I have 2x9.5 batteries on an AC3.0 inverter.
Wonderwatt schedules have an option to use an 'Auto Charge Rate'.
This might mean that instead of overnight charging at 3kW for 4 hours, it would charge the battery at 2kW for 6 hours.

Is this better for the battery and/or inverter or just the grid?

  1. Given that the 9.5kWh is also used elsewhere with other inverters with a higher max charging rate, and
  2. With 2 batteries on the inverter, each battery is only receiving 1.5kW when the inverter is charging at it's maximum of 3kW.