Can the immediate cut off of a load (open output breaker) while powerassist is engaged result in brief moments of backfeed to the AC input? Let's say only 1000W of AC input is available, but there's a 3000W load that's cut off by opening the AC out breaker.
I don't understand the technical aspects or PowerAssist or even inverter operation, but to me, it seems like PowerAssist puts the inverter in a grid-tie-like operation. This suggests to me the possibility that the removal of a load could cause very brief backfeed to the AC input... kinda like when an external BMS opens the charge circuit causing the MPPT/MP charger to briefly spike in voltage before it can clamp down on the output.
