Solar PV + 5kwh bat...
 

  You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more

Solar PV + 5kwh battery + immersion heater quote?

34 Posts
23 Users
0 Reactions
125 Views
Posts: 499
Free Member
Topic starter
 

For various depressing reasons I'm lucky enough to have some money.

I'm interested in Solar PV for all the obvious reasons (£ saving and environmental impact) but for equally obvious reasons it's proved impossible to get more than one quote.

So, asking for experience, is this reasonable? And also, is it a sensible use of £13.5 k?

£13,500 for Supply and installation of:
5.925 kWp solar PV (3.68kW Hybrid) with 5kWh Battery bundle, a Sun2000 450w Optimis and an iBoost (so the power is used to heat the immersion heater).

It's from a local company with good references who fitted a friends system years ago, so I'm pretty confident, but It's a lot of money and without another quote it's hard to see if it's reasonable. I think it is but would appreciate others experience.

The alternative is to put the money into my pension, that's probably a better rate of £ return. The company say ~11 years to payback at my current electricity price, 28p per kWh. I think most people see this going up pretty consistently for the next few years so the payback may well be sooner.

Tricky (at least for me) so any advice welcome.


 
Posted : 14/08/2022 8:29 pm
Posts: 7932
Free Member
 

Seems expensive to me. I paid ~£8k for 12 panels, 5.2kWh of storage and installation. The iboost thing is £300 and can be DIY installed without difficulty.


 
Posted : 14/08/2022 8:48 pm
Posts: 39449
Free Member
 

Depends on what the panels and inverter are

But on the face of it for 5kwh battery storage and a basic 3.68kw panel set up it seems steep.

But we don't know what your roofs like.

For context I've paid vat 5% on panels and 20% on battery and replacement inverter .... As a victim of both the bad timing and rapidly changing technology awards....

I'll have had 2 inverters and I'll still be ~14k and my batteries will have twice the capacity.....


 
Posted : 14/08/2022 8:50 pm
Posts: 0
Free Member
 

Going on our recent quote that seem a little steep but not overly so. Does it include scaffolding?


 
Posted : 14/08/2022 8:57 pm
Posts: 499
Free Member
Topic starter
 

Thanks all. Yes includes scaffolding (and everything else). Appreciate the price calibration, I'm on the fence and with your feedback think I'll put it in my pension. With my current form I'd probably fit the panels then promptly move! 😆


 
Posted : 14/08/2022 9:09 pm
Posts: 18073
Free Member
 

I have no idea how well insulated your house is but insulation is usually the best return on your investment in both economic and CO2 reduction terms. Your proposed solar system will get you maybe 3-4000kWh over the year, now have a look at your heating bills and convert those to kWh. £13k buys you a lot of insulation.


 
Posted : 14/08/2022 9:12 pm
Posts: 4359
Full Member
 

It’s only a little more than the quote I had last week for basically the same thing (£12.5k for us).
Won’t  be happening here for a while at that price unfortunately, maybe in 6 years when the mortgage is cleared…


 
Posted : 15/08/2022 6:41 am
Posts: 3265
Full Member
 

Put it in your pension if you have allowances left and can wait to spend it. ‘Instant’ boost from HMRC should offset some of the market wobbles.

Our recent quote included ~£12,000 for 11kW PV + inverter.


 
Posted : 15/08/2022 6:58 am
Posts: 11486
Full Member
 

How does a hot water panel (those black tube things) cost up, for directly heating water without that pesky electrical conversion)?


 
Posted : 15/08/2022 7:04 am
Posts: 10539
Full Member
 

Seems about right. Maybe a little expensive, but given the current star of supply, not too bad.

Ours is £17k but it’s inset and and with a 13kw battery and no iboost.

I recon 7.5y ROI assuming new electricity costs at 40p/kWh and charging the battery overnight on cheap rates during the winter months.

It’s also an asset - a home improvement that adds value to the home when/if you come to sell.


