Micro and String Inverters in the Shade - Testing the True Impact of Shade on Solar Panels
HTML-код
- Опубликовано: 21 авг 2024
- NRG Solar's Eddy May conducts 3 months of testing with both Enphase Microinverters and a Fronius String inverter in order to find out the true impact of shade, obstructions and micro-cracks on solar panel production.
People forget that almost all panels have 3 bypass diodes, which will help with shade and micro cracks. That's what's assisting with shade mitigation. I also note the cricket bat induced micro crack was made in a corner of the panel Let's take a look at the same in the centre of the panel.
And 1/2 cut 1/3 cut
a 15 cent diode puts in the work
I was told the same thing about a shaded panel affecting the whole string just yesterday by an installation company. I thought at the time that it sounded ridiculous, because why would anyone put up with solar if that was the case? Those massive strings you see in farmers' fields would come unstuck with the slightest bit of mud on them. I'm glad my hunch was right and you've done the experiments to prove it. I don't have to shell out for the micro-inverters now which should save a significant amount on the installation, and reduce points of failure in the panels themselves. Thanks!
Dear Mr. May. Thank you very much for a brilliant explanation and demonstration of the differences between microinverters and string inverters.
@anthonyramirez6532 I am not an electrical engineer but from what I have read I like the idea of Enphase because they are safer for the installers and because, as far as I can judge, they offer more flexibility with panel replacement. Having said that, I know of old string systems that are performing well after many years.
Thanks for recording and publishing your results. It calls into question the Marketing claims of many Solar Manufacturers.
Well Done Eddy, thanks for spending the time to do this research, interesting results. You deserve a nice bottle of Merlot for this effort
Can I borrow your sippy cup :)
As a previous enphase installer, I must say, I was convinced by the marketing as well, great tests 🙌
You hit this outta of the park. Well done. Changed my mind on this issue. It remind us once again, always take a pint of salt with any marketer's claims.
Thanks Eddy, this is absolutely gold for me at the moment!
am Austrian and was in favor of those micro inverters, now am reconsidering Fronius for two homes, thanks pal :-)
Well done and I really like the fact that you actually built a test system to verify the claims.
Thanks. It’s a pleasure to see someone to clear, thorough and accurate testing!
Great stuff that really squashes some of the hype regarding Enphase. It's certainly not the end all be all when it comes to shade efficiency.
Thank you for a clear explanation of the different responses to shade. Busting a few myths
Great video. Having sold over 1,000 string inverter systems, I always suspected your conclusions to be the case but you really nailed it! Thank you for your efforts.
Ground breaking video because it was done under such tight well thought out controls, so no one can question the Data. I am really looking forward to the parallel panel test and also please do a test on Clipping. I don't believe for a second that clipping averages out over the day. My batteries and Grid Tie will suck every Watt they can get, so peak time with strings means a lot more juice for the batteries.
Lol this is RUclips. People wil *always* question the data :P
As a solar noob who built their own system and decided to do an un popular parallel arrangement I can confirm one thing from this video, what every you choose you can't loose unless you pay to much. I bought my 2kw solar/4000w inverter/8kw of LifePo etc. for $7000au and while the worst 2/3 months of winter is a bit of a struggle I could not be happier otherwise because it provides all the comforts with few compromises. I doubt I am ever going back to being extorted 43c pkwh for something that can be had for fossil free!...Quite the opposite, I will likely buy another 2kw of panels to make that 3 months easier and have as much power as I can use for the rest of the time.
What's your preferences on panels
@@JoJoRocks5 Mine were Jinko cheetah's considered tier 1 but there are many affordable options. They are so cheap that I would just get tier 1.
Thx for info
That was a real blessing to me.
Great work Eddy.
Would be very interesting a similar comparison between Microinverters and DC optimisers
ruclips.net/video/Dme8FGBlelw/видео.html&ab_channel=SolarSurfers
I saw a RUclipsr who showed the effect of a TV mast that cast a long shadow across more than on panel. This really impacted the output but in the end he was not certain if the inverter was not getting fouled up. You may want to have a discussion of various string inverters to see what impact they can have based on some various shading situations.
One of the best explanations of a solar panels. Thank you for that.
