Solar Stats #2 - April 10th 2023

Reading time: 2 minutes (373 words)
Author: @pugmiester
Tags: solar , energy , battery , stats

System specs

16 x 390W panels (6.24kWp) facing almost due south with some shading
GivEnergy 5kW Hybrid Inverter
GivEnergy 9.5kWh battery
System Location - Manchester, UK


Generation for the week

I’m grabbing data from the GivEnergy cloud because it draws pretty graphs, so I don’t have to.

Solar generation and usage chart

The weather didn’t do us any favours for the second full week of April. We had a lot more overcast days so a lot less generation. We still exported over 47kWh to the grid because we had no way to use it.

We’ve been trying to make better use of what we generate by having Home Assistant use a solar forecasting service to set the home battery to reach a percentage state of charge based on the expected solar for the next day. If we’re forecast a low amount of solar generation tomorrow, we set a high charge level and top-up on cheap overnight electricity. If we’re due a high amount of solar, we set a low charge level and let the solar fill the battery instead. If we have more solar than we need to refill the battery, and Eddie (our EV) is at home, we start sending the excess to the car for free solar miles. The forecast as been a little hit and miss but it seems to be improving as the weather gets a little brighter. I think it gets skewed the most during the early part of the year where we pickup quite a bit of shading from the house next door and the forecast services doesn’t have a good way to model that.

We’re also showing a lot of grid import too. Some of this will be topping up the house battery overnight, again based on the solar forecast from Home Assistant, but the bulk will be charging Eddie, our EV, using the Octopus GO tariff. I still need to find a way to easily show how much of our import is for charging the car and how much is for running the house directly or charging the home storage battery but that’s a challenge or aother day.

If you’re intested in joining Octopus, we have a referral code (https://share.octopus.energy/super-crane=314) where we each get £50 if you choose to signup.