Solar panels and battery - any real world recommendations?

Others may disagree but £10k seems quite expensive for a 3.6kw array and 8kwh battery, does that include a gateway?

Yes, sigen is getting a lot of praise at the minute but is it £10k good? Not sure.

Can you only fit 8 panels on your roof?
 
Others may disagree but £10k seems quite expensive for a 3.6kw array and 8kwh battery, does that include a gateway?

Yes, sigen is getting a lot of praise at the minute but is it £10k good? Not sure.

Can you only fit 8 panels on your roof?
Our first quote and new to the scene, so no reference point but good to know from others (we are in SW London if that helps). It's 4 panels on our garage and 4 on our kitchen extension roof. We left out the house roof as we may do a loft extension/conversion in the next 5 years so thought we'd add more then. It doesn't include a gateway.
 
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It’s probably fair to say there is a certain amount of ‘this is a pain in the but install’ premium going on there.

The other option is to install on the house roof also, remove and reinstall when the time comes for the conversion. You’d benefit from the solar in the mean time and the cost of removing the panels and reinstalling them when doing a loft conversion is trivial. 5 years is a very long time.

Unless MCS have updated their saving projection methodology, I’m also not sure how they managed to come out with a 6 year pack back on a £10k install that only produces 2600kwh/year. I make that 7.5 years based on the cost and projected saving.
 
Thank you. So let's say we could get another 3 panels on the roof*, that would be another 37% in production capacity. I think that would be 3,600 kWh of generation or about £1,700 of savings pa.

*Doesn't look a great deal of space on our roof, might get my drone out for better pics and chuck it into whatever software can work out the size (according to Google).

Edit - perhaps get a 10k kWh Sigenergy battery and add a 6k kWh battery) module further down the line?

Edit - next quote with newer generation panels and batteries.

 
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I have just been quoted £7200 for the following system fully fitted, just looking for some guidance is it’s in the ballpark for what I should be paying
Solar Panels
Aiko Energy
4.7 kW Total Module Power
10 x 465 Watt Panels
Inverter
Sunsynk 3.6kW ECCO Hybrid Inverter
Battery
Sunsynk W-Series 5.32kWh Battery
 
Can anyone advise on a rough ballpark for how much I need to set aside over the next few months for a PV + battery system?

We use about 50-60kW/day, up to 100kW on car charging days. Car charging happens on the cheap Octopus night rate so not too worried about that. I reckon I should get at least 50kW of battery storage, probably closer to 65ish to be on the safe side. I'll pull my Octopus data from the last 12 months to work out the exact number that >95% of days or whatever would be fully covered.

I've got a big roof so can slap on loads of panels that's not an issue.

I've only got single phase power though so presumably that'll need upgrading to three phase?

Will be getting a bit over £20k from selling a car which I'm thinking of putting aside towards this budget, but wondering how much more it'll need topping up. And whether it's worth doing this year winter or waiting for longer if the PV/battery tech looks like it's going to get better/cheaper in future.
 
You won’t need 65kwh of battery storage, not even close. You’ll probably not be able to charge that much on a single phase supply during off peak hours anyway.

The thing that people miss about battery storage is that once you have ‘enough’, the return on investment tanks and can even be negative if you are paying retail prices for a premium system.

On the other hand solar panels scale almost linearly at the moment with current prices and export rates. The marginal cost of adding more solar is very small.

For example, the cost difference between 20 panels and 22 panels is probably in the region of £300 where as batteries you need to buy in 5-10kwh chunks and each chunk costs £2-4K depending on size.

The more important question is how are you using so much energy? Do you have a hot tub/sauna/swimming pool? What is your heating system and how much does that consume compared to the rest of the house?
 
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I reckon I should get at least 50kW of battery storage, probably closer to 65ish to be on the safe side.

