Solar battery usage

It’s a crappy cloudy day today. There was about enough sunlight to power the house, but not enough to also charge the batteries.

The sharp downward slope just after 5pm is when I cooked tea and then turned the TV on. That also appears to be a thing. The TV doesn’t use much power really, but if I leave it on for six hours, it does.

Here’s the 18th of August. On the 18th of August I managed to completely drain the batteries before midnight.

This was partly due to there being constant cloud cover and it raining non-stop all day and the panels barely making any power. But the slope is still a bit steeper than normal. That’s because we forgot to switch the PS4 off that had done an update and was then in the middle of a game for some reason.

The 23rd of August was an odd day. Also cloudy and overcast, but then the sun came out just long enough to fully charge the batteries again.

The day before was a good one too. Sunny all day to keep the batteries full, then I turned the oven on for a few hours to cook tea and bake a pie.

I think all this means that in Winter when it’s grey and shit for the whole of December I will have enough battery to run the house all day if we’re careful with power. And if the sun comes out for a few hours sometime before mid-day it’ll charge the batteries up again.

I still feel like I want to stick another panel on my shed and have better batteries in there. The panels on the house catch the morning sun, the one on the shed gets the afternoon sun until the house shades the garden. But then as I discovered last winter, the shed panel doesn’t make a lot of power and the AGM batteries don’t have much capacity. Replacing them with lithium iron phosphate would be good, but be expensive.