Prices have dropped like a stone, especially on batteries. Just over 2 years ago I paid £11k for 12x 400w panels on one roof, 5kW inverter and 7.5kWh of batteries!
You'd have been talking £20k+ for what Imfy2k has been quoted back then!
Solar panels and battery - any real world recommendations?
- Thread starter GinG
- Start date
You'd have been talking £20k+ for what Imfy2k has been quoted back then!
i know right
mines' 10x 440w + 3.6kw inverter + 10kw battery for £8.3k
Imfy is more than double that for only 1.5x the cost!
thanks, awaiting ther DNO approval for export first, i wonder what it will be!
I've knocked up a design for my new roof and tried to work out where I could fit panels. I've left ~400mm to the roof edges, but most of these roofs are new so I'll likely be going for in-roof panels, which hopefully means I can go closer to the edges (so I might be able to squeeze a few more on).
As you can see, there's a lot of different orientations/layouts involved, so I don't thing s classic string inverter is an option. I want to pair these with batteries, so I believe my options are (and correct me if I'm wrong) to go for a hybrid inverter, or optimisers on each panel. The latter bumps up the cost considerably, but the former I believe means I'm restricted to a max 3 strings as the max number of MPPT's on hybrid inverters seems to be 3.
If that's true, which 3 strings would you pick from the following options? The blue wall is North facing, the yellow wall is South facing.
I was thinking 1 string for the east facing main roof (14 panels if I can include the 2 on the extension in the string), 1 string for the south facing main roof (6 panels), and then it's a toss up between 7 panels on the East facing lower roof, vs 6 panels on the North facing main roof. The former would get more direct sunlight, but would be shaded by the house for half of the day. It might not be too aesthetically pleasing either.
Any comments/suggestions?
As you can see, there's a lot of different orientations/layouts involved, so I don't thing s classic string inverter is an option. I want to pair these with batteries, so I believe my options are (and correct me if I'm wrong) to go for a hybrid inverter, or optimisers on each panel. The latter bumps up the cost considerably, but the former I believe means I'm restricted to a max 3 strings as the max number of MPPT's on hybrid inverters seems to be 3.
If that's true, which 3 strings would you pick from the following options? The blue wall is North facing, the yellow wall is South facing.
I was thinking 1 string for the east facing main roof (14 panels if I can include the 2 on the extension in the string), 1 string for the south facing main roof (6 panels), and then it's a toss up between 7 panels on the East facing lower roof, vs 6 panels on the North facing main roof. The former would get more direct sunlight, but would be shaded by the house for half of the day. It might not be too aesthetically pleasing either.
Any comments/suggestions?
I have an East-West split like your main house, together with a dormer. I think there are some hybrids with more than 3 MPPTs FWIW, but I think get all those East panels on one string on both the upper and lower. On a sunny day in winter, my East array of 8 panels still generates around 1.2kW until lunchtime. The West array doesn't come in until lunchtime and gets quite a bit of shading from the dormer. I would suggest definitely doing the East array over the North one if you have to choose. If you can do both then why not; the North array will probably get very little direct sun outside of summer but they still do a bit even shaded. On the East array you might end up having to split the string because of the voltage - 21 panels is more than mine could handle on one string.
The upcoming GivEnergy hybrid all in one has 6 MPPTs IIRC. That’s if you want a plug and play solution.
Personally I would remove the random single panels. You should also expect your house roof to shade the south panels in winter so you may want some optimisers anyway or accept they’ll be sub optimal.
I would prioritise, east, south, north and west in that order. North is going to generate more than west as you have 50% more panels.
The slightly lower roofs on the east/west may also get some shading in winter from your main roof.
Personally I would remove the random single panels. You should also expect your house roof to shade the south panels in winter so you may want some optimisers anyway or accept they’ll be sub optimal.
I would prioritise, east, south, north and west in that order. North is going to generate more than west as you have 50% more panels.
The slightly lower roofs on the east/west may also get some shading in winter from your main roof.
Have you use something like PVGIS to see what your expected generation will be depending on the orientation
re.jrc.ec.europa.eu
JRC Photovoltaic Geographical Information System (PVGIS) - European Commission
Photovoltaic Geographical Information System (PVGIS)
Any panels on the same pitch and orientation can be combined into a single string, up to the limits of the MPPT, do be mindful of shading.
