Solar Panel Shading (Part 1): Are Optimisers and Micro inverters Worth It?
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- čas přidán 5. 06. 2024
- Optimisers and micro inverters are said to improve your solar output in the event of shading. In this video, we look closely at those claims and if they're worth the extra cost.
Chapters:
0:00 Intro
0:37 Advertised claims
2:34 Busting the myth!
3:31 Built-in panel shading management
10:22 Shading experiments
13:30 Optimisers and microinverters
17:09 Diffuse shading (trees)
18:17 Pros and cons
SolarEdge marketing material on shading:
• Boost your PV system w...
Tigo marketing material on shading:
• About Tigo Energy
Enphase marketing material on shading:
enphase.com/en-gb/installers/...
Interactive utility to show the effect of shading on a module and an array:
www.pveducation.org/pvcdrom/m...
Real-world shade testing of optimised and non-optimised arrays:
(“Micro and String Inverters in the Shade - Testing the True Impact of Shade on Solar Panels” - NRG Solar)
• Micro and String Inver...
Built-in solar panel shading management in action:
(“How Shade Effects Solar Panel Production” - Paradise Energy Solutions)
• How Shade Effects Sola...
If you're getting a lot from my videos, and would like to support me in my efforts to help everyone, here are a couple of ways to do this:
1. You could www.buymeacoffee.com/GaryDoes... :-)
2. If you're thinking of switching energy supplier to Octopus Energy. If you call them and give them my referral code ("blue-wind-201") and my name ("Gary Waite") and we'll both get a £50 credit to our accounts as a result! share.octopus.energy/blue-win...
I believe Octopus Energy is doing more than any other energy company in the UK to take us forward to a bright renewable future, and I'll make making reference to them and their initiatives in future videos.
#solar #panels #shading
For business enquiries:
Email: me@garydoessolar.com
(Please note: despite my channel name, I don't provide, nor consult on, solar installations)
(c) 2022 Gary Does Solar. All rights reserved.
DISCLAIMER
Whilst every effort is made to ensure the accuracy of the content in this video, no warranty for that content is provided, nor should it be implied. Viewers acting on the content, do so at their own risk. - Jak na to + styl
Best video I've seen discussing this topic. Well done.
Hi David, that's praise indeed - thank you! :-)
An excellent presentation. In fact that’s one of the best presentations on the subject of partial shading that I’ve seen. I was aware of the bypass diodes, but hadn’t considered the impact on the larger array.
I think panels have evolved a little to include “half cut” cells. I think they run the bypass diodes up the middle of the panel, essentially doubling string number, and halving string length. It improves two attributes:
- better partial shading performance
- reduced diode hotspots, thereby improving panel life
That diode heat loss can be a real panel killer.
I did my own shading tests, which I think is in my Spring/June video this year. The direction in which shading is uncovered has a big impact on performance.
Coming from you, Anthony - that's praise indeed! Thank you. I might do a follow up on shading when I've collected enough feedback etc. and I'll be sure to include half-cut cells :-)
And I remember your shading tests - I can't wait to be my own setup installed in January to do some of my own (I'll have relatively easy access to the panels as I have a number of Velux windows on my roof). I've had a bit of a nightmare with my solar journey, which started back in March!
Let me know if you're interested to do something together on CZcams at any time - I'd be game on for that.
Agreed, well presented. I’m breathing a sigh of relief knowing that I did do the right thing putting Enphase on my second array ( split across SE and SW facing roofs with chimneys ) Thanks
Direction of shade encroachment is indeed important. Most PV modules are wired as Gary illustrated so that the long edges each fall within one bypass diode zone. This is good for commercial ground mounted arrays facing South and with modules racked in landscape orientation. In that way the shade from the next most southern rack activates the minimum number of bypass diodes
how many strings can you break an array into? it seems like more wiring would be cheaper than optimisers or micro inverters, but there is a reason there are so many panels to a string and then the strings are in parallel; what are the limits?
Hi Scott, so it depends on your inverter. Most inverters only support two strings, but some can support three (or more). For each string, there is a minimum voltage level requirement before generation starts, so ideally, you want a lot of panels on each string to achieve that minimum requirement for longer in the day, especially if it’s cloudy.
There is an upper limit on the voltage (and also current) which will be different for each inverter manufacturer.
Gary, it is always such a pleasure to get the alert that you have a new video out.
Hi Nick - your comment has made my day! 😀 thank you!
My next video will be a very short one talking about the difference between kW and kWh,…. and maybe a bit about voltage and current in there too - all using the water analogy 👍🏻
Really appreciate the hard work and depth of information you provide in your videos. An invaluable source of knowledge, thank you.
It is my pleasure, Paul - yeah, hard work - but it's great to hear from people, saying my videos are helping them out :-)
Thank you Garry, the way you explain and present it is just invaluable! We need more heroes like you on CZcams! 👍🏻
Hi Roberto - you’re far too kind, but thank you 🙏 😊 I’ll keep the videos coming…
Another fantastic video thanks Gary! Your graphics and commentary is superb. Greetings from South Africa.
Hey Andrew - thanks for the great feedback :-) Hope all is well with you!
Without a doubt, the best explained series of videos on solar PV! Thank you Gary
Hi John, that's praise indeed - thank you! And all the best! :-)
Fantastic video to help understand what's going on with string, micro, optimizers, etc. Thank you!
That's great feedback to receive, Jean-Marc - thank you! :-)
As usual another extremely informative and useful video, I suspect it could save me a packet when we finally "take the plunge" early next year.
However I suspect I'll be rewatching all of your videos before we make a final commitment .
Thanks again Gary.
Thanks - that's so great to hear I've been of help to you :-) Good luck with your solar journey!
Very clear presentation Gary. Well done. Subscribed
Thank you for subscribing - that gives me the drive to keep going! :-)
Thanks for this, I saw the NRG Solar video, but it just raised more questions. It's all much clearer after you explained how the bypass diodes work.
You're most welcome, Dominic. I'm really happy to hear this feedback :-)
Excellent explanation. Best video on CZcams explaining how they work and the pros and cons.
Thank you Dominic - that means a lot to me! 😀👍🏻
As having no experience in this field you’re videos have given me a better insight to what I need to know before I make a final decision on what to install,I wish to thank you for making it a lot easier to ask the relevant questions,excellent videos
Great to have been able to help out, Michael - thanks! :-)
Best and easyest to understand video about this topic.
I've just subscribed.
