@CurlyParakeet @PetraPhoenix The other side of this (which wired in inverters do too) is a direct feed inverter (ie: designed not to operate with out the grid) use that feed in from the grid to a) sync up their sine wave to the gird, because if your system is say, 1Hz off the gird, this is Bad(TM). And b) so if the grid fails, you don't back feed it and kill the poor tech down the line fixing it!