I have an AC-coupled PV inverter and use the Multiplus II in ESS mode connected to AC in.
If the battery is full, the Multiplus immediately starts discharging the battery with about 55W. Then after some time, it starts charging again, i.e. cycling between charging and discharging which deplects the batteries. Also, as there is still enough solar power available on AC, there should be no discharging, but the Multiplus should use the solar power provided on AC.
This seems to be a bug in the ESS. Solar power should have precedence over battery power.