Thank you for your work 👍
That’s praise indeed! Thank you, Alex 😀
Great video, Gary. The time and care you clearly take to produce such professional presentations is definitely to your credit (not entirely sure about the start and end music, but hey that's personal taste!)
Hi Chas, thanks very much for taking the time to tell me this - it really means a lot.
I agree about the music - it's a bit tacky and I'll change it before long! :-)
Chas Winder: I agree, good comment.
Quite a good video. I'll add a few other points that need to be considered:
* When designing a string without optimizers, make sure that there is plenty of voltage margin verses the optimal 'operating' MPPT range of the inverter. For example, if the inverter's optimal MPPT range is 300-500V, you don't want the total operating voltage of the string to be anywhere near 300V. You want it to be higher so partial shading does not reduce the voltage to the point where it leaves the MPPTs operating range. Of course you also have to make sure that the string's open-circuit voltage does not exceed the inverter's maximum voltage (for an inverter like this, typically 600V). So in this example, having the nominal operating voltage be, say, around 450V, would be ideal.
* Not all MPPT controllers are the same. When partial shading occurs, it changes the voltage-current curve that the MPPT controller sees. Sometimes the partial shading can cause a 'double peak' on the curve where one peak produces far more power than the other. If the MPPT controller fixates on the wrong peak, system performance can degrade well beyond what it should. So, for example, SMA's high voltage string inverters will do a periodic voltage sweep (usually every few minutes) to make sure that the MPPT is servo'd on the correct peak.
* In variable shading conditions... for example, foliage on a windy day, the MPPT point may move around more quickly than the MPPT can track, resulting in additional performance loss. Optimizers and micro-inverters are able to track these quickly-changing conditions far more quickly than whole-string MPPTs can. But in most cases, such effects are minor anyhow.
* People often make the mistake of paralleling multiple strings into a single MPPT. This results in far worse losses under partial shading conditions because any shade will cause the combined MPPT point to be non-optimal for BOTH strings. Thus, when designing a string system, always be sure to give each string its own MPPT and do not use paralleling (i.e. don't use a solar combiner box to parallel 2+ strings together). In modern day, it is really easy to dedicate one MPPT to each string, but older string inverters often had only one real MPPT controller.
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* Also, note that micro-inverters have the additional problem of back-hauling 240VAC instead of 400VDC, which means either (a) higher losses on the return wires or (b) requires lower-gauge (thicker) copper wires to backhaul the same amount of power.
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The bypass diodes are typically schottky diodes, each with a 0.3V volt drop when operating. Solar panels typically have three such diodes so if a panel is mostly shaded you not only lose the power from that panel, the string as a whole would also lose another 1V on top of that (per mostly-shaded panel).
Bypass diodes basically allow current to flow one way with a voltage drop of 0.3V to 0.7V. The solar panel itself develops a voltage across the panel which puts the bypass diode into reverse bias, which basically turns off the bypass diode. When shading occurs, the open-circuit voltage of the shaded panel is STILL LIKELY TO BE VERY HIGH, far more than 1V. However, the load on the panel (in shaded conditions) quickly drops this voltage as the panel is unable to support the current the other panels are generating, which takes the voltage below 1V and essentially turns on the diode, allowing it to conduct the other panel's current.
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So, generally speaking, it almost never makes any sense to use optimizers or micro-inverters, but one must still be a little careful when designing the string system to avoid the pitfalls mentioned above. The only situation where micro-inverters or optimizers make sense are in quickly-changing shading conditions because their individual MPPTs can react more quickly to the changing conditions. But that's it. I definitely prefer high-voltage strings over optimizers or micro-inverters.
-Matt
Wow - this is great insight! Thanks for taking the time to share with me. I'm considering a follow-up video on shading in a couple of month's time - and if it's ok with you, I'll try to include this insight (with credit given of course).
Great analysis. Maximizing the MPPT voltage is the key it seems, which means longer (i.e. higher voltage) strings are better. This also has the effect of extending the operating (time) window of the system (i.e. inverter on/off) closer to the peaks of consumption (i.e. morning and afternoon) so producing more useful output. Optimisers actually reduce the operating time window by reducing the string voltage slightly (thus resulting in later 'inverter on' and earlier 'inverter off' times), even when completely unshaded. Bit of a chocolate teapot IMO.
As far as I know there is only one micro inverter producer with true 400V micro inverters, AP Systems manufactures them.
Losses are higher with 400VDC compared to 240VAC no? Transmission line theory
@@whirled_peas Didi you get that backwards? The higher the voltage, the lower the losses, not the other way around. Losses are governed by P = I^2 * R (power = current squared times resistance). For voltage and current, transmitted power is P = I * V.
So for the same power transmitted, the higher the voltage, the lower the current on the wire. But losses scale to the square of the current so if you hold power the same and cut the voltage in half, losses will increase by 4 times.
For 400VDC vs 240VAC, the 400VDC line will 60% lower losses along the wires.
Of course it depends which country you live in. In some countries the utility connection to the house might be higher. But in most it hovers around the 200-240VAC range.
This is also why advertised efficiencies for micro-inverters and optimizers are usually somewhat disingenuous. For micro-inverters it is because they don't count the higher losses on the back-haul. And for optimizers it is because you still have to add-in the losses from the inverter that the optimizers are tied into (thus going through an additional conversion).
-Matt
good video. When we set up our solar company, we had two systems installed. one partially shaded with microinverters, one with a string system also with shade. We demonstrate exactly what you are showing, but live in real life situations on our own home. Hearing from clients who have upgraded older string systems to Tigo and EnPhase is a real joy.
Thanks for watching my videos and taking time to comment. I’ll be doing a follow up on the shading one, and it sounds like you’ve great insight! If there’s anything you’d like me to cover in that, just let me know 👍🏻 All the best with your company! 😀
Thank you - terrific explanations and perfectly accompanied by the simple graphics. You have a new subscriber.
Cheers Malk - that's fantastic feedback, and it's great to hear that you're finding my videos useful :-)
Excellent video, thank you. I was fretting about cable shading on my newly installed array, and couldn't understand why my panels were still generating when some of the stuff I'd read said they wouldn't. This has explained it in simple to understand language. Thank you.
You’re most welcome. Glad to have helped you in your solar journey! All the best for the future 👍🏻 😀
Excellent presentation. Nice and simple: the way true understanding always is.
Hi Doug - thanks for the great feedback! 😀👍🏻
Thanks Gary. This video is a model of clarity.