Cheapest option if doing that is two of THESE connect to a compatible inverter, 80% DoD, and if you are going 3-phase (that'll set you back anywhere up to £10k+) you'll have no problem charging them off-peak.
Lots of inverter choice to match as well if you want to chose something that suits your use case, some people prefer a onebox/one manufacturer solution if they can't/don't want to teach themselves a few things about the kit they are buying, but from a battery point't of view it'll be 3-6x the cost per kWh.
 
Hi all I'm very new to the solar install space but we've got a 1960s property with a dormer on the south facing roof. We had someone come out the other day for an initial quote as we're putting in a planning application for a small extension and thought we'd like to include solar panels in it as we're in a conversation area. My wife spoke with the local chap who came around so I don't know if this is the maximum he could fit but I'm assuming so.

9 x Aiko Energy 475 Watt Panels (AIKO-A475-MAH54Mw) 8 main roof + 1 Extension roof
1 x H1-5.0-E (Fox ESS)
1 x EP11 Integrated with Warming Function (Fox ESS)

4.275 kW System Size
£979 Estimated Annual Electricity Bill Savings
£8,034 Total System Price
7 years 8 months payback time

I don't know if the price is reasonable/good/bad and will obviously get more quotes. I'm just worried about the system capacity i.e. only having 8-9 panels. Would it make sense to ask for a quote with them adding panels to the dormer if possible or maybe on the north side of the roof although I'm not sure if that makes sense due to limited sun exposure and payback time impact?
 
You won’t need 65kwh of battery storage, not even close. You’ll probably not be able to charge that much on a single phase supply during off peak hours anyway.

The thing that people miss about battery storage is that once you have ‘enough’, the return on investment tanks and can even be negative if you are paying retail prices for a premium system.

Could you explain this a bit more? If i use e.g. 60kW in a day, if I've got that much stored in my batteries from overnight it'll all be at the cheap rate so a huge saving no? And as you say I'd probably need to get three phase as well to be able to charge that much overnight.

The more important question is how are you using so much energy? Do you have a hot tub/sauna/swimming pool? What is your heating system and how much does that consume compared to the rest of the house?

Heating system is gas boiler, with a bunch of pumps and storage tanks and things. Swimming pool is also heated via gas boiler as the ASHP has a fault that I don't want to spend £1000 to fix. Sauna doesn't get used much. The pump/plant room for the house's heating and hot water uses about 0.6kWh 24/7.

Cheapest option if doing that is two of THESE connect to a compatible inverter, 80% DoD, and if you are going 3-phase (that'll set you back anywhere up to £10k+) you'll have no problem charging them off-peak.
Lots of inverter choice to match as well if you want to chose something that suits your use case, some people prefer a onebox/one manufacturer solution if they can't/don't want to teach themselves a few things about the kit they are buying, but from a battery point't of view it'll be 3-6x the cost per kWh.
That seems dirt cheap for the amount of battery! I've heard it's difficult to find an installer for these Fogstar batteries though?
 
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Could you explain this a bit more? If i use e.g. 60kW in a day, if I've got that much stored in my batteries from overnight it'll all be at the cheap rate so a huge saving no? And as you say I'd probably need to get three phase as well to be able to charge that much overnight.



Heating system is gas boiler, with a bunch of pumps and storage tanks and things. Swimming pool is also heated via gas boiler as the ASHP has a fault that I don't want to spend £1000 to fix. Sauna doesn't get used much. The pump/plant room for the house's heating and hot water uses about 0.6kWh 24/7.
Ah yes, I remember now, just lots of stuff.

As for not needing 60 kWh of batteries, you need to factor in that a chunk of your consumption will be in the off peak period so you don’t need any battery storage to cover that consumption.

Then also consider any other loads that you can confine to the off peak period like hot water, dishwashers, washing machines, dryers etc.

Then you can factor in you having a large roof, you’ll be generating a material amount of electricity for 9 months of the year and a non-zero amount over winter.