Panels on different pitch and/or orientation really need to be on another string, one way around this is to run strings in parallel, parallel strings need to be the same panels and same quantity, but one strings output won't really affect another in a parallel configuration.
It all gets quite complicated as you have to be careful of the maximum voltage and current that the strings generate, and take into account the voltage at the coldest temperature, as it will be higher. Voltage drop is also a consideration.
Are you diying it, or getting an installer to do it?
Panels on different pitch and/or orientation really need to be on another string, one way around this is to run strings in parallel, parallel strings need to be the same panels and same quantity, but one strings output won't really affect another in a parallel configuration.
It all gets quite complicated as you have to be careful of the maximum voltage and current that the strings generate, and take into account the voltage at the coldest temperature, as it will be higher. Voltage drop is also a consideration.
Are you diying it, or getting an installer to do it?
Even on the East facing roofs with some on the main roof and some on the lower roof? I would've thought the lower roof would need to be on a separate string as it would be in complete shade in the afternoon, whereas the main roof would still be getting some light.
Installer, but I want to have a good idea about what's going to be done so the builders can quote for the right amount of roofing work (i.e reduced tile count).
No I haven't. That's great, thanks.Have you use something like PVGIS to see what your expected generation will be depending on the orientation
JRC Photovoltaic Geographical Information System (PVGIS) - European Commission
Photovoltaic Geographical Information System (PVGIS)
If it were me, I'd just cover all the space with panels, even if you don't connect some initially as it'll be cheaper than tiles, and your roof will be more 'even' looking. If designed correctly you could also fit inverters/micro inverters in the loft space making a combined system possible. The Fox KH10 has 4x MPPT inputs as well as offering 10kW of output, only 75v start up and is costs well under £1k.
If there is going to be substantial shading then two strings would be better, hence I said be mindful of shading.
There is multiple ways to do it, but each installer has their preferred system and opinions, some like to fit micro inverters on every panels, and these could work well in situations like your's, others may fit more than one inverter, others will just want to fit a basic system, others will go SolarEdge with optimisers, but you may still need more than one string, optimisers are not a magic fix, and have limitations.
My system has two inverters, and the Victron system has multiple MPPT's attached on the DC side along with the batteries, but that has limitation on maximum string voltage, lower voltage means higher currents, means more voltage loss on cables etc.
It's probably best to engage with some installers, and see what they come up with, hopefully you'll find one that's flexible.
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I was only able to get a single quote 2-3 years ago after contacting maybe 8-10+ companies.
The quote I got could only fit 5 panels and I wanted some wall-mounted ones in addition to make it worth while but no one was able to or interested in installing the. That quote for 5 panel on the roof was over £7k with no battery so a pass. I knocked it on the head after that.
Contacted a few places recently and more companies now seem to be doing the wall installations. So when installed at the back of the house should look similar to a short awning so not a total eye-sore.
As prices have dropped a bit I'm curious to know current prices so am arranging a few quotes. Maybe I'll get something suitable this time round!
The quote I got could only fit 5 panels and I wanted some wall-mounted ones in addition to make it worth while but no one was able to or interested in installing the. That quote for 5 panel on the roof was over £7k with no battery so a pass. I knocked it on the head after that.
Contacted a few places recently and more companies now seem to be doing the wall installations. So when installed at the back of the house should look similar to a short awning so not a total eye-sore.
As prices have dropped a bit I'm curious to know current prices so am arranging a few quotes. Maybe I'll get something suitable this time round!
I just posted in the solar production thread an was redirected here.
I had a quote from Heatable who are the only company to come back to me so far but the quote was so expensive I couldn't see any benefit in it. For info we use between 30-40kw of electric a day in the winter and just slightly less in the summer. We also have a hot tub so the demand on our electric can occasionally go up to 11-13kw with the polestar plugged in and ovens on.
Heatable came back with a a quote of £25K for 30 panels on our south facing roof, tesla Powerwall 3 and extra battery (chose the Powerwall due to the inverter being rated so high), including scafolding and fitment. Obviously this put me off but seeing this thread it seesm we could get a much better price on a similar system.
I was also looking at the Sigenergy batteries although the tesla cells seem like they woud be less obtrusive on the outside wall. Any recomendations for an installed near Heathrow/West London?
I had a quote from Heatable who are the only company to come back to me so far but the quote was so expensive I couldn't see any benefit in it. For info we use between 30-40kw of electric a day in the winter and just slightly less in the summer. We also have a hot tub so the demand on our electric can occasionally go up to 11-13kw with the polestar plugged in and ovens on.