I have recently been mulling over the question of optimisers but, aside from generic 'marketing-speak', I had found very little in the way of hard information.
My gut feeling was that, for my installation, optimisers would offer little benefit and your helpful video has backed this up and saved me quite a bit of cash 😀.
Thanks for the kind words, John - and great to hear that I've been able to help you work through some of the decisions you have to make.
What I have found with my own testing is don't buy normal panels, buy half-cell split panels, or BF panels, as they don't souther nearly as much from shading, and even on an overcast day they produce nearly as much power as my 2 year old LG panels do in full sun, and they have expanded my day by almost 2 hours. Thanks for this video, I found it very helpful. Subed.
Sounds like great advice!
Bifacial panels are less vulnerable to shading? Why is that?
Great Job Gary!
Super presentation love the voice tone + explanations !!! BRAVO
Thanks again! :-)
Nice explanation and definitely food for thought when deciding on the orientation of the panel based on likely hood of shading. If a wall or hedge is likely to shade the bottom of the panel late in the day it would make sense to have the panel in landscape orientation so only one string is bypassed and not all of them.
Hi Peter, totally agree! 👍🏻
A very informative video that helps to clarify the pros and cons.
You're most welcome - thanks for taking the time to comment :-)
I've just read through most of the comments on this excellent presentation/video. There is really very little I could add. Extremely informative, challenging & clarifying supplier based information; excellent graphics. I suppose in summary, I feel in safe hands, without a hidden agenda. Thanks very much 🙏
Wow - thanks, Nic. That's very kind of you to say. I'll try to keep up the level of quality :-)
@@GaryDoesSolar You started out with a very high bar 😉
Brilliant content as usual Gary. This is the true spirit of the internet.
Hi Jamie, thanks - that means a lot! :-)
Well explained, thanks from all of us and great initiatives
You’re most welcome Nilesh 😀
Loving your content Gary. Very clear and to the point. Keep them coming.
Thank you! This particular video took quite a while to put together! I'm hoping to get more efficient at the recording/edit.
@@GaryDoesSolar You're doing far better than I am at editing. Love the animation work.
You're too kind, but thank you 🙏
This was incredibly useful thanks. Great to get the technical detail. Cheers.
You’re very welcome! Thanks for taking the time to comment 👍🏻 😀
Another great video. Informative and unbiased.
Thank you! I do pride myself on being as objective as I can 👍🏻
Excellent and so very scientific. Many thanks Gary!
You're very welcome, Andre - glad you liked the video :-)
Fantastic video and well explained and illustrated.
Thank you Morne! :-)
Good video and well explained, one that I can point customers to!! been on about this for years, in these situations we parallel connect if some of the array will be shaded, we also combine series and parallel connections. Keep up the good work
Thank you so much! Yes, please feel free to share my videos with your customers. My next one will be explaining all the energy terms: kW, kWh, voltage, current, single phase, 3-phase, frequency etc.
Very clear and detailed explanation. Thanks!
You're very welcome, Stijn :-)
I was sceptical when my installer suggested optimisers back in 2013 but now having the data for every panel (occasional shading depending on the time of year) each panel varies by quite a degree in terms of output even in non-shaded conditions (i.e. two adjacent panels in summer for example) - if it was a single string, the whole array would have been pulled down by the weakest panel and thus over the lifetime of the array this could well add up to 100s of kWh - in close to 10 years this is very apparent and so I’m glad I went with them - I’m squeezing every W out of each panel so they have paid for themselves in their gains from my calculations…each to their own however. That said, back in the FiT days, the upper limit for the highest rate was 4kWp so there wasn't as trivial as adding more panels - even then the added cost for the panels and mountings might outweigh the benefits of the optimisers/u-inverters imo
Bit long winded but, I have data from the first 4 years - the install was intended as a bit of an 'experiment' as my installer was explaining the virtues of thin-film panels over mono-crysytalline - they can have better low light output and better peak performance but at the expense of being bigger panels (hence more cost to install) - I suggested we went 50/50 on the same roof and I share the data with him - 1.95kWp Solar Frontier and 2kWp of LG - the difference has been pretty self evident though the LGs actually perform marginally better in low light (slightly better yield on dark days), the SFs better in peak conditions due to the 'light soak' effect. Solar Frontier did a case study at the time (not sure if still on their site) though I calculated gains of around 4-5% for the same kWp (they claim 10%)
By way of example, on a crappy day in January 2016 my best thin film managed 133Wh, the worst 65Wh, the LGs were 96Wh and 82Wh respectively. On a good sunny day in July same stat - SF 2.4kWh vs 2.2kWh and LG 1.72kWh vs 1.65kWh so there is variation between panels - similar to the performance of microprocessors where they are categorised for sale depending on bench testing - for the thin-films at least this is very apparent, the LGs are much closer but again over a lifetime, those few Wh add up - I want to harvest every electron I can and on balance between cost and material input for the optimisers, they seem to be doing their job! (as an aside, I noticed quickly that the SF panels wouldn't 'come online' until they reached around 10-12W of power versus the LGs which started at 2-3W - I shared the data with SE and they sent over a newer version of the optimisers that were on the thin films as they have a Vp higher than monos - that solved the 'low light' problem as they all come on at around the same time now - it was a faff to replace but fortunately it's a bungalow so I just said to my installer that I'd do it myself rather than them get scaff back up etc)
Thanks for taking the time to make this detailed comment. It's great to hear that it all worked it for you :-)
Thank you very much indeed Gary; really well made, clear, easy to understand, I’m formative video.
You're most welcome, Richard :-)
Thanks again Gary- so much useful information!
Thank you for watching, Paul - I'll keep the videos coming :-)
Wonderful. Great information clearly explained, thanks bud!
My pleasure Bob - thank you! :-)
Really well explained. Great job.
Thank you! :-)
Best video yet Gary 👍
Thank you! This particular one took quite a while to put together! I need to try and get more efficient with the recording and editing - that's just as hard as getting the content together! Lol
Thank you. A very timely video for me as I'm in the process of comparing various quotes at present. I have tree shading issues so have been querying why optimisers are in/excluded from various quotes and why some quotes are only including partially optimised Tigo solutions. This is probably as clear an explanation of all the regular systems as I've seen (several compare Enphase and SolarEdge but very few include Tigo in the mix, which is what most companies are using in their quotations).
Keep up the great work.
