How To Size A Home Solar Battery

Start from the evening consumption, not the array size

The battery's job is to move surplus generation into the hours when the house is consuming and the array is not producing. Size it from the evening and overnight consumption you want to cover, then check that the array actually produces that surplus on an average day.

Check the surplus, not the total generation

A 10 kW array on a house with a large daytime load may produce very little surplus. Pull the export figures from the existing meter if the PV is already installed; if it is not, model the load profile against the array output before choosing capacity.

Decide whether backup is part of the requirement

Self-consumption and backup are different specifications. Backup adds a transfer requirement on the inverter and usually a reserve state of charge that is held back from daily cycling, which means more capacity for the same daily saving.

Confirm the inverter handshake before ordering

The most common failure in residential storage is a battery and an inverter that do not communicate. Send us the exact inverter model with your enquiry and we confirm the CAN or RS485 protocol before the order ships.

Leave an expansion path

Parallel-capable batteries let a household start with the capacity that pays back today and add more later. Check the parallel unit count in the specification table before assuming the expansion is available.