What is the “quarter-capacity” matching rule for solar and battery sizing, under BESS5?

It applies to the total rated DC capacity of new solar PV panels, not the battery inverter. This requirement for BESS3, BESS4 and BESS5 intends that the new solar PV array has sufficient generating capacity to supply at least 25% of the battery’s usable storage capacity.

For example, a 100kWh battery system requires a minimum 25 kW solar PV array connected at the site.

The Usable Battery Capacity must also not be more than 6 times the Battery Inverter Output for activities BESS3, BESS4 and BESS5.