MrTWales Posted June 13, 2023 Share Posted June 13, 2023 I have 12 panels on a flat roof and no massive issues with shading, but for some times of the year the start and end of the day are impacted with the lower sun. The 12 panels are one single series so I was thinking about splitting into two 6-panel series, which may not actually cost any more as it's so simple (the installers are back today fitting an immersion heater and seem to be willing to do this as part of the install, but any extra cost would be small anyway). In theory optimisers would be better (?), though in my case the extra value would be pretty small. Given the extra cost would be a lot am I correct in thinking that it's just not worth it? I honstly didn't realise how much they cost until I did a quick search today. Thanks! Link to comment Share on other sites More sharing options...
SteamyTea Posted June 13, 2023 Share Posted June 13, 2023 7 minutes ago, MrTWales said: but for some times of the year the start and end of the day are impacted with the lower sun. Not much power in a low sun, especially if your modules are at around 30⁰. You may find optimisers increase overall output by 2% of very little. 1 Link to comment Share on other sites More sharing options...
MrTWales Posted June 13, 2023 Author Share Posted June 13, 2023 Thanks. At this time of year with the high sun it barely makes any difference but at others I can see times when most panels are getting sun (so maybe I'd get 2kW with no shade) but it's held back by a couple being in shade. Any value placed on this is likely small as you say, but it is fecking annoying at times when I use 100% of what the panels generate. It sounds like just splitting into two lots of 6 panels may be the best option, esp as it seems like no cost against 12 lots of £60 or something like that. The subcontractor seems like he is happy to do this today without any mention of extra cost anyway! Link to comment Share on other sites More sharing options...
JohnMo Posted June 13, 2023 Share Posted June 13, 2023 I am in a similar position, have just bought 12 panels, I will be splitting into 2x6 arrays. I did concider optimiser, and rejected them, due little or no shade except clouds. I do have them on my roof array, but that gets a fair bit of shading. 1 Link to comment Share on other sites More sharing options...
MrTWales Posted June 13, 2023 Author Share Posted June 13, 2023 1 hour ago, JohnMo said: I am in a similar position, have just bought 12 panels, I will be splitting into 2x6 arrays. I did concider optimiser, and rejected them, due little or no shade except clouds. I do have them on my roof array, but that gets a fair bit of shading. Thanks - I kinda of thought this but knew I'd get instant confirmation (or otherwise) on this forum so just wanted to check that I wasn't missing a trick. To be honest, I didn't realise how much optimisers cost until today. It seems like the splitting into two is very quick and easy, though this is partially as there is no skafolding invoved in my case I guess. Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 13, 2023 Share Posted June 13, 2023 2 hours ago, MrTWales said: I have 12 panels on a flat roof and no massive issues with shading, but for some times of the year the start and end of the day are impacted with the lower sun. The 12 panels are one single series so I was thinking about splitting into two 6-panel series, which may not actually cost any more as it's so simple (the installers are back today fitting an immersion heater and seem to be willing to do this as part of the install, but any extra cost would be small anyway). In theory optimisers would be better (?), though in my case the extra value would be pretty small. Given the extra cost would be a lot am I correct in thinking that it's just not worth it? I honstly didn't realise how much they cost until I did a quick search today. Thanks! You can buy a dual Tigo which does 2 panels with one device. 1 Link to comment Share on other sites More sharing options...
Dillsue Posted June 13, 2023 Share Posted June 13, 2023 2 hours ago, MrTWales said: Any value placed on this is likely small as you say, but it is fecking annoying at times when I use 100% of what the panels generate. Only you know the value of optimisers as only you know the annoyance of not generating at max. For pure ROI it can vary massively. If you buy at retail prices and pay someone to fit them you may never get your money back if shading is only causing a small loss. On the other hand if youre not in a rush and wait for optimisers to come up on ebay you can buy them at a fraction of the retail price. If you fit them yourself, which is straight forward, then you make more of a saving. Optimisers give you individual panel monitoring so you can see at a glance if and where youve got a problem. I've just moved 4 panels that had partial shading but it was only the individual monitoring that showed how much they were being impacted by a nearby chimney How to quantify "shading" losses is near impossible to determine as shading comes in so many forms- trees, structures, algal growth, dust, clouds, bird s**t etc. Picking them up off eBay and self installing makes it worth while for me, but that might not be the case for you, only you know how you value things! 3 Link to comment Share on other sites More sharing options...
MrTWales Posted June 13, 2023 Author Share Posted June 13, 2023 36 minutes ago, Dillsue said: Only you know the value of optimisers as only you know the annoyance of not generating at max. For pure ROI it can vary massively. If you buy at retail prices and pay someone to fit them you may never get your money back if shading is only causing a small loss. On the other hand if youre not in a rush and wait for optimisers to come up on ebay you can buy them at a fraction of the retail price. If you fit them yourself, which is straight forward, then you make more of a saving. Optimisers give you individual panel monitoring so you can see at a glance if and where youve got a problem. I've just moved 4 panels that had partial shading but it was only the individual monitoring that showed how much they were being impacted by a nearby chimney How to quantify "shading" losses is near impossible to determine as shading comes in so many forms- trees, structures, algal growth, dust, clouds, bird s**t etc. Picking them up off eBay and self installing makes it worth while for me, but that might not be the case for you, only you know how you value things! Ah, so you don't need to do anything clever with inverter setting etc or to use on all panels? I guess if it's something that can be done over time, individually, it may be more viable I guess but at least I get the instant win with the two series and this wouldn't hurt even with optimisers. It's a low flat roof but I'd still be wary of fitting myself unless it was very very easy and safe! Link to comment Share on other sites More sharing options...