 
Posted : 15/08/2022 7:10 am
Posts: 1208
Full Member
 

I'm getting quotes now. First quote

14 400W perlight panels 5.6 KW
6.5 KW Growatt battery
3.64KW Growatt hybrid inverter
Bird proofing
MCS and DNO notification
12.5K

In Kent and a local installer, lead time of 4-5 weeks currently


 
Posted : 26/08/2022 11:23 am
Posts: 12865
Free Member
 

@leegee You've missed out this year (as did I!) but KCC have been running a scheme for the last couple of years called Solar Together. It's a group-buy thing to get the price down and includes the Growatt battery IIRC. I got a quote a couple of years ago and now wish I'd pulled the trigger, it was VERY competitive. They were actually over-subscribed this year so by the time I got my arse in gear they'd closed the books! Hopefully they'll be running the scheme again early next year.

Be interested to hear what your quote is (& from who), I am in Kent as well!


 
Posted : 26/08/2022 11:30 am
Posts: 1208
Full Member
 

Zilog, I'll send you a message.


 
Posted : 26/08/2022 11:45 am
Posts: 39449
Free Member
 

read up on growatts software before committing and how their inverter start up current required.

by all accounts its pretty frustrating.

cheapest system Kw for Kw though


 
Posted : 26/08/2022 11:50 am
Posts: 12865
Free Member
 

read up on growatts software before committing and how their inverter start up current required.
yeah, I have done very little research on PV/battery system so need to start reading up! Would love a Power Wall obviously but £££


 
Posted : 26/08/2022 11:59 am
 IHN
Posts: 19694
Full Member
 

Slight kinda hijack; in a very rough piece of string length estimate, how much would I be looking at to add a battery to an existing PV/iBoost installation?


 
Posted : 26/08/2022 12:03 pm
Posts: 1208
Full Member
 

IHN, don't hold me to this but 5-7K for a 5-6KW battery

@trail_rat noted, I've a had a quick look but cant find any horror stories.


 
Posted : 26/08/2022 12:14 pm
 IHN
Posts: 19694
Full Member
 

IHN, don’t hold me to this but 5-7K for a 5-6KW battery

Ta


 
Posted : 26/08/2022 12:38 pm
Posts: 10567
Full Member
 

Snip a bit off the new spring to increase the pressure.

EDIT: That's weird: I posted this on the Molgrips tinkering with something else that's disappointing him thread and it ended up on this one.


 
Posted : 26/08/2022 2:32 pm
Posts: 11269
Full Member
 

I have a Tesla power wall battery fitted by housing association to my bungalow that was intended to allow me to store cheap electricity at night then use the battery to run my house/air source heat pump during the day but I switched off my air source heat pump in January, I now use between 4kw to 5 kw a day - roughly how much would a suitable solar system cost to be fitted to allow me to use the battery storage?.


 
Posted : 26/08/2022 2:41 pm
Posts: 13741
Full Member
 

Need way more info, how much roof have you got? max out area if you can  and what's its aspect any shading on roof?

https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html


 
Posted : 26/08/2022 2:47 pm
Posts: 3315
Full Member
 

@leegee- I'm in Mid Kent and would be interested in the supplier details too please if you could pm me. I prevaricated over the KCC offer & missed the cut off as well.


 
Posted : 26/08/2022 2:47 pm
Posts: 1208
Full Member
 

FB, I've sent you a message.


 
Posted : 26/08/2022 3:05 pm
Posts: 11269
Full Member
 

Need way more info, how much roof have you got? max out area if you can  and what’s its aspect any shading on roof?

West facing roof (277degrees) with area of 9m x 6m (estimated), no shading on shoreline of solway coast with uninterrupted view of sky, 1 bedroom council/housing association bungalow. I'll have a hunt around the solar pv sites to get an idea of costs/suitability


 
Posted : 26/08/2022 3:08 pm
Posts: 4313
Full Member
 

 insulation is usually the best return on your investment

unless you live in a timber framed house built in the 1960s with no insulation, in which case you're looking at £20,000 for external insulation and £15,000 for double glazing. Or pulling off all the plasterboard, adding insulation to the frame, replastering and redecorating.

Back to the original subject, I was quoted £10k for 6kW of panels and 7kWh of batteries in April. Estimated output is 4540 kWh per annum. With the electricity price going up to 52p / kWh that's £2,363.40 saving per year


 
Posted : 26/08/2022 3:15 pm
 ajc
Posts: 212
Free Member
 

The problem with a calculation like you have done above is that you have forgotten the sun shines in the summer a lot and hardly at all in the winter. You can’t store all of that summer generation in your 7kwh battery to use in a different season.


 
Posted : 27/08/2022 10:06 pm
Posts: 13916
Free Member
 

Exactly.
You'll struggle massively to use so that the panels produce in the summer, so your actual savings will be lower.