Thanks, a really useful series of tests. One thing that could potentially affect the outcome is the panels used - some may be better than others when it comes to bypassing shaded cells. Poorly bypassing panels would show a greater difference between the two. I imagine the marketing departments would much prefer to use those kind of figures, even if if cheap panels and expensive inverters are an unlikely combination! NB I have no evidence as to whether there is any significant difference between panels when it comes to bypassing low output cells, this is pure conjecture.
Very nice and sober test with facts in focus. I have done about the same testing (minus the cricket bat test) on a 4 panel setup and I get the same results. Cover a cell and that, and only that panel is reduced by 33%. If you have a half-cut panel the result will even be half of that. So much marketing and misunderstandings that end up being truth on the internet as it is repeated a million times.
What happened to the parallel testing? Did that ever happen?
Give this man a medal please
Thank you very much. I was always regretting my decision to use string inverter as I later found that there is some shading from neighbour's tree in the evening. I suspected that I was losing 20% of the energy generated as I expected to lose most of the energy after 3:30PM. Now I cam be at peace
Love to see this test including SolarEdge, on summer-ish day when Micro’s limit peak output
Thank you, your tests enlighted me, I am convinced now that a number of marketing issues are non-issues.
"I found the leaves and cut them to scale" LOL. Nice testing!
Great test. Can you do a comparison test between budget panel and premium panel, it would be great!
Top job NRG! Love your work! 👌
2 years later and there doesn't seem to be the follow up video, shame. I really wanted to see that. I keep swinging back and forth between 2 string inverter/2 string with some optimizers and full microinverters. Thanks to this and the video that led me here, I can now see through the marketing BS but as I will have panels on an East and South facing roof, I still need to decide which option will produce the most power whilst taking into account the cost for each solution. I've only just started learning about this stuff so with another few hours of surfing I might start leaning in one direction but for now, I'm standing here scratching my chin unsure which way to go. The East facing side (6 panels) only gets sun early in the morning when the south facing side (18 panels) is shaded. After 10am they both get sun but by 4pm the East side is shaded again. My biggest concern is that one side could pull the other down when it's shaded and this would happen at each end of the day. I've been quoted for a 2 string inverter without any optimizers but he's now suggested adding these for the 6 panels on the East side but then the inverter comes into play. It's currently quoted as 8kwh but with both sides shaded a lot, will the inverter be able to produce anything outside of the 6 hour window? Probably the wrong place to post this, should probably find a forum but seeing as I'm here, any advice?
This is great. I am looking at installing a 50kw ground mount and am trying to decide between string and micro inverters. The information seems to suggest micro are vastly superior, but your experiment seems to indicate that is an over simplification. The difference in performance seems minor in real world conditions but the cost is significantly different. Although you didn't touch on it, the micro inverters don't seem to be a good solution for higher output panels 450+, which appears to be another downside for my particular situation. Thanks for taking the time and expense to do this, very helpful.
Interesting and useful technical video. In the end from a consumer point of view what would be much useful is a comparison of the economics of this approach eg 1/2 cut panels + Fronius (or equivalent with GMPPT) or normal panels with micros, or normal panels with optimisers. I don't think anyone would dispute that standard panels with a simple inverter would perform much worse than the 2 options tested in the video. Otherwise the video really shouldn't be that much of a revelation as it's really very similar to a micro vs optimiser comparo. Ultimately it's all down to how much it would cost for the conditions at a particular site.
Most excellent video! I feel much much better about my decision to go after a string based inverter.
Great video, strong, fair, honest and clear explanation. Congrats!
Thanks for putting out some really good convincing research.
great review and testing... as an installer myself this is awesome to learn and will change my advice to clients. :)
This video deserves 44 million views. Thank you
excellent proof of what the inverters today can do and the "out of date marketing" being used to needlessly grab more share of the customer's wallet. Do your research and thank you to NRG Solar from the othr side of the world ! PS sort your sound out mate. Cheers!
Thank you for this video! I'm commenting, in hopes to make this video more visible.
SUPER useful video!! Thank you very much for making it!!!!!
I'll be really interested in the results from your paralleled strings study as I have 3 strings paralleled into one MPPT and 2 strings into the other on a Fronius Symo inverter. The strings are on the four faces of my roof - the NE & SE orientations perform well however, the NW and SW orientations have shading issues at different times from street trees so your shading study will be interesting. As an aside, I don't expect the strings to perform equally as they have differing azimuths but knowing how shading of strings affects the other parallel string will be interesting. Cheers
Thanks for doing those tests. Really cleared things up for me. Feeling a lot better about my choice going with strings for my upcoming solar project.
