Replacing a battery does not change the grid connection, so no new grid-code certification is triggered. For systems installed in 2018–2021, that is worth more than the hardware saving.

Average daily kWh is the number everyone quotes and the number that gets projects wrong. Here is the sizing method that survives December.

CE marking is not a grid-code certificate. Here is the difference, why it decides whether your project can be commissioned, and three legitimate routes if you need export.