- Before and after second battery.jpg (109.12 KiB) Viewed 73 times
So was 3.2 kWh now 6.4 kWh and the morning dip much reduced, I can charge batteries now at 4 kW so unlikely to be exporting any more while batteries not fully charged, and can draw 5 kW (limited by inverter) rather than 3 kW before using grid power, and now at midnight, the battery is still showing over 20% (it stops discharging at 10% to leave some for UPS should we have a power cut) but it also means some reconsideration of when to use the big three, that's the dish washer, washing machine, and tumble drier, the three machines which have a built in delay timer, so I can set them to run during off peak.
But off peak still costs 8.95p per kWh and solar is free, so we look at the weather, and decide when to run them, however is that really how we should run our lives?
September 2023 my bill was £70, and September 2024 my bill was £60 this is mainly due to the smart meter and off peak power, and using the battery to facilitate using off peak power during peak hours, we had a 3.2 kWh battery and solar last year, but we were on a single rate tariff.
If I subtract the off peak rate from the peak rate, so work out saving, with that alone the extra battery will pay for its self in 5 years, and it has a 12 year guarantee, but it will also help during the day, so it will take less than that.
But the question is how to use the power to gain the most from solar and off peak. I have off peak for 5 hours, not sure if UTC or BST so only use it for 4 hours, if I stopped using it after 2 hours, I would have a fully charged battery, at 3 am, but by midday I would have still room for more solar, however on a poor day, with no solar, I would run out 2 hours earlier.
To the 17th, (this month) 7 days no export, so 7 out of 17 days, to stop charging earlier I would likely loose money. September 10 our of 30 days, no export. I am using no export as an indication that we would have run out of stored power.
Anyway battery now full, so time to swap the loads in washing machine and tumble drier, and make a cup of coffee, but this must be the same for anyone with solar and batteries, so keen to hear how others use them.