW battery system and this video has proved him right.
Fantastic 😀 and good luck with all the solar generation of your system! 👍🏻
Added a 12kwatt microinverter system with no battery. We have met metering and have reduced electric bills to only 10% now. Thanks
We recently installed 31kWp of panels for a house which only had a single phase supply and therefore a limit of 17kW could be connected to the grid, but we were able to use 17kW of SolarEdge inverters and oversize, works really well!
Wow - that's impressive! And it's great to see Artisan Electrics continually demonstrate their immense knowledge and expertise in all the videos you make: th-cam.com/channels/UYJhbsrC1bvVWzgUq83K4A.html
How did you get away with amount of power on single phase? when you are export limited. Here in NZ max export on single phase is only 5kW now. This what has happened in Aussie, too much solar and they have restrictions placed on them now, with lines companies having control and shutting down the PV system using the DRM bulit into the inverters now.
great easy video! another positive thing with oversize array is reaching faster the minimum input voltage of the invertor so that helps getting more solarhours usefull
Thank you :-) I did think about adding in about an oversized array meeting the start-up voltage quicker, but actually I don't think it makes that much of a difference to overall generation. I don't have data to show that though - perhaps someone else has....
There is a misconception about the minimum voltage. The panel voltage is not influenced by solar input, only by temperature. In the morning/evening with little sun input the inverter can have trouble starting up, but that’s solely because of the minimal current needed by the inverter, not because of low voltage.
@@SanneHoekstrathanks for that clarification as I was trying to work out how many panels to have in series/parallel. My preference is to parallel panels rather than use optimisers or micro inverters.
@@jameswestcott4191 I’m not a solar installer, just have some electrical background. I would be very careful with parallel solar panels. In that case you have to add up the maximum amperage, that is a bigger fire risk and you would need way thicker wires. I would stick with a series install. Unless you have much shade, you don’t really need optimizers, all panels have bypass diodes to make sure your install will keep working even with some shade now and then.
In series you need to watch the voc of your mppt
Well done! The only thing I think you missed was that oversizing the array also changes the shape of the curve (same orientation) by allowing more production earlier and later in the day, as well as in cloudy conditions. Basically it will produce more earlier and later, adding to total output or area under the curve...
Cheers! And yeah, the start up voltages are lower for a small inverter. I don't know if it makes too much difference though?
I agree, it's not about voltage but more about current. So for the same "light energy " more current is available from the array. So the larger array will have a different shape curve.
@@caritechsolutions9382 Exactly! All things being equal, at any given time the oversized array will make more power, other than when the inverter is clipping at max output. So if you imagine the std array is putting out say 1000W at a say 8AM, the larger array that's 50% larger will be putting out 1500W. This is cumulatively a pretty significant difference and greatly increases the area under the curve if you were to use your diagrams.
Thank you so much Gary. I have only just discovered your channel with this video. I installed a 5kw array with 5kw inverter a few years ago. My needs have changed dramatically since then. I now have an EV and battery and combined with a pool pump and upcoming heat pump install my system can no longer cope. I’ve been trying to find an inexpensive fix and your video has been a God send. I did not know this was a thing. Oversizing!!!! Wow. I’m a man on a mission now. Many thanks again. I’m now an avid fan and subscriber. So many more of your videos need watching.
Cheers for the kind words 😀 and very happy to have been of help. Hope you find my other videos useful too 👍🏻
I’m planning my own system, and currently working on sizing based on the system input, and panel configuration.
I had come to the same conclusion to over-provision on the PV side, and this video further confirms this industry standard practice.
I’ve been playing around with a single 100W and 400W panel as a proof of concept, and I’ve personally seen examples of everything you’ve described. Thanks!
Great stuff, and thank you 🙏
What you described is probably the solution with the highest possible available financial ROI at the moment. We need to supply power in the morning and evening (see duck curve). We do this by placing panels east-west, not toward the equator. It matters little if your setup harvests relatively less power around noon, because power will often be cheap if not free or negatively priced at that moment anyway.
Oversizing works especially well if panels are cheap and inverters are expensive, which seems to be the case. I heard from a source that I consider reliable that panels HALVED in price over the last year. Prices of inverters seem to have changed very little over the same time period.
NB: It’s important to look at your *actual* expected peak power. 25 panels of 400 Wp each placed east-west probably won’t ever actually produce 10 kW, especially if you’re farther from the equator.
If you have a DC-coupled battery you can get even more power out of your inverter.
Great insight, Frank - thanks for sharing! :-)
THANKS FOR THE WONDERFUL AND SIMPLIFIED EXPRESSION. SO INFORMATIVE AND EDUCATIVE FOR A NON ENGINEER LIKE ME.
Hi Vijay, it is my pleasure - thanks for the great feedback! :-)
Very interesting , good for you .More people will take up solar when they see simplistic explanations of the solar power available . I installed 28x 400w panels at latitude angle with 2x 6000ES + inverters and 3x 9.6kw Li batteries . The result is an abundance of power on a daily basis . The system has been running for 20 months now and I am always looking for more appliances too use up the surplus. 1 inverter had a charging failure which meant that the 2nd inverter had to handle all the charging and loads . It coped well with this , thus qualifying your ( and my ) theory on over panelling . Panels have never been cheaper I encourage those looking into a PV system to add more panels than the energy audit suggests .
Thanks, and great advice for everyone! :-)
Really useful information, thank you! We recently had a 7kW array installed with a 6kW inverter 10kWh SolarEdge battery. I wondered how the battery was able to take 5kW while still exporting 2kW to the grid and this video answered it (the battery is DC coupled). Also watched the video about batteries too. Excellent information really clearly communicated. It's hard to find this level of technical detail without the information being hard to understand.
Wow - that’s great feedback! Thank you 🙏
It was interesting hearing the solar energy requirements in the UK. In the US, most inverters for residential use are sized around 15kw with many being twice that size. A 3kw inverter would be something you would choose for a tiny off-grid cabin. My local utility sets a maximum of 17kw for a grid tied solar system.
