I fitted solar panels, and it does seem the inverters vary a lot, my main gain is not the solar panels, but the battery that came with the solar panels. So at 1 am I start charging the battery, and at 5 am stop again the house then runs on the battery charged at cheap rate, until the sun comes up, the 3 kW equipment we use, kettle etc, will often use more than we get from solar, but battery fills the gap, so from 5 am to 4 pm most days summer or winter, we use no grid power except for the shower.
The battery will discharge to 10% the last 10% is held to run freezers and central heating in the event of a power cut.
From 4 pm to 1 am often the battery will not last, it is not worth the price of a second battery to ensure it does last, assuming a 7 year life on the battery, so most days we use 3 kWh to recharge the battery overnight, not really needed in summer, but winter it saves us more than the solar panels do, when I went from single tariff all day long to split tariff designed for EV charging, we saw our electric bill drop £20 per month, we had the solar panels Sept last year, smart meter Jan, and split tariff April, and on the BG app we can see the sharp drop in bills once split tariff went live. Before that the battery over winter would some times remain below fully charged for days.
I will admit having an inverter able to do this was some luck, I had ensured it would work as an UPS, but the idea of charging battery over night was an after thought.
The problem, and for me this still exists, is being paid for export, BG offered a very good rate if you buy from them, and SP also do a good rate, but it seems both use a paper application and getting is sorted is a nightmare, Octopus it seems are better, however to give the EV spilt tariff you need to give the charging point and EV vehicle details, BG don't ask for this.
We thought EV tariff and economy 7 would have been the same, but this is not the case, the EV overnight tariff is lower, and the energy companies keep moving the goal posts, when we had it installed we did not need a smart meter, the rules changed the week it was installed, it may not be a law, but now no smart meter = no export payment.
The thing is we only fit solar panels once, so no one can really compare systems. Yesterday was very bad for solar
our main gain was battery being charged over night, but day before
was more typical, the SOC = state of charge, and you can see the purple line showing the dip 5 am to 7:45 am where the solar was not enough to cover all, then around 9 am started to recharge batteries, and by 11 am fully charged again and 11 am to 5:30 pm we exported excess, (9.2 kWh) then dinner caused a sharp drop, and battery ran out at 11 pm. That is about normal.
So this is the smart meter app display for same day the 4th
showing charging battery then nothing used until battery down to 10%. Switching to £ it shows how evening cost a lot than morning
due to the rate change. (£1.50 including standing charge)