Thanks very much for the kind words - yeah, it's a real minefield out there, and hopefully, I'll continue to be able to demystify solar in my future videos :-)
@@GaryDoesSolar The good news is that I'm not yet an Octopus customer, so will definitely use your referral code when I'm eventually able to make the switch (not just for this video, but the entire series to date, which has been excellent). Not sure if you're aware, but they're currently closed to new customers until Octopus find a way to make them compatible with the Govt Energy Support Payments, as there's currently no way to include these on fixed rate tariffs, which is what the Go and Agile tariff rates are.
It's very obvious how much work goes into these videos, so being able to use an affiliate code like this is at least a way to show support.
That would be very much appreciated, @@RiffMan117 - thank you! I’m using really basic equipment to make the videos (would you believe all the animations are in PowerPoint?!) My audio is all over the place, so I’d be using referral monies to buy better equipment 😀👍🏻
Good explanation and analysis of the pros and cons. Thank you.
Thanks John - that means a lot as I’m a big fan of your videos - you’re very calm and clear! 😀
@@GaryDoesSolar ah bless you. Thank you.
Thx. Great.
Very clear and educational. I have been searching this and now the yt algorithm keeps popping up these vid s about string vs optimized panels.
This one is very good!
Thanks - it’s really hard to get traction on CZcams as there are soooo many videos being produced all the time! Great to see that my videos are getting some exposure 😀😀👍🏻
Great information Gary, very clearly explained, thank you
You're most welcome - great to have feedback like this :-)
Hi Gary,
As everyone else has said, this is another brilliant video - perhaps the best yet. The fact that you are very even-handed means, as you say, viewers can (and should!) make up their own minds on the subject.
I've just placed an order for a 16-panel (8/8 east/west array)/5kWh battery system. At this time of year, we will have heavy shading on the west array (from about 2.30pm until about 5pm) from a large oak tree in a neighbouring garden.
I've asked for Tigo optimisers on all of the west panels. We will have some shading on four of the east panels during the morning from a chimney. After some thought, I've decided to add optimisers to those four affected panels as well. I'm in discussion with Tigo at the moment about whether the Tigo Access Point (TAP) on the west array will be able to manage the additional four east panels. (The TAP connects to each optimiser by WiFi and is connected to the control gateway by a cable).
When I started to watch your video, I wondered whether I'd specification the optimisers unnecessarily, but by the end my opinion is that for my situation I have made the right decision.
Just a note on the point about costs: I've done a quick search for Tigo optimisers and the CCA (gateway) & TAP are available for about £60 & £400 respectively. Not an inconsiderable overall expense, but one which should, in my case, have a reasonably quick payback (I hope!).
Hi Phil - thanks for taking the time to comment in detail about your own situation. Yeah, I agree - optimisers are a good solution for you - and I would have taken the same approach. I'd love to hear how it all goes! :-)
Hi Gary [- Truly EXCELLENT video - concentrating on technical detail on how panels work and the effect of bypass diodes. As a professionally qualified electricaland electronics engineer- I think the solar trade in general needs far more of this excellent level of instruction. ( Sadly lacking -you only need to read some of the forums to see how poorly solar power is understood,
Having taken many so called "solar installer courses" from well known manufacturers - this video mostly stands head and shoulders above those - in terms of accurate well presented technical detail - not so such as to baffle people - but more than enough to understand properly what is going on
Excellent !
Thank you, Eric - that's praise indeed!
I'll keep working on new videos :-)
indeed Eric!
Thank you for an well presented (and correct) explanation of solar shading.
Thanks Tom - your comment is very much appreciated :-) I'm making a follow-up video on shading shortly...
Quite frankly this is exactly what I have been looking for. Excellent presentation, and excellent communication. Having had solar for three weeks now, no micro inverters and the potential of chimney shading, this video has totally relaxed my worry about not asking for micro inverters. Thanks Garry - you have a new subscriber!
Thanks Barnaby - much appreciated! Glad to have put your mind at rest 👍🏻
@@GaryDoesSolar same situation here. I'm glad I've not performed a costly installation of optimisers on my 7 year old system. As you point out, the extra complexity increases your chances of failure and the benifits while there are not so big as to justify the cost.
Also, very nicely paced clear explanation with good illustrations.
Thanks Miles 😀 I’ll try my best to sustain this with my planned future videos 👍🏻
There are other reasons you would want to go with solar edge optimisers, #1 being the ability to oversize your panels and get access to dc power to charge battery or ev. Absolute game changer that your string inverters cannot entertain unfortunately
Your channel is probably the best source of technical information about solar and battery systems on CZcams right now, Gary. Many thanks for making such thorough and clear videos, I've learnt a lot from them.
Thanks Tim & Kat - that’s really kind of you to say 😀 When I looked into Solar for my own house, it was a real minefield of information and misinformation, so I thought I’d try to save everyone some time. Of course, once you release one video you kind of get hooked and spend countless hours putting together more 🤣🤣 Btw, I watched all your videos over the past few months. And am totally jealous of the 30% gas one - wow - and 1/3 million views and counting! 😳👍🏻 Keep up the great work!
@@GaryDoesSolar well, the time is very well spent, your video production quality is off the charts. I find it very amusing that you've been watching our videos in return. Ours are definitely a lot more rough and ready! It's funny, that first gas saving video was sort of intended for family and friends but then it went exponential which came as a bit of a shock. It turned out to be a double edged sword though as although it allowed us to join the CZcams partner programme within two weeks it also came with a huge number of comments, which was a bit overwhelming. Most were very positive but a non-trivial number accused me of spreading misleading and dangerous information and even that I was going to kill people with my bad advice! It didn't matter that I got that advice from the Heat Geek channel and it was all perfectly accurate, some people still thought I shouldn't be giving advice if I wasn't a professional heating engineer. Oh well. I turned off the comments in the end and immediately felt a lot better! The internet is a funny thing, for sure. Our more recent videos are definitely a lot less controversial, thankfully. I look forward to whatever subject you tackle in your next video with great interest.
Thanks - that’s very kind of you to say. I’m certainly learning as I go. I need to improve my audio equipment as it’s different on and off camera. All the animations are done in (would you believe) Microsoft PowerPoint!