Yeah, in the UK the average size of an inverter is 5kW. I like that inverters used in the the US are way bigger :-) Much more useful!
Thanks Gary, I must admit I thought i knew what you were going to say and I got some of it right, but you made many more points than I expected.. Excellent video content and delivery.
Thanks. And great to hear you're already well up on the topic! Hope the video helps a lot of people when deciding what size of array and inverter... :-)
This is a great video. You explain things so well, and the graphics are excellent. Thank you so much.
That's really kind of you to say, thank you! :-)
First time I see one of your videos. Congratulations for such a clear and great video. I subscribed right away!
Thanks very much! Great to hear - and I'll keep the videos coming...
Gary, Thank you for another fine video. Two years ago I increased my system from 12 kW to 15 kW in anticipation of my purchase of an EV. I did this on the recommendation of my excellent solar contractor/electrician. Since my SolarEdge inverter is 10 kW I’ve been wondering if the oversizing contributed to the premature failure of the inverter. You read my mind and put that concern to rest.
Thanks for the great feedback on the video, Richard... and happy to put your mind at rest :-)
It pays to know the product before adding more panels. Usually there is a spec that says maximum amps allowed from the PV and it will be a bit beyond the normal operating range. Don't exceed that rating. Particularly for chargers (standalone or inverter/chargers) the better ones will detect over voltage on the battery side and can take action to force charging current off hard by shorting the PV to handle situations where the charging circuit fails and supplies uncontrolled current to the battery system. Even the ones that have PV relays can have this. Too many amps = damaged 'shorting circuit' and all the possible failure modes that stem from that.
@@retrozmachine1189 This is certainly the value of a good installer 👍
Great video again! I am seriously started thinking I should really replace my 450w panels to 550w.
Wow - 450W is pretty good already, but with solar panel prices falling recently, if you can get the same dimensions, then why ever not? Good luck! 😃
I did this without realising. Managed to get another 3 panels on,y Tony roof in landscape, on top of the rest in portrait. It’s really made a difference. Next looking to get some on the back roof even through it’s north east facing, maybe 4 more, and then add the batteries. While my export rate is great here in Ireland at 29c a unit, it’s dropping more and more. So batteries with extra panels make more sense.
Brilliant!
Nice one Gary, your videos keep just getting better. And now great T-shirts too!
Thanks Chas :-) Yeah, I'm trying to incrementally improve aspects with each video - hard work but worth it! Glad you like the T-shirt - the reason I got one is really so I don't have to spend time choosing what I'm going to wear for a video! Lol
Another super interesting informative video Gary. I oversized my array, 9.6kW on a 7kW inverter and 9.4kW battery split across two roofs. So makes alot of sense to maximise generation from the roof space we have without a bigger inverter
Hi Rob, thanks for your kind words about the video. And great to hear your arrays are working well for you 👍🏻 😀 oversizing is fab!
This is a great video and extremely informative well scripted, videography was great and the information was accurate and well spoken to the targeted audience.
Also it highlights some of the issues I have with solar power being pushed so hard. Firstly I think that solar is a wonderful thing there is no argument there at all, none, however storage is less than optimal and expensive. Then the very folks (read the government) that push the solar alternative charge you exorbitant fees to add solar above some prescribed rating to your home. Then the insult to that injury is that the folks that push the solar (read the government) on you regulate the amount of income you can receive from the power company for excess electricity that you, using the equipment bought, paid for and installed by you, kindly sell back to the grid for your neighbors usage.
If you step back and take a zoomed out view, instead of the myopic view of solar is so great and I am doing something great for the planet, then you can see that something is just not right at all with the "solar plan" the government makes, if it is needed so badly why charge crazy fees for the licensing above a certain size, the licensing for the installation, the taxes on the equipment and taxs and fees for the re-selling back to the grid?
And yes I understand the need for electrical qualified electrical installations that are inspected by those very folks. (read the government) (humor here).
Where I live there are no restrictions for solar you can add as much as your wallet allows, but I used 390 kwh of electricity last month so my 50 dollar electric bill does not make me want to install $10k worth of solar panels, inverter, solar battery managers and batteries to drop the grid.
The perfect solution was fielded by Musk at one time, electrical co-ops, where you and nine other neighbors (10 being an arbitrary number) were the entire 'grid' for yourselves. 10 homes with this oversized solar like in the video, a centralized 10 Powerwall system and 10 inverters, one in each home. No power back the real grid, and everyone shares the benefits and the costs.
Thanks for the kind words, Jim. And also for your insightful thoughts!
UK NW England. Install on SE facing roof.
System: 6.2KWp + 5KW inverter + 13KWh battery. Had to hand £600 to DNO for sign off, but otherwise happy. We generate 6MWh/year.
Good analysis. More winter power when you really need it. In summer too much power to use.
Thanks Nick - and wow, that was quite a price to pay for the G99!! Great generation! :-)
Found this excellent channel today. Going to be 8k inv 12k solar ratio in a month. All my upgrades this month are engineered for winter production, 2x 2790w to 3255w, and a new 3300 array PV2 remains at 2790w. As a whole 8370w to 12600w, the 2790's have peaked at 3514w (vertical bifacial) with this set up I expect the 3300 will max at 4000. Overcast winter estimate 3200 watts total and should give me the 14.6 kw I use daily. I dealt with 105 days of overcast and fog. November 2023, 4 hours direct sun for the month, December was 8hrs and January at 13 hours, 3 months 25 hours of direct sun. My inverter was silent for months. In heavy overcast pv2 a 2790 array produces a minimum of 580 watts. Bi facial panels are mini black holes.
Hi Bob, great that you found my channel :-) And thanks for sharing details about your solar installation and performance!
@@GaryDoesSolar It seems the 2nd inverter was showing inflated pv values on pv1 and 2 it was producing different #'s with the same array switching inputs. My solar dealer drove 8 hours to do a free upgrade to a amen 10kw, same as NHX10, all my data flawed, looks like the 580w from pv2 is actually 380w in heavy rain. So far I cannot get any data using 6kw a day the pv is clipping from sunrise.
