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.