Good shout. Once I get the smart meter installed will start keeping an eye on stats. Been too busy with moving in, diy around the house and getting my office finished off.
Solar panels and battery - any real world reccomendations?
- Thread starter GinG
- Start date
Good shout. Once I get the smart meter installed will start keeping an eye on stats. Been too busy with moving in, diy around the house and getting my office finished off.
Post install ponderings. We have 16kWh of battery storage. At the moment charge up on octopus go at night, topped up with whatever solar generation may happen.
We get through 39 kWh on average per day.
Battery usually deleted by 1700 to 1900 each day. Is this just the winter pattern?
I am assuming in summer we can charge the battery more often and be more self sufficient, prob with night charge top ups, live off the solar in the day, with surplus to the grid.
We are capped at 8kWh selling back to the grid, hence thinking if worth increasing battery size. perhaps another 8 to take us to 24kWh?
Could wait for the first year, see how we do. Possible downside is battery costs may increase.
We get through 39 kWh on average per day.
Battery usually deleted by 1700 to 1900 each day. Is this just the winter pattern?
I am assuming in summer we can charge the battery more often and be more self sufficient, prob with night charge top ups, live off the solar in the day, with surplus to the grid.
We are capped at 8kWh selling back to the grid, hence thinking if worth increasing battery size. perhaps another 8 to take us to 24kWh?
Could wait for the first year, see how we do. Possible downside is battery costs may increase.
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Associate
The general recommendation is about 1 days usage for battery capacity, but at 39kWh per day, that would be a lot of money sunk into batteries!
I think in this case, an extra 8kWh would be wise as it would almost get you through to the cheap time again. You'll be saving about 15p per kWh, so a good £1.20 per day (or £438 per year) if you end up using it all.
My usage is about 11-12kWh per day, so on a sunless day, the battery lasts throughout the peak rate (0530 - 2330). If we get good generation like today, I dump what's left of the battery at 2000-2300 at 15p per kWh, then recharge as normal from 2330.
Thanks looks like battery is approx 3k. So ROI at those rates would be nearly 7 years.
Associate
I've pondered much the same thing; we've gone up to 40kWh last week with the heat pump but now back to 'normal' shoulder season around 15-20kWh consumption with 9.5kWh battery. Generation on a sunny winter day around 5kWh, on a regular one around 3kWh only gives us somewhere around 4-6kWh on the average day that isn't off the battery. Because we've been getting through the battery at a rate of knots we've gone onto the Cosy tariff that lets us recharge at lunchtime which has been a big benefit so we're averaging around 12-13p/kWh with e.g. cooking at peak time exceeding the 3.6kW max discharge rate.
I'm contemplating a cheap DIY system on the shed with 4 panels and a DIY battery kit (somehow need to figure out if I can automate it to not conflict with the Givenergy kit via predbat). Otherwise I've decided to live with it as the actual number of days per year I would fully utilise extra capacity at Givenergy prices doesn't seem worth it. I got numbers like reef said around £1ish per day but you only really fully utilise that on the days you actually need that much electricity so you need to discount it a bit. Plus if you're taking credit for cash flow from export, depends on how long you think 15p/kWh will be available.
Soldato
All connection paperwork signed off by my DNO……happy bunny.
Eventually I want to switch over to a fully electric system, with 12 panels on my South facing roof and battery storage.
I work from home and do use a good amount of electric each day and I'm on the fence about getting a heat pump to replace our 20+ year old system boiler, so it's an expensive decision to make.
Watching this thread with interest.
I work from home and do use a good amount of electric each day and I'm on the fence about getting a heat pump to replace our 20+ year old system boiler, so it's an expensive decision to make.
Watching this thread with interest.
Solar is a no brainer if you have the capital to spend on it.
Heat pump depends on the cost and assuming the cost to retrofit is not silly, it’s another no brainer with the grant.
I’ve got both and my bills are now nonexistent, as in near zero. My DD is £20/month and even then I think I’m overpaying, that also includes powering the car so no petrol/diesel bill either.
My heat pump install was only £3600 after the grant, bargain IMO.
Heat pump depends on the cost and assuming the cost to retrofit is not silly, it’s another no brainer with the grant.
I’ve got both and my bills are now nonexistent, as in near zero. My DD is £20/month and even then I think I’m overpaying, that also includes powering the car so no petrol/diesel bill either.
My heat pump install was only £3600 after the grant, bargain IMO.
Did you use a local company or a larger national one?
I think a basic quote for a Heat Pump was around £4K and 12 solar panels with 4kw battery around £9K.
I've just had my quote through for panels on the workshop roof -- a really reputable company, but you pay for it. The total outlay is ~22k. That includes:
14x JAM54D 440w panels
Tesla Powerwall 3 11kW inverter
Tesla 13.5kWh battery
Need to digest fully.
14x JAM54D 440w panels
Tesla Powerwall 3 11kW inverter
Tesla 13.5kWh battery
Need to digest fully.
Soldato
why 11kw inverter?? have you done a fast track G99 for the DNO so you can gauge how much export your allowed?
That price is way over the top
I'm not sure --- 14 is the max panels the workshop roof can take so there is no future growth expected. I haven't had them talk me through the quote yet. I know zero about solar so using this as a stalking horse to start properly researching.
None of these firms will touch my roof anyway (pitched professionally built equestrian barn) so I'll be doing panels myself I think. That means I am only paying someone to connect it up really - so I can buy whatever I need off of the open market.
Soldato
but wont be able to export without a valid MCS certificate, so could be wasting thousands on equipment and export..
i mean you canr even do a fast track on the tesla as its above 10kw to gauge your dno on whether they will accept it or not.
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Soldato
@dlockers one red flag for me is 6kw panels, with 11kw inverter....... doesnt make sense, unless charging batteries from grid on cheap rate