@@bobmonztr Ah ok. Good that you now know what was going on, I guess...
Good to see someone 'focus' in on the issues
Haha - thanks - I managed to get my iPhone camera to behave itself this time! :-)
Great video and very well explained. However a roof has a load maximum based on the set up of the roof, the tiles used, then the additional weight of the mounting system, panels and any snow predicted for that area. Whilst it makes sense to do oversize the array if you can, ensure a weight load is carried out on the structure of the building to ensure the roof is capable of taking the extra load.
Totally agree 👍🏻
Interesting video. Had solar for 13 years now great investment. One thing you didn’t mention the other big killer is temperature. Cold sunny day in December can giver way more peak than you would expect where as peak output an a 33 deg day can be disappointing. Last year on the 40 deg days power was way down.
That's a great point to make, John, and I'm not sure many people are aware.
Thank you Gary , your videos have helped me out so much.
You're most welcome. Very happy to have been of some help to you! :-)
😊 This is the 1st video of yours I've seen. Very interesting. I'd like to learn what ever difference there woukd be if not a house. But a flat roof recreational vehicle. In the US, there isn't a rule saying you can't take a solar array to the edges of an rv roof. But, for the most part, they are going to be parallel to the ground. Don't think there is any restrictions on sizing an inverter on an rv either.
Thanks, Edward. Now I don’t know too much about the intricacies of flat roof installations in RVs etc. but I’d imagine there will be people out there on TH-cam with videos on that 👍🏻
@@GaryDoesSolar This vid is the first one I've seen that addressed sizing the solar output vs. the inverter.
Another great video Gary, thanks.
My array is 6.8kWp on a 5kVA (4.4kW) inverter (55% oversized) and tbh I would have installed more PV capacity if I could have fitted it on my roof. It's a DC coupled Victron system with 14.4kWh of Pylontech batteries so I can avoid clipping most of the time. I'm also based in central Scotland and although my roof is facing 184 degrees, the pitch is just 14 degrees so it's unlikely I would see 6.8kW from the array even in summer. So far I've seen 6.3kW max in mid July so I hope to see a bit more than that in late May or early June but I doubt I'll see 6.8kW. In fact my Victron MPPT charge controllers are 250/60 units (2 of them) and although they are spec'd at 3440w each, with my charge voltage of 53.2V, my theoretical max would be something like 6384w total (53.2*60*2).
I am considering adding an AC coupled non-hybrid inverter with four or five 435w panels mounted vertically to my south facing garage wall as a "winter array" to boost my generation. This would be a more cost effective way to add some extra capacity for the winter months than adding another MPPT and having to run DC cabling all the way back to my inverter and battery location. I could just hook it up to the garage consumer unit instead. I might even add a few extra panels to the east and west gables of the garage and use optimisers to allow them to work with a single inverter. A project for later in the year I think. :)
Thanks for sharing this info about your system, Craig - sounds great! And always a good thing to add more panels if you’re able - all the best with it 👍🏻
Thank you very much, Gary. Your videos are the best classes on TH-cam on this subject. I would like to take this opportunity to send a question:
Do you think that adjusting the tilt of the panels, to maximize winter production, could be a good strategy to minimize clipping on an inverter overloaded by 150%? Would this strategy bring more overall efficiency?
I haven't been able to find studies on this strategy yet...
Thanks very much for this great feedback - very much appreciated :-)
Now, are you talking about a ground array (easier to change the tilt twice a year, say) or a roof mount (all sorts of complications including access)?
It is a ground array, but not easy to change the tilt… I will not change It.
Shot in the dark, Have you ever looked into wind and solar as an option? I've just had solar installed to provide energy to our property and I'm just starting to experiment with a small turbine to provide power to my workshop albeit just lighting for now.
Hi Graham, now, wind generation is certainly an option that many are starting to look at, to compliment solar. But (unfortunately) there are a number of factors that limit it’s viability in consumer applications:
- Wind turbines are not quiet - worse, the noise varies with the wind strength, could drive any neighbours close by insane.
- They are also nothing like solar panels in terms of reliability - you might find you’re spending a fair amount of time, money and effort keeping them going.
- And they’re expensive. Like really expensive for one that generates even just a few kW.
- Also watch out for the advertising. Some retailers talk in terms of kW (power) when they’re actually taking about kWh (energy) - even a cheap 30cm diameter turbine will generate 20kWh given enough time!
well said, brother... I'm kinda new at this solar thing, and I had a hunch that getting the max output of power was literally - a moving target. On "paper" it's a static number, but in real-life, there are many variables and most of them are in constant movement. Kinda like going duck hunting with a bee-bee gun and not a shot gun. Greg (garden grove, CA)
Hi Greg - thank you for taking the time to comment, and glad that my videos are useful to you! You're not wrong about trying calculate max power - haha!
Excellent presentation. Clear and succinct. Thank you!!
Cheers Owen for this really great feedback! :-)
Very helpful and detailed in an easy to understand way , many thanks.
Cheers Andrew - that's great feedback to receive! :-)
Learned some new things about solar energy. Thanks!
Great to hear! And you're most welcome! :-)
Thanks for this Gary. I am now going to check if I can fit extra panels as in their current configuration I am maxed out.
My pleasure, and good luck! 😀👍🏻
I've a 6kw Solis inverter and 18 PV 370 watt Panels, is that over sized,had 14 Panels last year,but had the extra ones fitted this month, seams to be a improvement in generation on the odd days we've had a bit of Sun 🌞
That's great to hear, Ian. And hopefully further improvements as the year goes on! All the best :-)
Perfect - we do exactly the same on a DC coupled system mainly for winter shortfall (adjustable array), just be a bit careful as summer yields even inthe the UK, can be 10x what you expect, so stuff can get very hot quickly - we may do a G99 as currently just do off-grid - but even with OE at 15p/Kwh export (upto £1k / pa????), i'm not sure that its worthwhile? - having said all this I'm just configuring my system for VE Dynamic ESS (and G99 approval) for possible use with OE
Sounds great! Thanks for sharing this - will help others!