Sorry to hear you were getting some adverse comments. This is certainly one of the hazards of publicising any kind of content - and yeah, with the reach you got with that video, the level of comments (across the spectrum) was always going to be high 🤣
I’m still able to respond to each comment, but if the channel grows further, I know I won’t be able to. What’s great is that the comments give me ideas for future videos - the shading topic is a great example as in an earlier video I said something about shading that turned out to be a complete myth! Lol
What I like about your videos is that you’re highly relatable for everyone watching. And the fact that it’s “rough and ready” just adds to that. All the best with your channel. And I should be releasing a couple more videos soon (I’ve a back list of bay least 10 ideas so far - crikey! Just wish I had more time to actually make them!)
@@GaryDoesSolar PowerPoint! That's amazing, I never would have guessed. They're very effective, I have to say. Do you create the actual graphics yourself too? And I'd say your audio is fine, the difference between on and off camera is very marginal and hardly noticeable unless you're listening out for it.
By the way, if you ever need to do any 3D models or animations give me a shout, I've got some experience with that sort of thing (do a Google search for Stone Baked Games, my other side project). Something I'm planning on doing at some point is creating a sort of 3D visualisation tool of a house with solar panels and adding a (reasonably) physically correct day/night cycle that can be varied by day of the year, so that folks could see the angle of the light landing on their panels at different times. I've worked out the maths, I just need to sit down and build the actual project! In the mean time I've been using the on-line tool you suggested in one of your previous videos, which is very handy.
I also try to respond to all the comments I get (well, most of them) and at the moment it's just about manageable. But as you say, if the channel keeps growing that might become increasingly difficult. Thankfully the more recent videos have been almost exclusively positive, which I'm glad about.
I'm glad you like our videos. I was hoping that they would appeal to some people at least and that does seem to be the case, thankfully. Like you I have ideas for loads more, and for every video I publish I get ideas for another five (often from what people say in the comments!). Keep it up, you're doing good work that I'm sure helps a lot of people, myself included!
Hi Tim, thanks - yeah I create all the graphics myself too - again in PPT - but now I’ve seen what you’re doing with SBG, I’m clearly an amateur!! And funny that I saw the sphinx and pyramids in the sunbeam trailer as I’m in Egypt just now! 😀
I like your 3D solar utility idea and I’d of course be happy to promote such on my channel in due course if you’d like 👍🏻
Great video. I might have added that the situation described applies to an array of identical panels mounted in essentially the same place which is probably the case for most new installations..
Thanks, and agreed 👍🏻
Great video, thanks!
You’re most welcome 😀
Thank you for that very useful information. Great video as always A++
You're most welcome - thanks for taking the time to comment :-)
This is a must watch video. Thanks a lot.
You’re very welcome - thanks for taking the time to let me know 😀👍🏻
Very informative. Thanks Gary
Thank you - this one took quite a while to put together!
@@GaryDoesSolar Yep it takes more energy and time than what we could see and think. Great job and thanks again.
An excellent presentation!
Thank you! Part two on shading hopefully coming in the next couple of days….
Another very informative video - thanks very much.
Thanks Adrian - this one took quite a while to put together!
@@GaryDoesSolar I'm sure it did as you can tell by the graphics and references you found to back up your explanation and reasoning and what people don't understand is the time ot takes to find what you are after and then to cros check what you have fojnd to make sure that it is correct. This takes ages. People in general just see the presentation and just assume that it has been grabbed and don't realise that research takes an incredible amount of time. Probably due to a lot of people just taken a source at face value and don't cross check. No, it is a very informative video as your others have been btw.
Love the explanation...well presented.
Thank's John! :-)
Very well explained,thank u sir!
You are most welcome! :-)
Hi Gary. Thank you so much; these are fantastic videos which are so much easier to understand than just reading manufacturer's literature. I do have a question/observation. I've watched your earlier video 'How to choose SOLAR wisely and avoid costly mistakes' where you explain what each component does in a SOLAR system i.e., Solar panel, Invertor and batteries. In the Solar panel section, you mention that shading one panel will adversely impact all the solar panels in the series which suggests using optimizers and/or microinverters is the only solution to reduce the impact of shading. However, your video 'Solar panels shading: Are optimizers and microinverters worth it' you clearly explain that electronic protection measures are in place by having the bypass diode added to each array leg suggesting that optimizers and microinverters are probably not worth the investment as the bypass diodes do a great job. Also, the cost of replacing the optimizer could be high for the reasons you explain. Maybe it's just me but I felt the videos slightly contradicted each other in the Solar panel sections. Let me know your views. Keep up the great work. Cheers
Thanks David, for the kind words. Really great to hear you’re loving the videos 😀
Yes, you’re right. In the earlier video, I feel I was duped by marketing material and also many CZcams videos that claimed shading on one panel would affect all the others. It was only when someone mentioned bypass diodes in the comments to that video, that I thought I should undertake my own research to get to the bottom of it all. And I’m glad I did!
Now, I added a correction to the first video but I guess it was not prominent enough - it should state “CORRECTION“ at the appropriate point in the video with a link to the later video…
Very professional. Thank you.
Hi Jen - that's very kind of you to say - thank you! :-)
Thank you so much Gary. Very useful 🙏
My pleasure 😀👍🏻
I did a 2 panel test in series hooked up to a Bouge RV MPPT. Both panels getting full sun I covered one with a blanket. It took the watts to near zero for about 20 seconds but then the mppt adapted and gave about half of the 2 panel wattage. I think the whole panel has a bypass diode too that keeps one shaded from taking out the whole array.
Two panels in Parallel reacted to one fully shaded panel a lot faster almost immediately halving without going to zero for 20+ seconds. This convinced me that parallel is best for small RV 12v systems. You never know when you will turn and have shade across a panel. Losing 20-30 seconds of power everytime would add up. I also saw an increase in heat for the mppt controller with the series due to higher voltage having to be downstepped to 14.4v. However Series is a must for higher voltage battery systems (24v or higher) or you can use higher wattage panels as an option.
Thanks for sharing the results of these experiments! :-)
A very good quality presentation.
It might be worth checking the minimum operating voltage of the string inverter, as this may come into play if the shading is across several panels stops it from operating all together. If you have dramatic shading, like I do on my garage and only space for 6 panels, then Enphase IQ7+ microinverters are the only real option.
There is also something called sub-panel optimisation where by you can replace the 3 bypass diodes with a small circuit that will optimise each of the 3 strings of cells. These were in the form of the Jinko Cheetah Maxim optimised panels - which I believe are now obsolete. It is a pity they did not continue this idea with more panels. So I am looking at building some of the modules to retro-fit to a test panel, the IC that forms the heart of this is the Maxim MAX20800. This involves removing the silicon potting compound and diodes and fitting a small PCB and re-potting it to waterproof it and conduct any heat away.
