What difference has a home battery made?

Around this time last year I wrote about how we had got a battery system installed in our house. It was discounted as part of a community buying scheme, and we bought it to support our solar installation. With a year of data, I can now see what difference it has made to the amount of our own energy we can use.

The graph below shows the amount of free electricity we get from the solar panels, before and after installing a battery.

Before fitting the battery, we were getting around hal...