Another brilliant video from Gary,
Cheers Ian! :-)
Hi Gary, OK I understand. Thanks for your reply. Regards Mark
No problem - hope the link is useful to you
At 6:30m you exactly describe what I want to do. And I have a SOLAREDGE setup with exact that configuration and a DC-battery. Except for : it does-not-work ! The system ignores the charging/decharging time table completely. Even discharges the battery a few percent under the set minimum backup, ánd imports energy from the grid what I blocked in the settings to bring it back to '40%' after discharging to 38%. And it continues to cahrge/discharge throughout the night..
Yeah, I'm hearing solar edge batteries are quite limited in their programming ability, unless you have "installer" type access...
@@GaryDoesSolar My app gives the options for opimised self use/sceduled/backup. I contacted SE and they reply the problem is that I have three inverters.. .. which is nonsense as they are independent systems, one is even in another building in my ground. Batteries directly intalled with hybrid-inverter. Installer comes by next week checking all devices for updates.
I've oversized my system and designed it around winter. I've got 3 x more panels than my charge controllers can process. I've designed it for dark and cloudy days. So high voltage strings in parallel, to get the most from Mppt. I built a ground array facing south.
I live offgrid in Sweden. I've got my panels aimed for the winter sun. Also, the steep angle helps keep snow off, but after every snow fall I still need to go out and scrape off snow. That saying, in the sommer my batteries are usually full by the time I get up in the morning. I'm not worried about the bad solar panel sommer angle as I have such long daylight hours. Also in sommer I turn off most of my strings.
I run 12V for everything, but have a 3kW inverter I can put on when I need, mostly for the washing machine, (always run with only cold water and 40min cycle)
It works for me.
Sounds like a workable solution 👍🏻
Hello. Did you say you have 3x the amount of panels for your charger? I thought each string has a max amount of input from panels coming in and to not go over that amount or it will compromise the inverters performance? What do you say on this Gary? Also, greenbymoon, what brand and size inverters do you have with how many panels in what wattage? Thank you.
@@lindaferguson593 I don't have a permanent inverter running, as I'm using a full 12V system for everything in my offgrid house, which is about 40m².
I have a Giandel 4000w 12V Pure Sine Wave Inverter I use to run my washing machine for 28 min about every 10 days when I have sunlight.
I have 18, 335W solar panels set up in 3 parallel and 5 strings, each string on its own DC circuit breaker.
I have all turned on during what I call the dark season here in Sweden, Oct to end Dec. Then the snow falls and albedo effect starts making a big difference.
I start turning off strings as my light level increases, in Sommer I run just 1 string and my battery is full when I wake.
I get sunlight in sommer from 0300 to 2300. Winter 0900 to 1430
@@greenbimoon wow!!! Amazing!!!
@greenbimoon what is 40m 2? In square feet? Also, do you heat with wood? Thank you.
Agree with all the point you make Gary, except for the one about dirty panels reducing power output.
My own personal experience, I’ve had a 4kW FIT array since 2016. Every year annual generation has been around 3mW, some years more, some years less. I’ve seen no obvious degradation due to dirty panels (or panel ageing); the panels had never been cleaned until last January when we had scaffolding up to install our new 10kW array. There was a bit of lichen in a couple of spots but the panels were pretty clean considering. I’ve read that they do generally keep themselves clean with rain and wind, and that’s been my experience.
Of course if you’re heavily overshadowed by trees or birds dropping on the panels then yes a potential issue, but then you’ve got other shading problems as well
Dirty panels is not a problem in the wet and windy UK, here in southern Spain we have a lot of dust, and rarely sand laden rain from north Afrika and very little rain at other times
That’s great, Geoffrey - and I’m noticing the same with my panels. I thought I’d have to clean them regularly (bird mess etc.) but with the regular rain, the panels self-clean 😀 Countries with less rain might have a dust issue over time though…
Yes fair comment about dusty and less rainy countries. I was thinking from personal wet UK experience.
But to caveat the "no issue with dirty panels message", when we had the extra panels fitted last year, as they filled in the gaps on the rear roof, one new panel was underneath the TV aerial and within a couple of weeks the panel was covered in bird poo. Had to go up on the roof, fit bird spikes and wash the panel
mW is not a unit of energy. It is a unit of power. So 3,000 kWh per year would be a proper way to express that.
@@Riceman-o1p there seems to be plenty of websites explaining what a megawatt hour is. I should have written it as 3MWh though (capital M). I wrote it that way because it makes me feel like a big electricity generator 🤣
3000kWh is just as good
Hi Gary, Thanks, that's very informative. Re the inverter efficiency @5:00, are there figures for this? Also, AIUI inverters with different AC output ratings may have the same internal DC capability. I'm thinking of the GivEnergy Hybrids where 3.6 and 5kW inverters both have the same 7.5KW DC capability, so they can simultaneously export 3.6kW AC and charge a DC battery. Presumably the efficiency of these would be identical?
You're very welcome. I don't have efficiency figures myself (just statements from inverter manufacturers that I've read). Your final question is a good one to ask on a GivEnergy forum...
I thought that was very helpful though it is less easy to see how running two arrays pointed differently would impact on your overall generation and the extent to which you can over-provide capacity against the inverter limit.
Hi Rhian, I developed a utility that you can carry out some modelling on. It's not free, but I've kept the costs quite low:
www.garydoessolar.com/solarazma_pro_intro/
Hi Gary, you have brilliant videos and it's nice to get it from a UK very knowlegable source as opposed to the reams of mainly American DIY vids. I was just wondering, if you are not trying to reduce bills by feeding back to the grid , is it possible in the Uk to have a connection to your house by a change over switch set up a bit like a generator plug in point where you can either feed your house from the grid OR feed your house from your solar inverter in a way that it would be impossible to send solar generated power into the grid. ie, one or the other without the hassle of G98 / G99 acreditation.