Dave Jones Posted June 13, 2023 Share Posted June 13, 2023 i use enphase micro inverters for this reason. bit more expensive but a doddle to fit. Link to comment Share on other sites More sharing options...
billt Posted June 13, 2023 Share Posted June 13, 2023 As others have said, it's highly unlikely to be worth while in terms of energy saved. There are optimisers on 32 of our 54 panels. Most don't do much, one set does. One string of 6 panels facing SE has shading on the bottom 3 panels from trees in the morning. I put optimsers on those panels and there is virtually no reclaimed energy Garage has 12 panels on one side with optimisers on 9 panels and shading in the morning and also doesn't recover much energy. The other side of the garage roof has more significant shading and optimisers on every panel. That recovers more energy, but it's not an amazing amount. There are also 8 panels on a shed which face 3 different directions and have significant shading throughout the day. These do recover a noticeable amount of energy. Conclusion, it isn't worth it financially, but for me it is for the monitoring. 2 Link to comment Share on other sites More sharing options...
SteamyTea Posted June 13, 2023 Share Posted June 13, 2023 10 minutes ago, billt said: Conclusion, it isn't worth it financially, but for me it is for the monitoring Was it really worth fitting modules on the shed. Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 13, 2023 Share Posted June 13, 2023 41 minutes ago, billt said: Conclusion, it isn't worth it financially, but for me it is for the monitoring. Yup. I'll end up with a few fragmented arrays feeding into 2 strings, so I will defo be going wither 2 panels 1 Tigo, or if I can get a trade deal 1 for 1. I don't have much tech in my life tbh, so this will "please me", and I am happy to pay for that, regardless. Prob add less than a grand all up, including monitoring. Less if I can go dual. Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 13, 2023 Share Posted June 13, 2023 31 minutes ago, SteamyTea said: Was it really worth fitting modules on the shed. We do these things because we can. Link to comment Share on other sites More sharing options...
MrTWales Posted June 13, 2023 Author Share Posted June 13, 2023 (edited) Holy smokes that's a lot of solar. A generation chart from earlier this months shows that there aren't really any major shade issues at this time of year, but there are some sharper peaks in winter months at either end. I'm happy with the two series set up now, as it was zero extra cost! Edited June 13, 2023 by MrTWales Link to comment Share on other sites More sharing options...
billt Posted June 13, 2023 Share Posted June 13, 2023 1 hour ago, SteamyTea said: Was it really worth fitting modules on the shed. Yes; the panels were left over from our last house so they didn't cost anything. I've still got 8 doing nothing. Link to comment Share on other sites More sharing options...
SteamyTea Posted June 13, 2023 Share Posted June 13, 2023 24 minutes ago, billt said: I've still got 8 doing nothing Flog them. Link to comment Share on other sites More sharing options...
TonyT Posted June 13, 2023 Share Posted June 13, 2023 Can the inverter handle the reduced start up voltage if you split the existing circuit into 2? Link to comment Share on other sites More sharing options...
JohnMo Posted June 13, 2023 Share Posted June 13, 2023 56 minutes ago, TonyT said: Can the inverter handle the reduced start up voltage if you split the existing circuit into 2? You need an inverter designed for the task, so take two independent arrays. So is basically two inverters (2 x DC inputs) with a single AC output. Link to comment Share on other sites More sharing options...
MrTWales Posted June 13, 2023 Author Share Posted June 13, 2023 1 hour ago, TonyT said: Can the inverter handle the reduced start up voltage if you split the existing circuit into 2? The inverter has been telling me for months to set PV2 so it's been expecting it! In terms of the size, maybe it's an issue sometimes but the inverter in my case is probably bigger than it needs to be as parts were so hard to get the installer used this but priced on a smaller one. It seems to be working so far anyway, unlike the immersion diverter. Sigh. Link to comment Share on other sites More sharing options...
TonyT Posted June 13, 2023 Share Posted June 13, 2023 2 hours ago, JohnMo said: You need an inverter designed for the task, so take two independent arrays. So is basically two inverters (2 x DC inputs) with a single AC output. I know I was asking MrT Wales Link to comment Share on other sites More sharing options...
JohnMo Posted June 13, 2023 Share Posted June 13, 2023 4 minutes ago, TonyT said: I know I was asking MrT Wales Sorry Link to comment Share on other sites More sharing options...
TonyT Posted June 13, 2023 Share Posted June 13, 2023 No worries👍 Link to comment Share on other sites More sharing options...
Dillsue Posted June 13, 2023 Share Posted June 13, 2023 4 hours ago, MrTWales said: The inverter has been telling me for months to set PV2 so it's been expecting it! In terms of the size, maybe it's an issue sometimes but the inverter in my case is probably bigger than it needs to be as parts were so hard to get the installer used this but priced on a smaller one. It seems to be working so far anyway, unlike the immersion diverter. Sigh. Worth checking the spec of the inverter to see what the minimum start voltage is for each MPPT input. By splitting the array in half youre likely halving the voltage on the input so just check your 6 panels are going to give a high enough start voltage. Link to comment Share on other sites More sharing options...
MrTWales Posted June 14, 2023 Author Share Posted June 14, 2023 I looked at the inverter label (LXP-6K Hybrid) and can't see this, but it's working well so far and it seemed to give slightly higher input at the start of the day when there wasn't much coming in and probably shade on only some of the panels. Link to comment Share on other sites More sharing options...
PhilT Posted June 14, 2023 Share Posted June 14, 2023 (edited) Was it worthwhile getting optimisers? Not sure. In this photo, taken yesterday late afternoon, the left panels where the vertical shade line is have dropped from 320W to 40W. Am I right in thinking that all 8 panels would fall to 40W without optimisers? If so, from the data playback function I worked out that this would have been worth c. 4kWh yesterday. Edited June 14, 2023 by PhilT Link to comment Share on other sites More sharing options...
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