I am thinking of two DC busses. A variable DC buss coming of of the PV array which feeds a battery charger and is the normal source for the grid tie inverter. The other buss is the battery pack buss. This feeds any DC only loads like swimming pool pumps. It is the alternate feed for the grid tie inverter.
The output of the inverter is connected to the load side of a isolation switch. When the isolation switch is opened, this would signal the inverter that it is OK to put out AC because the inverter is disconnected from the grid.
Obviously the loads you want to power when the PoCo goes away would be also on the Load side of this isolation switch.
Last edited by LarryC; 10/03/10 08:10 PM.