Thanks for your kind words re my videos - that's such great feedback! :-)
To your question, unfortunately, not. Any changes to a residential property's electrical system wrt renewables must be G98/G99 certified.
Very informative Gary. Your the MAN 🎉‼️
Thanks - that made my day! :-)
Thanks thinking about making the jump your videos are very informative, can I ask what does this mean for a enphase your system with microinveterrs and AC system + battery
You're most welcome - thank you for the kind words :-)
See my comment to @andyb8268 next to yours. Enphase wants me to interview them for a video shortly, so I'll try to cover this with a question...
Hi Gary,thanks great video.Can you maybe enlighten me,what is the solar maximum size on a 5kw inverter,as i understand the voltage is the biggest issue.Will apreciatre your input.Im from South Africa
So, this is a question you'll need to ask the inverter manufacturer or your installer, as they're all different.
Thanks for the kind words about the video :-)
Hi Gary thanks for the reply,i actually want to know,i have a deye 5kw and it states that the max pv is 6500w,17amp.What i wanna know does it matter if i use 550w panel,that panels state that it has a cs amps of 13.Will this be fine for the inverter?
@@johanerasmus6721 Thanks for supplying the extra detail. This is definitely a question for your installer, I'm afraid. It's not one I can answer, sorry :-(
Thx a lot nice videos lots of learning however can you highlight can we consider inveters which allows overloading upto 50% and post same can we say oversizing concern is resolved thx.
Thanks for the kind words about the channel. I'd love to do all these things and more, but I'm just one guy currently with a fairly intense day job, so it's very difficult to find the time... I'd love to do solar stuff full time one day though... let's see what happens... :-)
5:50 east west is nice as most inverters are dual mppt input so each side,note there is now g99 fast track if under 7.6kw ish (32amps) usually approval time is much shorter (The general issue is a lot of solar installers won’t do it because they just wanna make quick money)
Thanks. I’ll check out the G99 fast track (under 7.6kW) - I wasn’t aware….
@@GaryDoesSolar as long as its not more then 32A (7.6kw clipped inverter I think) it's usually less then 30 days (unfortunately some DNOs are not as nice to work with for g99 and force a 16A g100 device so you need battery storage system to get the most out of your install)
might be more hops if it's past 32A total install and max total generation is 60A per phase if you have Mutiple inverters (usually require a g100 limiting device so generation power can be cut off when DNO requires it)
If you look for g99 fast track + your area DNO there are quite a number of sites
when looking for installers including g99 in search should filter it down to a smaller amount installers who are willing to work with DNO to submit the correct paper work
Greetings. Congrats for the video. I didn't know the benefits of oversizing. I was amazed. I have a growatt spf 6000 es plus. Now I have 12 sunket stk410M10 panels in series for
One MPPT. If I don't bother you, can you tell me how many panels I can install at most? I'm sorry for the bad English. Google. Translator
Greetings from Italy
Thank you - you're most welcome! Unfortunately, I'm not set up to provide individual advice, but it's worth you reaching out to an installer and getting their view on what you'd like to do...
In my country you only get the government grant if you export less than 20% of the energy produced. Over-sizing can get you in trouble. Since I stop working from home and bought more efficient appliances I'm finding harder to consume all that electricity, by this summer I guess I'll have the car plug in everyday to use that 80%
Hi Samu, which country is that? I guess they don't want to much export then! And yeah, it puts a lot of pressure on you to try and consume all that energy!
Great video Gary. I'm thinking about starting small using micro-inverters. Can you comment how "oversizing" affects this scenario please?
Thanks 🙏 Worth watching the section on clipping in this video I made on microinverters:
th-cam.com/video/q6t0AAi5Jws/w-d-xo.htmlsi=S0KhOowQub3gTWd4
Absolutely correct, even with microinverters. The peak is clipped but area under the curve is still larger.
The objection of course is the higher initial cost but ROI could be quicker.
True
The lower limit on UK setups without jumping through a load of hoops is crazy. Almost like they don't want people to make the most of the products available.
Is it allowable to have one 'on grid' and one 'off grid' setup that don't overlap at all?
Good question - but one I don't have an answer for Perhaps others might?
Very informative. Thank you for your video!
You're most welcome - thank you! :-)
We have 6.4kWp panels feeding a 5kW Solar Edge inverter with Tesla Powerwall 2. The inverter frequently clips during summer, and every time I look at that flat-topped curve I can't help but wish we had gone for a 6kW inverter. It would have cost little more and given us more energy.
Worth using the solar modelling utility mentioned in the video to see what you would have gained. Maybe not as much as you might think?
100% Brilliant Video
1. Take your Roof Size and work out what is best for your size of roof, dont just go for the biggest wattage panels as the physical panel size might mean installing a lower watt panel would mean more panels i.e. 10x450w panels is 15sq m but having 15x400w panels is also 15sq m but the lower wattage panels would actually give you a higher peak. which is higher early morning and higher late afternoon.
2. Solar clipping is never expanded on enough in my opinion especially in a country like the UK which is rare to have peak production so having more panels/larger array means more kw production.
3. I even prefer micro invertors so even when clouds partially cover some panels the other panels are still producing maximum
4. Oversizing also allows for panel degradation. A panel typically loses 1% in the 1st year and lets say 0.5% each year there after, over sizing means in 20 years your system is still performing like the 1st day you installed it.
5. Oversizing - Also possible you can also "clip" your export too (Export Limiter), so if you have batteries/or not and are producing 6kw you can charge all this 6kw to your batteries when they are full you will then only export at 3.68Kw; again the full 3.68kw for longer due to the clipping. Or your producing 6kw using 3kw in your house and exporting 3kw (saving and making you money).
The cost of panels is now relatively cheap, by this i mean if your installing 10 adding a few more is not a huge cost.