Its worth also mentioning that the panels do not need to face the sun to produce power, as I have mounted a panel on the west vertical wall of my garage to take advantage of the setting summer sun, but even in the autumn/winter when the panel does not get any direct sunlight, I can still see perhaps 160Whr on a part sunny/cloudy day with the sun bouncing off the clouds and 60Whr on a clear blue sky sunny day.
Hi Rob, thanks for the kind words. And thanks also for this detailed comment. Lots of information in there for me to work through, especially as I'll be making a follow-up video on the shading topic soon... I love it that you're not frightened to get stuck in on the bypass diode circuitry! :-)
Great video Gary!
Thanks Phil - this one took quite a while to put together!
@@GaryDoesSolar Yes, I can imagine that it was a lot of work. Excellent job Gary!
Well presented Gaz
Thank you! :-)
Very clear and informative. One advantage of microinverters is their ability to shut off power when the grid goes down. This is a safety issue and a requirement here in the US. If firemen need to go on the roof, series solar panels can present a dangerous HV DC.
Thanks Ken, for the kind words. And thanks also for highlighting this extra benefit. Although the videos on microinverters I've made up to now have been focussed on shading, I am going to make a video dedicated to microinverters, covering all of their benefits - I'll make sure to include this one :-)
very useful and informative indeed. Thank you.
You're very welcome and many thanks, Andy :-)
Another brilliant video Gary. I look forward to seeing what you tackle next. I wonder if you'll get any feedback from SolarEdge/Tigo/Enphase?
Hi Tony - thanks very much. Now, I've not heard anything yet - and hoping they'll will see I've been objective and also have simply quoted their own materials. I'd certainly be happy to record a video with them if they wanted to extol the benefits of their products... :-)
Excellent content well presented - thank you
Thanks Andy - this one took quite a while to put together!
Interesting conclusion; one of your cons is actually our pro.
We went for microinverters. The reason being resilience and redundancy. As I understand it, a single microinverter or panel failure will have an impact only on that single element. The rest of the array will function the same. The microinverters are also separate from our battery system, so there's no single point of failure that could bring the whole system down. The microinverters having a 25 year warranty also gave us greater confidence in the reliability of those parts.
Our roof is really hard to access. So a failed panel, inverter or wiring damage (damn birds) would be a huge expense. So, whilst the microinverters do indeed give more points of failure, a single failure can wait until we have another good reason to access the roof as the overall impact is minimal. It also means a battery inverter failure wouldn't impact solar and vice versa.
There's also a chance that I'm wrong and I've spent the extra money for no reason, lol.
Thanks for sharing about your installation - I'd love to hear how it performs over the next few years - will help others who are apprehensive about microinverters...
@@GaryDoesSolar I'll let you know if there's anything of note. We have had it around 18 months and the biggest problems have been administrative.
Very informative, thank you. If we ignore reliability of the bypass diodes for a moment, it looks like only part shading that does not trigger the bypass diodes is an issue in terms of generation (overall the system generating less than it actually could so to speak.)
A quick search online suggests that bypass diodes can/do fail, and avoiding unnecessary load on them might be beneficial. In which case optimisers or micro inverters might have value in terms of long term maintenance/reliability, quite aside from slight increases in generation. HOWEVER, I am an amateur and quick searches online by amateurs often lead to mistaken beliefs…
I have a house with quite severe local shading on much of the roof, that varies through the day and seasons, so have a more complex situation than anyone with no local shading issues. My feel at the moment is that I will be using optimisers or micro inverters.
Thanks Glenn - I agree with your analysis. And if my situation was similar to yours, I'd be looking at having optimisers too.
Great explanation. Thankyou
You’re very welcome, Scotty 😀
This is helpful. Seems to me that in most cases it's far better to simply buy more panels (as long as they fit) for a roof, rather than optimizers.
Thanks Don - I was careful not to draw firm conclusions one way or another. But I did want to get the point across that any improvements with optimisers are only marginal. If I had shading on my roof, I would like get optimisers for the affected panels, even just for the monitoring.
@@GaryDoesSolar Hi Gary. Thank you so much; these are fantastic videos which are so much easier to understand than just reading manufacturer's literature. I do have a question/observation. I've watched your earlier video 'How to choose SOLAR wisely and avoid costly mistakes' where you explain what each component does in a SOLAR system i.e. Solar panel, Invertor and batteries. In the Solar panel section, you mention that shading one panel will adversely impact all the solar panels in the series which suggests using optimizers and/or microinvertors is the only solution to reduce the impact of shading. However, your video 'Solar panels shading : Are optimizers and microinvertors worth it' you clearly explain that electronic protection measures are in place by having the bypass diode added to each array leg suggesting that optimizers and microinvertors are probably not worth the investment as the bypass diodes do a great job. Also, the cost of replacing the optimizer could be high for the reasons you explain. Maybe it's just me but I felt the videos slightly contradicted each other in the Solar panel sections. Let me know your views. Keep up the great work. Cheers
Misses out a lot about optimisers here.
The string number lengths can be much longer, meaning that much more often you can have just one string down to the inverter.
You can also parallel different length/orientation strings together (some conditions apply)
Also orientation of panels in the string doesn't matter so much due to individual mppt.
Open circuit voltage is only 1V per panel giving both panel signalling to an app for each panel's parameter indication and inherent arc fault fire protection.
Hi David, apologies - I thought I had replied to your comment already, but I see it’s not there. You’re right - on the earlier video I bought into the general perception that shading on one panel would affect all the other panels in the same string. Upon receiving a few comments for that video talking about bypass diodes, I decided to do some research myself, which concluded in the later video. It’s not really possible to modify videos once published but you can place correction markers, which I did. They may not always be displayed though depending on the device/app being used to view the video. Thanks for the kind words regarding my videos - much appreciated 👍🏻 😀
Hi Jeff, the features you describe are more advanced and I didn’t want to overwhelm the audience with what is essentially an introductory video into Solar PV shading. I’m now making a follow-up video though and will incorporate some of these into that. Thanks 🙏
Great simple explaination thanks.
You’re most welcome 😀👍🏻
I have to say that was a great video I had no idea that the solar panels with micro inverters had those bypass diodes which makes them much more immune to shading problems .
Thanks Roger 👍🏻 I’ve got a follow-up video on shading coming very soon… Hope you enjoy that too!