Great to hear!
Nothing wrong with string systems. Was almost going to upgrade to an LG/Fronius, but decided on LG/enphase for a number of reasons. Was able to negotiate a great deal with a terrific company.
@@davidissko9796 Hi David, I'd be appreciated if you can share the reason of your change from Fronius to Enphase.
@@shijustin7746 Hi Justin. As above as well as panel level monitoring, ability to add panels in the future without worrying about stupid install rule changes, I like the Enphase micro system, had a string startup for 10 years prior to current system, so change was good, solid warranty and more. It's been almost 1 year since the install. Couldn't be happier with my choice.
@@davidissko9796 Hi David, thanks a lot for your detailed explanation. Well noted.
Wish I’d seen this before paying a few thousand more for solar edge due to shading concerns! Hopefully solar quotes update their information as it was certainly my go to for facts
Depends on the inverter used, as long as the inverter has a good mppt (or mentions something like shader fix) you be good
Advantages of micro inverters or solar egde is you can monitor each panel individually ark fault detection and shut down and a 5% imporvemt over a string setup in shade (or 50% improvement if your using a inverter with bad mppt that can't handle shade)
I prefer micro inverters as everything is per solar panel and no main inverter or high voltage dc to mess with
@@leexgx if you touch a metal roof with leaking solar panels is there a risk?
What do fire fighters or trades men do?
would be interesting to see you simulate a tricky roof layout to see how much benefit you get with optimisers.
Nice to see an intelligent, practical test of solar equipment - very well done.
Could you test our political parties in the same way - especially the cricket bat test??? - just kidding - it would be like plaiting fog!
This is very enlightening. Thank you so much!
You're so welcome!
Cool video, clarified me alot! Thank you for the dedication, can't wait to watch the second version with 2 strings!
Do one with SolarEdge!
Thank you so much ❤️
nice job, thanks for investigating. Be curious to see how that smashed panel degrades in the weather over time as the traces oxidize.
So glad i came across this video! Now i know what i have to choose.
The solar panels have the cells connected also in a kind of strings. They have bypass diodes to better manage the shadows.
Blimey did I just learn a lot or what! MANY THANKS mate you've also saved me a good few quid!
Thank you for putting this test together and sharing your findings, really helpful.
Great video, just what I was suspecting! Thanks.
Super interesting and very thorough, thanks for helping us understand with actual facts.
That is very valuable information for consumers! Great work.
I was wondering, since my situation is a tree at south-east, what would the results be when 30% of the panels is affected. Enphase vs string with 30% shading, I am still looking for info.
Great tests, but what panels did you use? It would make sense that string inverters perform adequately with the newer half cell split module panel designs, but does that represent all manufacturers?
1:54
Very impressive. Thank you for this excellent video and the systematic approach. It is very helpful for solar builders and privat customers showing the unneeded fear of small shadows. What I miss is a conclusion or reasoning: what causes the unexpected productivity of the Fronius system? Is it the MPP optimisation of the inverter alone as you argumented, or isn’t it also the effect of the bypass diodes and the effect of indirect light that floods the shaded areas with reflected light from the environment? I’m very curious about your comments.
Very very interesting experimentation & testing 👌👍
What a great experiment, thanks for explaining it so clearly! Too bad you're not in WA!
Really appreciate the research done here. It confirms other tests carried out that have busted the myth of optimizers/micro inverters producing significantly more power than string inverters.
I agree that despite the myth busting enphase still has its good points that make it valuable in certain scenarios. Plus it’s fairly easy and straightforward to install making it worth the added expense.
Solaredge on the other hand I would never recommend under any circumstances. Their after sales support leaves something to be desired, which given what solar edge systems cost is not acceptable in my book. And I hate how unnecessarily involved they are to install. Fronius/enphase over solaredge any day of the week for me.
Brilliant work and nice explanation 👍🏻
Fantastic. Great video mate.
Many thanks!
Thank you for your effort in this video. I'm quite far away from you (🇨🇭) otherwise, I would be your new customer. Huge thank you! 👍
Brilliant video. Thank you for sharing 🇬🇧
Fantastic study! Thank you.