This is one of the best videos i have seen that explains Oversizing/clipping. When i designed my own solar array i even found a white paper from "Enphase" showing the advantages of doing this but it was pages and pages of numbers and graphs; being a geek i took to it, but thought how can "Joe Bloggs" be expected to understand this stuff. They just want to know what does it cost and when will it pay for itself/make me money. Also the downside for a Solar company that would quote a larger oversized system would be more expensive than someone who didn't so i feel for them too.
Thanks Simon-that’s fantastic feedback to receive 😀🙏
This is a GREAT information! Thanks for posting. 😃
You're most welcome, Tom - great to hear it was useful to you! Cheers, Gary :-)
Thanks for your video Gary; very informative. Pardon me but I am a total noob who has just had his first Sunsynk 8kw installed at his home. I heard the installers speak about the voltage limit on the inbuilt dual MPPTs as something that will limit the size of our array to around 8,4kw. The MPPT are apparently limited to 450v and the array cannot exceed that per string. Can you be kind enough to comment on that?
You're most welcome. Now, I don't have any experience of SunSynk equipment, but it's worth signing up to this Facebook group, where you could ask those kinds of questions. Lots of support there... good luck! facebook.com/groups/571819024654208
@GaryDoesSolar Thanks for your prompt and kind response.
Food for thought.
Cheers - glad the video was useful!
Hi Gary, I'm a Gary too. We're building a house shortly. Unfortunately being on a lake, view is determining position of the home over Solar. That said, we're optimizing the roof for Solar as much as possible. The home is L shaped, presenting both an east west and north south gables. Was considering changing the North South Gable to a Shed roof. The Gables are going to be 8/12 pitch this puts the panels at a favorable angle for our location. Spokane WA, the shed roof, to be ascetically pleasing, would need to be about 4/12 pitch. Much to flat, especially for winter months in our area for Solar panels.
Do you think it would be better to have the flatter roof with twice the panels. Or a steeper roof with half the panels? We are also not allowing plumbers and HVAC folks to put the vents anywhere they want. The roof is to stay clear for Solar ! As we will be on one for one, Net Metering and with the lower cost of Panels these days. I plan to Carpet bomb the house with as many panels as it can hold. We will have all winter to use any extra power, as the Net Metering does not reset till March. Which is early Spring in our location.
Would love to hear your deep dive into this and the ins and outs of maintaining Solar panels on steep roofs. 8/12 is not easy to maneuver for cleaning panels but steeper may lend itself to keeping pine needles and leaves off. Look forward to your 2 cents!
Hi Gary, I'd love to help, but unfortunately, I'm not set up, nor insured, to provide consultancy (free or otherwise). Definitely worth getting an installer or two involved to provide you with options and relative benefits of each. Good luck!
@@GaryDoesSolar was not asking for professional assistance. I already have the answers. It was more a topic suggestion for you.
@@Useitorloseit1 Ah, ok - got it - thank you 👍
Agree this is also my experience from my oversized system since 10 years. No problems so far but we live in a cold climate Sweden .
That's really great to hear, Peter - thanks for sharing. I love Sweden :-)
What system components do you have?
@@lindaferguson593 64 panels 250 watt, one three phase inverter 6 kW and three one phase inverters that are 2 kW each. All from China. Next step is to install a battery 10 kW. But I must say that today I would not buy from China. Dictators like Xi and Putin are dangerous and I do try avoiding giving my money to dictators, rather pay more and buy from inside EU or from North America.
@@peteroffpist1621 thank you.
@peteroffpist1621 do you have batteries already installed with your existing components for night time use?
Thank you for the video
You're most welcome 👍🏻
A very good video again Gary. I have a SSE facing rear of house (semi detached) and have maxed out roof space. I asked installer about wall mounted panels and front of house NNW facing and they advised against the latter and didn't do the former. As I understand it north-facing panels are not bothered with because they only produce 50% of south facing panels. This ruled them out ten years ago but now that panels are considerably cheaper and more productive should we be taking a look at this option?
Thanks Tony - and yeah, I can't believe how much panel prices have dropped over the last few months. A chance to stick up panels everywhere and anywhere! :-)
I have 1.5kw of older "ex solar farm" panels (6x250w) that I got extremely cheap. Approx 7 years old.
Using a 1600w
Micro inverter and all panels in parallel on my west facing wall, they produce very little in nov/dec/Jan but will give a lovely boost in late evenings for the 4-7pm octopus flux export slot 😊
Great info Gary, but you are missing one key variable; what I like to call “spousal unpredictably quotient”, which led me to installing an inverter and battery combination that can output 10kW with a 3kW array to deal with the unpredictable nature of our consumption curve.
My wife says she'll use what she wants, when she wants, and I have to work around that... I may need a larger inverter after all then! ;-)
Timely. I'm in the process of getting a 5Kw inverter with 9kW panels. However the panels are in two locations and one set will be from partially to mostly shaded (there will be optimisers) from maybe 1pm onwards, so that only for a few hours in summer will i get the full 9KW (If ever as maybe I won't get the max before the shading on the "shaded" section starts) Also as I'm in the UK this depends on DNO approval as (as you explain) a G99 has to be applied for.
One other benefit of oversizing is that rather than getting a set of panels in one location and then later deciding you'd like more, it's cheaper to install in one go, essentially I'm only really paying for the extra panels as they will be on a garage roof and don't require an extra full set of scaffolding etc and it should be easy (for them) to add these on the same visit.
Fingers crossed for me re the G99 it went in yesterday !
please make sure you get g00 permission before the install goes ahead, know of friends who hd similar uk installs last may but yet to get even a msc cert yet alone any permissions.
opps G99 permission
@@alanclark2584 thanks. Yes the supplier won't go ahead without G99 it's all on hold until then
Hope all goes well with the installation (and of course, the response from your DNO)! :-)
@@alanclark2584 Amazingly the G99 has been approved, its only been a week I was expecting end this month earliest. Install is now cheduled for second week of Feb. Expect the current sunny weather to end at that point.