Great video!👍
Thanks Jonas 😀👍🏻
Good job,
Good explanation
Thank you :-)
Great research, thanks for sharing.
You’re most welcome! 👍🏻😀
That was is a fantastic video. I have just been quoted for 3 strings, 4,4,6. One of the 4 will be shaded by a gable over time and they quoted optimisers for them. This makes sense no. I would imagine they will go from the simple aerial apology to the chimney over the day. This has given me more confidence in the company I have chosen. They have quoted them for a good reason and didn’t try and stitch me up by only adding them to the string that needs them. On to your next video now
Hi Michael, thanks for the kind words! :-) And really great that my video has been useful to you in making your decisions around solar. All the best with your solar journey!
Nice video, and well put together.
I'd add 1 more con to your list of optimizers
1. A constant 2% efficiency loss at the optimiser itself, regardless of shading or direct sunlight.
I feel that most PV systems do not require optimizers/micro Inverters, but they do have their place in more difficult roofs with unavoidable shading.
Good survey and design mitigates the need for optimizers in most cases in my opinion.
Thanks Euan, for the kind words and also the additional points. I’ll incorporate into my follow-up video on shading 👍🏻
Excellent, thanks.
You're very welcome. Thank you for taking the time to watch :-)
Brilliant, just brilliant.
Thanks Leon 😀
Great video.
We have optimizers and I am quite content with them. We have 92 panels on our apartment building. We have an east--west orientation with a raised edge around the flat roof and a chimney in the center. You can follow the output of each panel through an app and usually there are significant differences. If you have panels in different orientations, you have to make either separate strings, each with their own inverter or use optimizers/micro inverters. Micro inverters make sense if you don't have a large number of panels. It's not only about direct sunlight shading. In clouded weather (diffused light) all panels are affected differently by sources of shade and no cell will have 100% shading. Also, dirt on panels can reduce the output of some cells more than others. Long term if we have to replace some panels by non-identical ones, that will not give us any issues.
Agreed - having the ability to individually monitor a large array of panels is a great benefit to have! I'll cover some of the points you make here in a follow-up video I'm making, especially about non-identical panel replacement... thanks!
You forgot that you can make multiple strings with a main Inverter that support 1 ~ 4 string groups. Or use multiple smaller inverters (given that you have 92 panels) that each take 1 or 2 strings, and output in parallel.
The problem with micro inverters as i see it, they are exposed to potential hot temperatures, constantly with no cooling. That will affect them, despite the claimed 25 years warranty, vs a larger inverter that has active cooling to keep everything nice and cool. Take it from somebody in the IT business, there is a reason why datacenters have AC, and servers are stacked with loud fans. Electronics , and yes, that micro inverter has electronics in it, will degrade faster. And wait when one or more dies and you want or need to replace it. Its one thing on a apartment building with easy access but normal homes where you may need to remove a bunch of panels to access the issue panels.
@@benjiro8793 We have optimizers, which have less electronics in it than microinverters. Our rooftop has good accessibility for replacing broken optimizers. Multiple string groups requires more cables, which is significant, because the inverter is in the basement. We may not have the most economical solution, but I am content with it. Electricity production is above expectations.
That is the best presentation of the pros and cons of optimization that I have seen. Thanks! SMA says they have a new MPPT routine for their string inverter that works as good as optimizers in some circumstances without the reduced reliability. Have you figured that one out yet?
You’re most welcome, Mark. It’s great to get feedback like this, as my aim is simply to demystify everything. Now, I didn’t know about the new SMA MPPT routine - I’ll check that out… 👍🏻
Very helpful thank you.
You’re most welcome, John 👍🏻
Gary I send all my customers in 2 minds about shading to your video and encourage them to use your octopus referral code- thanks for your comprehensive research
Hi Aaron, that's so very kind of you to do that - thank you! I think some have signed up as well :-) You've very welcome regarding the video content. All the best!
Best Video so far! i found my problem! thank you
Thanks Nikolas :-) Glad to have helped you out
In addition to cons of optimizers (and microinverters) being cost and additional failure points, there is also lost efficiencies of having them in the system. For instance, the Tigo and Solar Edge optimizers are active devices which themselves consume power. So in a largely unshaded installation, the overall power output is typically greater without those parasitic device losses.
Hi Bill, a very good point. I'm hearing these devices use (lose) maybe 2% of the available power. I'd need to confirm that though...
Great really clear information. Excellent job!
Thanks Tony - it's great to get feedback like this :-)
There may be more to this than I first thought. I have just under 1/2 my panels shaded but I'm only now getting 1/4 of the expected output! Is there a multiplying effect of losses if you don't run optimisers?
What percentage of the day do your panels experience shading, and is it hard or diffuse shading?
@@GaryDoesSolar From mid day for approx 2 hrs. Its defused but towards the darker side as through a pine tree.I was surprised at the greater loss than the shaded panels. I counted even a partially shaded panel as fully off.
Thanks Tony. A few more questions if I may then:
1. How many panels?
2. what size each (kWp)?
3. what inverter?
4. On a clear sunny day what is the max generation power when not shaded?
5. On same day what is the generation power during shaded period?
Hi Gary, very informative video thanks. I'm just in the process of designing a system at home and wondering if I needed optimisers. I'm still not 100% sure, can you clarify what your diagram shows at 16:45. If I have 2 panels out of a string of 6 that are not producing any current, without optimisers are the other panels still able to push current through the shaded panels? I thought if all the panel was shaded it would block the current.
Hi Kieron, great to hear you got a lot from my video 😀 So, in the video then: if there were no bypass diodes in the panels, any fully-shaded cells would completely block current flow in that panel and also for all the other panels connected in the same string. The bypass diodes essentially “detect” shaded cells then re-route (bypass) current around them - to the extent where if a whole panel is shaded, the three bypass diodes in the panel will simply bypass the current through themselves, avoiding all the cells in the panel completely. Hope this helps!
Very informative video. Thanks for that tip. I have 3 different solar power systems that I own. 2 on the RV's and one on our house. the house has the Enphase micro inverters and the RV's both have NPPT controllers. Only one of the RV's uses an inverter. On the one RV I have seen a low or no output situation, as the solar panels had not been cleaned in quite a while. I thought it very odd that with 800 watts of possible output that the controller showed only the low battery voltage. I think it was around 8V, not enough to power the inverter or even the LED interior lights. Now I understand why that happened. I have a video about my 3 systems posted, if you'd like to check it out. I'd be very interested in your evaluation of my 3 different systems. I guess now I have to go clean a few solar panels!
