94JDH wrote: ↑Mon May 27, 2024 9:43 pm
Getting close to that 100 kWh !
Its theoretically possible, on a good day with 70kWh generation and a 60kWh battery it sounds easy but in practise it never is as the house uses some of that power and if the batteries fill up there will be curtailment.
I'll need a good sunny day and start at midnight with a full battery and full hot water. I'll need an average export of about 4.2kW over the 24 hours.
Say at midnight I set export to 4.2kW (AC) so with the inefficiency and house loads the battery inverter might be using nearer 5kW DC and it will take until 9am to balance out with the solar generation. So thats 45 kWh, maybe even 50 kWh so a really big dent in the battery but workable.
Then I wont need the battery again till 5pm, then the battery will be discharging for another 7 hours so the battery will need a good charge during the generation day but I wont mind the battery getting down to almost my cut off point because the cheapslot will be immediately available when we reach the end point at midnight.
During the solar generation phase I may be able to increase the export to 5kW or 6kW to get ahead of the average and have about 6 hours for charging the battery. That might not be enough to recharge the battery full again but I reckon it will only need to get to around 70% full. The evening will be easier as BST means we are solar shifted by one hour and the bulk of my generation is SW facing.
Sounds like a challenge but there are some difficulties,
1) We have yet to have a 100% sunny day this year so need one of those and preferably in June for the longest generation period.
2) SWMBO will need to have a laundry and ironing ban, that could be difficult.
3) Other loads in the house will need to be minimised, so no heating / air con or roast chicken dinner.
4) Finally, the Octopus might not be too happy with me.