Your video has been invaluable, was thinking microinverter, but thinking string more a proposition. Thanks for taking the time and testing these situations. Does this apply more so for Fronius, or other branded inverters as well? Ive been doing my research and seeing the marketing is more hype than reality.
Wonderful information. Thank you very much!
Great practical testing. Will the same apply for other brands of string inverters and APS micro inverters? We all knwo Fronius is a specialist in handling shading issues, so i wonder if other brands could reach similar results...
now that was an awesome testing
Great video. If you do the maths on the costs based on your statistics in this video you'd have to be mad as a box of frogs to buy Enphase. Over here the Fronius is £990 and the 12xIQ7+ would be £1612 + connectors + envoy. I would also draw attention to relibility and the fact that you need to get the scaffolding out and get on your roof if anything goes wrong with any of the enphase inverters which over here would be an instant £1000. If you think about the cost savings of the String inverter you could have got a 4000w inverter and got an extra 400 watts during peak sun power which would have made the enphase look frankly poor on all your graphs. SMA string inverters all the way for me here got one 15 years old still works fine - I would love to see the test with a modern SMA inverter with Shadefix to see if that's any better than the fronius.
The extra panels fixes a lot of problems.
Hahaha Hahaha.
1. Tilt frame or an EXTRA panel.
2. Efficiency falling with time, EXTRA panel.
3. String with EXTRA panel. vs Enphase.
4. Rooftop needs more shading in hot weather, EXTRA panel.
5. Morning and afternoon shoulders hours needs more power, EXTRA panel.
6. ?? , EXTRA panels
Hahaha Hahaha
The extra panel fix a lot of problems.
Hahaha Hahaha.
1. Fading output with time, EXTRA panel.
2. Tilt frame or EXTRA panel.
3. Enphase or String with EXTRA panel.
4. Shading more of the roof in hot weather, EXTRA panel.
5. More morning and afternoon shoulders hours, EXTRA panel.
6. ??? EXTRA panel
Hahaha Hahaha..
Very nice test, the only problem I know would kill a string inverter is if a panel went 100% bad and didn’t allow power to pass through.
You know you're in Australia when they use a cricket bat to break glass instead of a baseball bat
That’s because nobody watches baseball outside the USA.
@@Sashwath21 And Cuba, and Dominican Republic, and Venezuela, and Korea, and Japan, and Canada, and Puerto Rico, and Nicaragua, and Afghanistan, and Panama, and Mexico, and Taiwan, and...
@@SkepticCyclist right. So you’re saying afghans play baseball? If so many countries play baseball, why is there no baseball World Cup?
@@Sashwath21 You said nobody outside the US watches it. I gave you a list of countries where it is popular. Why do you think a lot of MLB players come from these Latin American countries, the Caribbean, Korea, and Japan? They even have their own leagues. Just admit you were wrong and move on.
BTW, they do have a world cup of baseball, it is now called the world baseball classic, formally baseball world cup. Something else you didn't know.
@@SkepticCyclist there is a difference between how many countries play vs watch baseball. That is not the point I was trying to make though. My intention was to state that the viewership of baseball is minuscule compared to that of cricket. So it’s probable that someone had a cricket bat than a baseball bat.
Good job. Great effort and result.
That's really interesting, thanks for doing the testing.
I've often wondered about my choice to go with string inverter over micros even though I do have some partial (tree) shading which varies through the year. But the Fronius just seems to truck along really well, and a micro can't make the sun shine on a shaded panel.
And yes, we've all been led to believe performance can be badly dragged down on a string system with limited shade in the wrong place but really, that's not been my experience. So unless one can exactly replicate conditions for similar system, who the hell can ever know? Well you did exactly that and now we all know.
The biggest lift in performance I got was simply having the offending trees lopped (in an aesthetically pleasing manner by an arborist) to let more light through. Winter yield improved 30%. YMMV
absolutely amazing video, thanks for your effort and sharing this information for free with us!
Excellent work 👏
Excellent information here, thank you very much!
Wish I'd seen this before I bought my system in 2014. I've got 17 Enphase micros on a roof, and one by one they are failing, 4 of them so far. Now I've learned many people have the same experience. Yes, they are warranted for 25 years, but word on the web is Enphase no longer pays the labor of swapping them out, and they will only replace the ones that have failed. I haven't got an estimate yet on replacing them but it will surely be hundreds of dollars, with the likelihood that many more will fail in the coming years. Maybe I'll just wait till half of them fail then switch the whole system to string.
