Best tariff or strategy for solar/battery

3 Posts

Having recently had 4kW solar and a 7.2kWh battery installed, I'm wondering what's the best current strategy for getting a good return?
I know this is a "how long is a piece of string " question, but there are probably some general rules that can apply.
I'm thinking that a low night rate is good as it can charge the batteries, which can then support the house in the morning until solar kicks in. Solar can then recharge the batteries to cover evening use.
This will reduce usage to zero on a good solar day, but on a bad solar day, I will end up paying for "normal " electricity in the evening at a higher rate (but I'd have had to buy this electricity at whatever normal rate I was on anyway).
Has anybody done a similar calculation recently with current rates for their useage, to give me a clue, and what provider are they using?
I know this is a "how long is a piece of string " question, but there are probably some general rules that can apply.
I'm thinking that a low night rate is good as it can charge the batteries, which can then support the house in the morning until solar kicks in. Solar can then recharge the batteries to cover evening use.
This will reduce usage to zero on a good solar day, but on a bad solar day, I will end up paying for "normal " electricity in the evening at a higher rate (but I'd have had to buy this electricity at whatever normal rate I was on anyway).
Has anybody done a similar calculation recently with current rates for their useage, to give me a clue, and what provider are they using?
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Solar PV 5.25kWp SW facing (14 x 375 Longi) Lux 3.6kw hybrid inverter and 4.8kw Pylontech battery storage installed March 22
Octopus Flux electric and Tracker gas
Obviously I need rhe EV which I'm sorting but it seems worth the calculations to he able to use electric at a quarter of the price when solar just can't do it during Nov, Dec, Jan & Feb
Good performance from the solar. Its 4kWp and I am seeing 20-22kWhr daily production on good days (in May - I only have 3 months data.). Bad days about 5kWhr so far.
Average use of about 16kWhr per day, but that includes excess being diverted to the hot water (iboost). Over three months solar has reduced my bill by about 80% so the standing charge is the most significant cost
Heating is oil. Overnight basic load appears to be about 200-300W.
On a good day, I can be totally self sufficient in power consumption. In other words , normal use means that at this time of year on a sunny day, solar and battery can give all the energy I need for 24hrs.
The winter will obviously be different - I won't have enough solar to run the house or charge the batteries much.
I guess in the winter I can get maybe 1/2 a days electricity from charged battery/solar (if I can charge the battery overnight sensibly) so would need to buy 6 to 8kWhr per day. In the height of summer I wouldn't need to buy anything except standing charge.
Are there any tariffs that I should be considering? Do I actually need an EV for Octopus go?
I also have an oil fired boiler so in the winter I'll use that to heat the water as I'll be running the heating anyway.
I've been measuring my oil tank every day and an hours use to heat my water per day actually uses very little oil.
You do need an EV charger and now an EV I believe for Octopus Go. I haven't found any other tariffs that would fit the use of a home battery apart from economy 7 which isn't really what I want.