 
Posted : 27/08/2022 10:19 pm
Posts: 4170
Free Member
 

6kW of panels and 7kWh of batteries in April. Estimated output is 4540 kWh per annum. With the electricity price going up to 52p / kWh that’s £2,363.40 saving per year

A bit less than that. You're unlikely to use all you generate in summer; if your 6kW panels are running at 4kW, unless you're at home and using power your 7kWh battery will be full in less than 2hrs, so will start exporting, and you're not going to get 52p/kWh for export. Also you lose maybe 5% of what you put in the battery due to charge/discharge efficiency.


 
Posted : 27/08/2022 10:26 pm
Posts: 39449
Free Member
 

The problem with a calculation like you have done above is that you have forgotten the sun shines in the summer a lot and hardly at all in the winter. You can’t store all of that summer generation in your 7kwh battery to use in a different season.

While kept being told this over and over before I bought my solar panels.

The data we have got since indicates that there's only one month (December) that doesn't generate an average of 5wkh. (At 57deg north on a 55degree unobstructed south facing roof)

If we can capture all that then it lifts the utilisation from 38% to >85%+ as it's rare your generating when you want to use if you have a normal job.....timer/smart home can only do so much for your utilisation.

All that said If you have a hot water tank(I don't)then a solar immersion timer would be my first port of call for storage of excess.


 
Posted : 28/08/2022 8:53 am
Posts: 5720
Full Member
 

Hang on. 28p/kwh? I have just been quoted 62p/kwh for renewal in October. Would that change your maths?


 
Posted : 28/08/2022 10:59 am
Posts: 9763
Full Member
 

If I fit Solar panels to my house today can I sell electricity I’m not using back to the grid?


 
Posted : 28/08/2022 11:21 am
Posts: 39449
Free Member
 

Yes however you'll be selling at cheap times and buying at expensive times on current agile tarriffs without a battery.

The way things are atrhe moment and will almost always be due to transformer set up is that when solar is producing they almost always don't want your power due to it rarely being produced at peak load.

Flat rate SEG is 4pence/kWh

Hence why self use is so important. Import the least you can- export the least you can.


 
Posted : 28/08/2022 11:26 am
Posts: 4170
Free Member
 

Estimated output is 4540 kWh per annum. With the electricity price going up to 52p / kWh that’s £2,363.40 saving per year

That looks a good saving, but you might want to calculate the return for just the panels, not the battery.

The payback for adding a Tesla Powerwall to my existing system is 12-18 years. My actual output from a 3.8kW system averages 2950kWh/year; that's slightly better per installed kW than your estimate. Over a year, I think we use roughly 1500 to 2000kWh of that and therefore export about 1000-1500kWh (we've only recently had an export meter, which is why I've had to guess a bit). In summer, we generate an average of 6kWh/day, but it varies from 3kWh to 15kWh. We import an average of 6kWh/day from the grid (the daily figure will vary as well). So the 13.5kWh capacity of a Powerwall 2 is about right to capture and use most of what we generate (a smaller battery would fill up too fast). So we would avoid importing 1000-1500kWh. But we get 5p per kWh for exporting it (and we might reasonably expect that to go up?) so at best we only gain 47p, ie, £470-700, against the cost of a Powerwall, including average installation cost, at about £9500.


 
Posted : 28/08/2022 9:21 pm
Posts: 6690
Free Member
 

Is is possible to DIY any of this?
How much are the parts??

I could quite easily put some solar panels all over the garage roof and we live on south coast so far amount of sun.

A 12v 250ah (3kw) leisure battery only seems to be 450 quid or so, though I understand you need to overspec as you can't use the whole capacity etc. Maybe they won't stand up to home use I don't know.


 
Posted : 29/08/2022 10:12 am
Posts: 13916
Free Member
 

Is is possible to DIY any of this?

Probably the panel/inverter installation and the basic wiring but you'd need an electrician to connect the inverter to your house electrics.

How much are the parts??

Right now..... Lots!

I have PV on two houses and back in the spring was thinking about adding more (ground mounted) to at least one of them using used panels off eBay.

Hopefully I can find the money and some at a reasonable price this winter.


 
Posted : 29/08/2022 10:47 am

6 DAYS LEFT
We are currently at 95% of our target!