Heatable came back with a a quote of £25K for 30 panels on our south facing roof, tesla Powerwall 3 and extra battery (chose the Powerwall due to the inverter being rated so high), including scafolding and fitment. Obviously this put me off but seeing this thread it seesm we could get a much better price on a similar system.
I was also looking at the Sigenergy batteries although the tesla cells seem like they woud be less obtrusive on the outside wall. Any recomendations for an installed near Heathrow/West London?
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That's just the sort of quote I expect from Heatable, I wouldn't be surprised if they quoted for bifacial panels and enphase micro inverters, the former is of no benefit when used on a roof, the latter often not required.
I was going to ask if it was Ashford Kent, but I see it's not.
Yep Rea BiFacial panels. There is a 20m cable run to the garage at £650 and £1k in scaffolding in the quote, no micro inverters though.
Looking at the roof proposal I could likely get another 8 panels on the roof taking it to 38.
More panels the better, but you don't need expensive bifacials on a roof, surprised they didn't include micro inverters, but it would be madness unless you had shading issues or wanted the extra safety factors, but that's what Heatable usually seem to do.
With solar panels you buildup your credit through the summer with exports, I always charge my batteries fully, even in the summer as its 7p kWh, and exports are 15p. That credit then takes me through the winter months, admittedly my usage isn't as high though.
With solar panels you buildup your credit through the summer with exports, I always charge my batteries fully, even in the summer as its 7p kWh, and exports are 15p. That credit then takes me through the winter months, admittedly my usage isn't as high though.
As above, I also charge daily at 7p 365 days a year.
Don’t forget, with an EV and an EV tariff you only need batteries to cover 18 hours a day and none of your EV demand. Also with that much south facing solar, you will not need shed loads of battery capacity to get though a terrible winters day’s generation.
You get diminishing returns on batteries quite quickly once you get past what actually need, they are only cost effective if you use them. You can play the import at 7p and export at 15p game but it doesn’t really pay back when you are paying retail for batteries, particularly high end (expensive) units like the power wall and for someone to install it.
Do you need that 20m run to the garage? You can have them outside on the side of the house if it’s easier, it will be cheaper.
The other thing you might hit up against is export limits, you’ll be lucky to get 10kw, you might only get 3.6kw.
Do you have 3 phase? You are also pushing up against the realistic limits of what you can have on single phase supply. 30 450w panels is 13.5kw, that will play nice with a 10kw single phase inverter. 38 panels is pushing 17kw and will probably not.
But yes, get some more quotes because that first one is just silly.
Don’t forget, with an EV and an EV tariff you only need batteries to cover 18 hours a day and none of your EV demand. Also with that much south facing solar, you will not need shed loads of battery capacity to get though a terrible winters day’s generation.
You get diminishing returns on batteries quite quickly once you get past what actually need, they are only cost effective if you use them. You can play the import at 7p and export at 15p game but it doesn’t really pay back when you are paying retail for batteries, particularly high end (expensive) units like the power wall and for someone to install it.
Do you need that 20m run to the garage? You can have them outside on the side of the house if it’s easier, it will be cheaper.
The other thing you might hit up against is export limits, you’ll be lucky to get 10kw, you might only get 3.6kw.
Do you have 3 phase? You are also pushing up against the realistic limits of what you can have on single phase supply. 30 450w panels is 13.5kw, that will play nice with a 10kw single phase inverter. 38 panels is pushing 17kw and will probably not.
But yes, get some more quotes because that first one is just silly.
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I'm running 30 x Seraphim S4 N-Topcon Series Bifacial 440W Black Frame 108 Half-Cut Cells(SRP-440-BTD-BG (IEC 61215-2021))
This was a google image of were they planned to place the 30 panels.
Working well for us in the Queensland sunshine. Ergon, our energy company down under is currently paying us $100 per month
This was a google image of were they planned to place the 30 panels.
Working well for us in the Queensland sunshine. Ergon, our energy company down under is currently paying us $100 per month
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I’d Get more quotes if I was you, the more the better. I’ve Sent you the name of my installer.
I'd check out Octopus and Ovo Energy. I went with Ovo over my local installers because I wanted a company that I knew would be around, and because they offered a 0% 3 year financing deal.