Hi, any updates you can share with us?
@@joergreinicke5945 After some searching, I did find a solar installer willing to work on the system (the original installer went out of business). They found that the wiring for one of the inverters had been chewed by a squirrel and they were able to repair it, but the other 3 had indeed failed. The new installer handled the warranty claim and did get 3 new inverters from Enphase at no charge. But I did have to pay labor, total of $1150. The tech had to make 3 trips up onto the roof because Enphase demanded that he send photos of the tests he did on the inverters. That was 3 months ago. All the inverters are now working but one seems to be maxing out at ~1/4 of rated power.
Thank you for your video; nice to see some actual numbers. Any reason to believe snow would change your conclusions?
Cleared the bs up ...well done
Great test. Thank you for sharing.
Looking fwd to the Parallel strings tests. Would be good to see: 1) close but not exact wattage 2) mixed panels example array 1 270*13=3.5kw and array 2 370*9=3.3kw 3) shading.
Appreciate the videos
I have been running 2 strings in parallel to see how a real poorly design works. with mixed results. The worse I have been able to get the Fronius inverter is about 19% loss with one of the strings almost entirely in shade (the one with the smashed panel). But sometimes its almost no difference.
Excellent video. Thank you!
Thanks Eddy, great video.
Glad you enjoyed it
this video is incredible
very interesting stuff ,great video ,from the uk
Revealing information. I wonder if there are string systems which made the rumors to begin with still sold today.
Hi there! Could you do a test with half an array in the normal angle and the other half in a suboptimal angle (i.e. to simulate having panels on a North-South roof or an East-West roof)?
I have found that most solar design tools do this pretty well. I dont suspect there will be any difference to the normal losses between North and South. Be more interesting to see South facing enphase v fronius perhaps.
Excellent, excellent, excellent. You saved me many $$$$$
He put the leafs on - :-) Genius...
I would have expected to create a more real-world test that you would have a reasonable load attached. Just like a failing battery in a string can read okay until it's put under load, I would think a shaded or damaged panel would show a bigger difference.
Great video but I would like to see more than one panel shaded at a time. I am surprised at the experiment. Not what I expected.
have you considered testing when you have a few groups of 3 to 4 panels facing different orientations? They difference is when your configuration leads to a risk you do not have enough power to trigger the inverter.
Great video Eddy,
I'd like to see the data after some moisture has got into the AB style cover driven modules. Represent a bit of age into the modules.
Maybe some lower numbers on the strings too.
Love the setup
Try this test with 3 a 4 panels a string (what a lot of houses has), not fully sure but when low light / shade like in the winter it might not get to start voltage of that thing. But yeah, both are great.
After talking to multiple installers, watching many videos and reading articles about micro vs string inverters, I bought into the marketing as well. Thanks for doing this test and video. I was wondering how it would be if one of the panels malfunctions or optimizer/micro-inverter stops working, how it will effect it, I'm assuming minimal as it would be similar to the "micro-cracks" test.
Great video. If you can, kindly repeat same test with the fronius plus optimisers or same test with other brands of string inverters, SMA, Victron easy solar, Huawei, Goodwe, Sungrow etc.
Sorry, the testing station has been removed. I look forward to others having a similar a go with the inverters they want to look at.
Hi Eddy, exceptional experiment, very convincing! How do you see the influence of the bypass diodes compared to the MPP optimisation of the Fronius inverter?
MPPT has been done by all inverters from the start. So that can’t really be the difference maker.
@@JasperJanssen : Of course it can. MPPT algorithms have improved greatly since the first efforts (e.g., local vs. global, etc.). That is why some YT videos claiming large losses for string inverters are misleading (one from the EEVBlog guy comes to mind) because they are using either older inverters, or haven't updated their firmware with newer algorithms, or haven't enabled an option in the inverter setup. A modern (within the past 2 or so years), brand name (SMA, Fronius, Sol-Ark, etc.) string inverter with the latest firmware installed partnered with modern solar panels (including bypass diodes, & maybe half cut cell design) should perform quite close to a microinverter setup for a much lower cost. And if you intend to include battery storage/backup to draw power during evening/night hours, the string inverter makes up all the difference (and probably more) because you don't have to invert twice just to charge the batteries.
Give Alan Border a run for his money with those hits Eddie :)