Hiya - I'm going to take a look at your videos! :-)
This is a really nice overview of what the optimisers can and can't do. How often is shading extreme enough to actually trigger the bypass diode? Shaded but not bypassed seems to be where optimisers would work best. Even though they add cost they should reduce the fault finding time if a panel goes bad and can allow you to have different panel angles and positions without multiple string inverters.
Thanks Andy - great to get feedback like this.
Now, I read that bypass diodes will typically kick in when they detect a 20% difference in current. And I agree, if my roof had shading, I'd likely put in optimisers on the shaded panels just for the monitoring capability.
It is very rare for a panel to go bad. The probability calculation is not in favour of oprimisers. Even with untriggered bypass diodes, the optimisers gain only
@@GaryDoesSolar the bypass diodes are Schottky diodes, and they block the current in reverse, and conduct when the is a potential on 0.1 V accross them in the forward direction. @ 10A, they will dissipate 1W of heat. This is a failure point of cheaper panels that use cheap under sized diodes. A 3 or 5w rated diode should be used to ensure longevity. The diode is simply a one way valve.
From Wikipedia Schottky diode page:
"...
Reverse current and discharge protection
Because of a Schottky diode's low forward voltage drop, less energy is wasted as heat, making them the most efficient choice for applications sensitive to efficiency. For instance, they are used in stand-alone ("off-grid") photovoltaic (PV) systems to prevent batteries from discharging through the solar panels at night, called "blocking diodes". They are also used in grid-connected systems with multiple strings connected in parallel, in order to prevent reverse current flowing from adjacent strings through shaded strings if the "bypass diodes"
Effectively, if there is shading and the panel or string becomes effectively open circuit, the rest of the string, eg 300v, easily pushes past the 0.1v required turn on voltage of the diode, and current then flows past, bypassing the open string. Simple and effective.
In Australia it is possible to get Enphase micro-inverters at only 10% more than a string inverter. One of the most important benefits not listed here is the increased reliability and longevity of micro-inverters; our local supplier recently switched to offering only Enphase micro-inverters for that very reason.
There are also significant benefits for PV installation companies in terms of managing and storing stock.
Having inspected several houses and businesses with non functioning solar systems, I believe the improved monitoring from micro-inverters is well worth that extra investment.
Thanks Chris - good insight here 👍🏻 And great to here the pricing differential is lessening
@@GaryDoesSolar Enphase IQ8 microinverter has a 1/500000 failure rate and will function accordingly for 25 years, longer of course but that is the limit of the warranty, works when the grid is down without the need for a battery. The options focus on in this video will have to be replaced at least once, possibly twice during the life of the array. Those are undisputed facts and serious considerations. The solar industry is pushing for a module life span of 50 years, None of the tech featured is capable of such a feat. String will die a natural death, the future demands innovation. Ultimately customer service is the reason Enphase is number one in the USA and hyper-growing in Europe.
@@s.lionelmcauley4455 Thanks for this extra detail - you've given me an idea for a future video... 👍
Thank you for this video. Do you think on a house with quite a lot of shading from multiple trees (the whole moring and from 5pm) would be worth using optimizers? They will be south facing. And how much is marginally better as you said? Below 5% total extra or more like 20% for a shady situation like i have?
You’re most welcome, Roan. Ok, so without knowing your particular shading scenarios, I can’t determine what improvement you might get. Certainly, for free shading, optimisers will help, and the Tigo products are relatively cheap to buy and fit. Have a chat with a few installers (to get a reasonably unbiased view) and good luck with whatever you decide.
Great video once again Gary. One question, I have read that wiring in parallel rather than series also has an effect on shading, i.e wiring in parallel limits power loss similar to optimisers, have you an opinion on this?
Thanks for the kind words! Yeah, I did start to look into that, and decided that it would be too much to put in such an introductory video, and nearly all domestic installs are series only in any case. I don't have any particular view other than parallelism allows the current more flow options, in a similar way to the bypassing that the diodes provide.
@@GaryDoesSolar I believe that some inverters have 2 sets of connections for PV arrays, assume this is probably for 2 completely seperate arrays ie east and west, however I suppose if you have 1 large roof you could split the array electrically into 2 ? and have these connecting to the 2 PV array connections ?
Another awesome video Gary.👍👍. The only benefit as far as I can see is the ability to check how each panel is working. Might be useful for the photon geeks?
Have you seen the Australian CZcamsr: Off Grid Garage he demonstrates Hyundai shingled panels with a voltmeter and fries his voltmeter entitled "Hyundai Shingled Solar Panels - 15% better than other solar panels?"
Thanks David. Very kind of you to say 😀 You’ve got me thinking about these shingled panels…. 👍🏻
Very well done, Thx!
How big is the power consumption (loss) of the micro inverters?
Couldn't find anything in the Tigo datasheet?
That’s a good question! I don’t know the answer - it would have to be low however, otherwise it would negate any production increase 😳
Gary, thanks for the informative video. I am just a bit unsure about my situation. I want to extend a PV string composed of 410W panels, but due to lack of space on the South side of the roof I would like to put extra panels (400W) on the West/East side. Does it make sense to put optimizers on all panels? My thought was that I just need to put optimizers on the extra panels, on the West/East side. What do you think?
Hi Mihai, you're most welcome - thanks for taking the time to comment :-)
Now, for the new panels on the East/West side, there are a number of considerations, and you're best to speak to your installer about the options.
For example, it may not be possible to add further panels to your existing string inverter (they have a maximum voltage per string). So, this would mean a second inverter. It would have two string inputs so you could split East and West without requiring any optimisers.
Another option is to remove your existing inverter and install microinverters to all your existing and new panels. That might be a more costly option though.
Whatever you decide, all the best!
Great video 👍
Thank you Wayne 😀👍🏻
I have a question you may be able to help me with.
I currently have a grid tied 8 x 370W panel and 3.6Kw Solis inverter system and want to add an additional 6 x 370W panels on a different elevation and string. Will this effect the efficiency of my current panels?
Will connecting the 2 strings using a diode connection fix any issues?
Hi Wayne, unfortunately, I'm not in a position to provide advice (not least because of potential liability issues - even if advice is given free - such is the world today). You're best to speak to an installer about that, or post a comment onto a solar forum (e.g. this one in the UK: facebook.com/groups/2197329430289466) Good luck!