I have a Multiplus and Fronius AC coupled on AC out1. Li-ion Batteries.
When grid fails the inverter takes over.. Fronius continues. as soon as the PV power is higher than the load everything trips, including the ccgx. then the inverter starts up again and restores power on AC out 1. Primo sees life and switches on... bang, everything trips.
if i add a load the the system (heater) then everything is ok. The frequency shift is set up correctly. maybe just not fast enough to reduce pv so that the inverter stays inverting.
So can this system not work in my configuration? using the excess pv to charge while grid is off? Seems as soon as the multi changes from inverting to charging the fronius loses the supply it is latched to.