Solar Panel System quotes

slateral

I have received two similar quotes - one for a 4kWp system with 5kw batteries for £8k and the other for a 5.8kWp system and 6.4kW batteries for £10k.

Both propose the same make of kit with a Solis inverter capped at 3.68 export. I am now with Octopus Energy and planning to get on the tariff with SEG at 7.5p/kWh (no idea how long that’s going to remain of course).

My house is South of London, roof is 10 degrees off due south and 40 degrees inclination, no shading.

I assume the larger system may offer an advantage in the winter months and on cloudy days? Or would it be a waste of an extra £2k?

94JDH

slateral said:

I have received two similar quotes - one for a 4kWp system with 5kw batteries for £8k and the other for a 5.8kWp system and 6.4kW batteries for £10k.

Both propose the same make of kit with a Solis inverter capped at 3.68 export. I am now with Octopus Energy and planning to get on the tariff with SEG at 7.5p/kWh (no idea how long that’s going to remain of course).

My house is South of London, roof is 10 degrees off due south and 40 degrees inclination, no shading.

I assume the larger system may offer an advantage in the winter months and on cloudy days? Or would it be a waste of an extra £2k?

Pricing seems a bit high on the 1st quote but a bit better on the second - as long as your inverter is a 5/6kW version.
Yes it will benefit from better generation on poorer days as you've a larger PV array. It all depends on your usage.

slateral

Thanks for your prompt comment, 94JDH. Yes it is very dependent on usage - I'm in the 8000-9000kWh/year consumption range, but maximising the use during the day when the panels are generating is, I suppose the key to maximising efficiency.

I don't have an EV to charge which would help consumption, but they don't come cheap and I understand currently have very extended lead times anyway.

Magnitio

The second quote does look better value and, as you say, will provide you with extra capacity during the winter months and cloudier days. The output will be limited by the inverter during the middle of the day when it is particularly sunny, unless the surplus output can be soaked up be the battery. If your battery was full, then on a sunny spring day when your panels could generate 30kwh, the inverter might be able to cope with 25kwh of that potential. This might not be too much of an issue to you if all of that excess was going to be exported, and is compensated for by the better production the rest of the time.

Solarchaser

I have to say I don't think either quote is particularly good.
The 4kw of solar should be £4k or thereabouts. 
Similarly the 5.8kw should be say £6k

Batteries should fall around the 2kwh/£1000 installed at worst imo as you can pick them up as Joe public for £800, so I'd say both are high.

As a 8mwh user, you will definitely benefit from batteries imo (as an 8mwh user) but perhaps you would be better separating the two systems. 

A quick ebay gives a disappointing £3350 for a lux with 4.8kwh of batteries, though that is installed, id still expect it to be about £500 cheaper than that personally. 

https://www.ebay.co.uk/itm/325158484291?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=ctVHDVuhTyS&sssrc=2349624&ssuid=DtbsXk1pRsq&var=&widget_ver=artemis&media=COPY

Midsummer sell the 4.8 pylon at £1715 delivered, and I'd assume you can pick up a sofar or lux for £800 ish but if you are not keen on messing with electrics I guess you would need to pay a spark £200 ish to wire it up.

I guess the recent energy price rise has pushed up the demand for solar/batteries

arty688

I think the days of £1k per kw are gone for a while so for the 1st quote you are probably looking at £5k for the solar and the second £6.5k for the solar.

I don't know but is it legal to install the batteries yourself ? You would also struggle to get a sparky to do the work unless they were a mate or knew the stuff they were wiring up.

Solarchaser

Well a friend of mine in Edinburgh is getting panels in two weeks time for under £1/w so I disagree.

And of course its legal to wire up yourself, you can pay a spark to test the house afterwards. 

If paying a spark to wire it up, we'll its a very simple thing, the spark will supply 2.5 t&e cable to the input of the inverter.
The battery and comms leads are very obvious,  so anyone can do that, plus the manual has instructions if you were really stuck.

arty688

Maybe things are different north of the boarder , but in the last 12 months the cost of all the materials have gone up as well as the labour then add the demand has sky rocketed which all leads to rising prices. I personally had quotes 12 /18 months ago and then recently had re quotes a couple of months ago and they all increased substantially and if I was looking to the prices would have risen again.

Just don't want to give people false expectations when budgeting .

Magnitio

The quotes are for South of London, possibly one of the more expensive areas of the country for an installation. Just getting the scaffolding set up costs a small fortune at the moment.

Boffinboy24

I do think this varies by region, and demand is sky high. When mine were installed in January I had several quotes - and I assume parts costs have only gone up further - all about £1.5 per kWp, I got mine down to £1.3. Admittedly I needed fairly extensive scaffold. Some installers didn’t even want to discuss price, I guess if they don’t need to to discount to fill their time, why would they? I think it’s fairly misleading that people are pushing for £1 per kWp in current climate - it’s clearly possible, but definitely not everywhere and not necessarily easily. 

Solarchaser

I'm not convinced it varies by region as much as you think.
I've had two friends contact me in the last week to ask if £6k for 4kw is a good price, both in the Scottish central belt, obviously both I've advised to contact our mutual friend who is paying less than £1/w.

For me, the message is, shop around.
You want the company that can't do it for 6 weeks, not the one that can do it next week