Great video, but if you can have a 5kw invertor or a 7kw invertor on a 6.88kw array for the same price, which is the better option. That's the scenario i find myself in and cant quite work out what's best, East array slightly tilted towards south but not by much.
Thanks - if the two inverters are the same price, then you could look at the higher output one as being the better option. Remember though, inverters work best at their higher output, and there will be fewer occasions when it will reach that given your array size.
I would think running an inverter at 100% of capacity would be very hard on it, if for long periods, making it very hot (much like running a car engine at 100% being a bad idea).
Am I wrong?
I'm pretty sure inverters are designed for such operating conditions, but I agree, they'll run hotter and that surely has some effect on the lifetime. I'd rather have efficiency though over a slightly extended lifetime though...
@@GaryDoesSolar Many thanks for the reply.....I live where the ambient temperature is ~30 - 35 degrees Celcius during the day, so I was concerned that running the inverter to it's limit might increase the temperature of components to 'cruel levels'.
Hopefully as you say, they should be designed to cope with such circumstances.
Thank you for your valuable video. Would you see similar benefits of oversizing array using ENPHASE micro inverters? Perhaps one of your others videos is about that?
Regards
You’re most welcome. I made this video last year on micro inverters, which you might like to watch: th-cam.com/video/q6t0AAi5Jws/w-d-xo.html
And I hoping to release a video interview with Enphase very soon 👍🏻
Thank you very much for quick respond. I look forward to enphase video.@@GaryDoesSolar
I added panels to my house to get east & west generation but used a micro inverter on each panel.
Yes, microinverters are great examples or array oversizing on a per-panel basis ❤️
Be sure to get battery storage because selling your excess generation of electricity to the grid can really suck if they buy it from you at 5 cents per but sell it back to you at 40 cents per when you need it from them.
Agreed - although I hope more and more energy providers start to pay a better rate for export. If you think about it, your export goes straight to your neighbours - it highly unlikely to get past the sub-station. And that means the grid doesn't have to both supply (and more importantly, transmit) that same power to your neighbours. Everybody wins, in my view :-)
In the uk it’s easy to sell for 15 and buy for 23. With conversion losses and battery outlay this means it’s better to just sell it and buy when you need it.
(Newbie) Doesn't it mainly restrict you to the OCV limitations of your inverter? Is not the smaller the wattage of an inverter have smaller OCV limits?
Oh crikey - I don't actually know the answer to that. Maybe someone else does...? I may have to do some further research...
Each inverter will have a maximum voltage limitation. E.g sungrow 5kw hybrid inverter is 600v so depending on the solar panel voltage this will be the limitation although other factors also come into play such as voc at stc, panel temp coefficient at voc, minimum temp in the area and number of panels in a string.
@@jameshind6644 I guess I should have said VOC instead of OCV though I think they mean the same thing. My puny little inverter/charger I'm starting with has a VOC range of 120-450 but it only has a max PV input of 13A. My panels put out 13.92 ISC (short circuit current) so I am forced to run them in series. I am .92 over so I hope it does not eventually fry the thing. All these different abbreviations are confusing but I think I'll eventually get it.
Fantastic explanation 👏👏👏👏👏
I'm humbled - thanks for this great feedback, Jacques :-)
Hello Gary! Greetings from Brazil! What about if my system uses a power inverter and a charge controller separately. Is there a max VP array power I should use as far as my controler is concerned? The manual for the PowMR 60 pro controller doesnt specify that. It only says the max input power is 1440w on a 24v system. Thank you and have a great week!
Hi Sergio! Thanks for your kind comments. Now, this is quite a specific question about your equipment, and it's best to speak to the company that installed it as there could be other installation aspects which would dictate the answer...
Absolutely agree, oversize your array, but don’t undersize your inverter. Once you have solar you’ll find places to send any excess generation, be it to the grid, batteries, hot water, aircon or car. I doubt that most households would be able to produce more energy than they could consume
The great thing about the whole electric ecosystem (at the moment in UK) is the export rate of 15p vs 7.5p import, meaning the right setup could give you zero bills by producing 55% (including losses) of your annual usage
Brilliant! :-)
Hi Gary. Thanks for the great info.
Can you please list the inverter size of tesla PW3 and PW2? If I am installing 9.72KW of solar array which Powerwall is a better fit? Thank you so much for your time!
You're most welcome, Keerthi. There's a link in the description that takes your to the data sheet, which should provide you with what you're looking for.
Very informative, thank you.
Cheers for taking the time to let me know - I'll keep the videos coming... :-)
Gary, what is your recommendation for people considering adding to their existing array when they are receiving FIT payments? My understanding is that they could potentially lose their payments because their system has been changed from the original and when submitting quarterly generation meter readings they make a declaration that the system has not been changed. Is it to use either a second inverter or micro inverters with the extra panels and connect directly into the distribution panel without going through the generation meter? Thanks
Hi there. This might answer your questions re. the UK feed-in-tariff scheme (which unfortunately has been closed to new applications for some years now). You'll need to join the group in order to access the information: facebook.com/groups/2197329430289466/permalink/6080359505319753/
Thanks Gary, glad you addressed this.
I have two systems a SE 6.4kW and an Outback 7.2kW. My grid provider doesn't give its members net metering, they buy all the electricity we produce at wholesale and sell us energy at retail. They also have a max that you can sell them at 15kW. What I've done is put in 17k of PV and even though I only can sell them 13.6kW.
On over cast days I make enough to charge my batteries and on sunny days my curve production curve is flatter. Because PV is so cheap now it pays to do this and also enables me to run with a smaller battery bank, which in my case is 15kWh.
That's just brilliant - I love the way how you've essentially maximised matters around the constraints :-)
My 8 420 w panels have a theatrical max of 3.36kw, i have seen 3.5kw, but on hot days of 30 deg plus i only see 2.6 kw, had i known this i would have squeezed in another 2 panels!