In summer your batteries are only covering a few hour gap when the solar isn’t generating and the off peak period. The benefit they are adding is negligible.

The goal isn’t zero peak take electricity, it’s lowest cost. You need to factor in the cost of the batteries and the benefit they’ll bring.

As mentioned above, you can only buy them in chunks. Say you needed 42kwh of batteries to cover your day time use but you can only buy them in 10kwh chunks for that system. Spending £3k on a 10kwh battery to cover 2kwh of usage will cost you more money than it saves over its expected useful life (say 15 years). You’d be better off just drawing from the grid.

TLDR, the more solar panels you have, the less batteries you need. Savings from the panels scale linearly with size, the opposite is the case with batteries, the benefits go down the bigger you go.

That seems dirt cheap for the amount of battery! I've heard it's difficult to find an installer for these Fogstar batteries though?
installers won’t touch fogstar, the best you’ll get is the they’ll install a hybrid inverter with no batteries but they’ll wash their hands of it if you want to DIY the batteries so you’ll probably get no support and zero warranty because you’ve materially altered the system.

Installers have generally have enough work that they don’t need to engage with semi-DIYers and they’d prefer to supply the whole system because they can apply their mark up on the parts and make more profit.
 
You won’t need 65kwh of battery storage, not even close. You’ll probably not be able to charge that much on a single phase supply during off peak hours anyway
With my 8kW inverter I could charge 48kWh in the 6 hour off peak window. Go 12kW and in theory that's 72kWh.

Of course you have to be mindful of total grid draw, using a 12kW charger doesn't give much leeway for other loads.
 
@Minato do it as soon as possible, solar is like computer parts, always evolving.

As @b0rn2sk8 says you won't need 65kWh of storage, on Octopus Go you only need to cover 5;30 to 23:30.

I also think you'd need 3 phase, for reasons in the post above, look at Sigenergy, easily expandable if you find you need to add more battery capacity, and fit as many panels as possible.

@n30_mkii fit as many panels as possible, even on north facing roofs. It bumps up winter production a bit, but really boosts summer generation which currently can be banked at a reasonable rate for winter.
 
@Minato do it as soon as possible, solar is like computer parts, always evolving.

As @b0rn2sk8 says you won't need 65kWh of storage, on Octopus Go you only need to cover 5;30 to 23:30.

I also think you'd need 3 phase, for reasons in the post above, look at Sigenergy, easily expandable if you find you need to add more battery capacity, and fit as many panels as possible.

@n30_mkii fit as many panels as possible, even on north facing roofs. It bumps up winter production a bit, but really boosts summer generation which currently can be banked at a reasonable rate for winter.
Thanks, I think my wife asked about north facing side and the advise from the installer was he'd only recommend doing it if replacing the roof as it can be installed at the same cost or less as the tiles or something along those lines. Is there any good guidance on using north facing to optimise?
 
Most installers won't install north facing panels, they are rather out of date with their thinking. My own 5.2kWp west north west array has generated 3.475 MWh since installation last October.

This is a care home built in our area recently, north is up, every direction is covered, they also have on sight battery storage and I think a ground source heat pump.



Some videos from YouTubers I follow, panels are now so cheap, it is worth doing north facing roofs, you can buy 450w panels for £50 exc vat as that's not applicable.



 
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Amended quote from Skylar Solar.



14 panels across our main roof, kitchen extension roof and shed/garage. 8 kWh Sigenergy inverter and 9 kWh battery (we average 10 kWh per day). Our usage looks on course for 4,000 kWh for Y2 so have some leeway for the 20% rule + induction hob and underfloor electric heating when we get the kitchen redone.

Still seems quite expensive but the other local company likely to come in at a similar price when he amends the quote to match these specs. I liked the look of Heatable but heard they inflate installation costs - initial quote with them is £12k with 10 panels/6 kWh inverter/9 kWh battery/free gateway but not all of the installation costs included like scaffolding.
 
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