Yeah, you can never have enough panels!!! :-) :-)
Yeah, i dont have real proove of that too but i keep wonder how much that differs, maybe in days with terrible wetter when a invertor keep switching on and off
If I find out anything, I'll let you know... :-)
Thanks for this informative video.
I'm under the impression that a larger inverter can recharge DC batteries from the grid quicker and this is becoming more beneficial as people are installing larger battery banks on their homes.
Any thoughts about this aspect?
All batteries have a maximum charge rate so just make sure that you pay attention to that as the limiting factor.
@@Riceman-o1pfor example. GivEnergy 9.5 can charge and discharge at 80A but the 3.6 and 5kW hybrid inverters can only charge at 65A.
In this case, despite what size solar array you have, you may choose to go to a SunSynk hybrid inverter to gain that extra charging speed to suit your time of use strategy.
Especially relevant for those who have 2 or 3 batteries in parallel.
You're most welcome, and as it happens, I've been watching and recommending your heat pump installation videos :-)
@@GaryDoesSolar well it is a small world. I've been box set binging my way through your back catalogue to get myself fully up to speed on solar panels and home batteries.
I haven't found anyone as informative and comprehensive about the sector so keep up the great work! 👍
@@UpsideDownFork Thank you - that's really kind of you to say 😊 I'll keep the videos coming...
Hi Gary! Nice and very useful video! You earned a subscriber here! Could you please be so kind as to tell me if a system with a 5 kW inverter and 6 kW panels would be OK? Or maybe a 6 kW inverter + 8 kW panels... Honestly, I don't know. All I can tell you for sure is that the energy requirement for my house is approximately plus/minus 6000 kW per year. Thank you very much in advance for your answer.
Hi Andy, thanks for the kind words! Now, I can't offer individual advice unfortunately, but if it were me, I would certainly try to get as many panels on my roof as I could, then get an inverter maybe 20-30% smaller.
Very good video, thank you
Cheers! :-) It seems to be quite a popular one too! I'm very happy
thanks this was well explained !
That’s really great feedback - thank you 🙏
Thanks for the info, I just subscribed. Where we are in July and August we can get up to 50 Celsius. Does this damage the panels in any way?
Hi Alice - you're most welcome, and thanks for subscribing :-)
I checked this website, and it appears that your solar panels can still operate at 85 degrees (although they won't be operating as efficiently):
www.theecoexperts.co.uk/solar-panels/too-hot-for-solar-panels
@@GaryDoesSolar many thanks Gary for checking this out for me.
Hello. I have a string of 10 Canadian Solar 455w panels. It was previously connected to a Growatt SPF 5000 ES inverter, perfect operation. Considering that their orientation and inclination are deficient, the maximum power in the 4 months of operation (that I saw) was 4,060w. A few days ago I replaced the inverter with Growatt SPF 6000 ES Plus. It supports, according to the specifications, 8,000w maximum, 4,000 on each string. Considering that the 10 panels comply with the inverter specifications regarding voltage and current (VOC 412V and 13.95A from the 10 inserted panels vs 120-450V and 16A per mppt inverter) do you think they can work at this maximum power of 4,550w or is it too much much per mppt? Some say that yes, this oversizing is good because it is not often reached to the maximum, others say that the maximum power of 4,000w per mppt must be respected. Thank you in advance !
Excellent video.
You're most welcome - thanks for taking the time to watch it :-)
Fantastic video!
Thank you - glad it was useful! :-)
I have a Victron inverter and charge controllers, what I did was lower the percentage on the charge controllers (by software) to keep from getting too close to the maximum input for solar!
I didn't know that was possible. Did it help?
@@GaryDoesSolar
I’m no expert but it kept it from going over 100 A which was my goal! I took from the peak of the summer, and then figured the rest of the year was a breeze, as it would never get over 100 A. So basically, my charge controllers are set at 85%.
Well done!
Cheers 😀👍🏻
Thanks for the video, i was looking into solar as an option 8kwp with a 6kw inverter and a battery bank, most likely ac coupled to allow for expansion. Though now i have been trying to research microinverters supplying AC straight from the panels - from my understanding this would mean the G99 set as the kwp, with the bonus of no clipping along. Aside from the initial cost would there be any other downfalls? Or has anyone got any real life feedback on microinverters?
Thinki just posted a similar question
@@harvyd1967 well hopefully that’s a sign it’s a good idea!
I was thinking about, but decided against talking about oversizing in microinverters as well. Essentially, they're the same thing but on a per-panel scale - the same principles in the video apply. The panel might be, say, 400W and the microinverter (e.g. Enphase IQ7+) might be 290W. That's a 133% oversizing.
@@GaryDoesSolar that’s a good point and item to look, so the clipping essentially occurs at the panel itself.
Hi first time watching your videos and found this very interesting.. I currently have 3kw of panels facing east and a 3kw inverter. When I can afford it I am going to get another 3kw of panels facing west. I also have several 2.4 pylontech batteries that I plan to add before summer. I have a 4kw Solax hybrid inverter and thought I would need to buy a bigger inverter (6kw).. sooo, can I actually use safely my 4kw hybrid inverter with 6kw of panels and several 2.4 pylontech batteries !! Regards Mark
Hi Mark, thanks for watching my videos - and I hope they're useful to you! Check with your manufacturers regarding the maximum oversizing ratio, but it looks like you should be ok. All the best!
Hi Gary, many thanks for your reply.. all the best
I have been approved for 16kw of generation and export by my DNO. I am having two tesla powerwalls installed but am wondering it would be more efficient to have both limited to 8KW or one significantly higher than the other?
Wow-that’s great to hear!
Would your analysis still hold in Phoenix, Az where our temps in the 115s F during summer? Would hate to burn out my inverter.
Yes, solar panels and inverters are designed to operate in very hot and very cold temperatures.
The array on the house in your thumbnail looks perfect - what's the problem? :)
Only that the neighbours are complaining… ;-)