Joe,
I see your point. The 12v source would be the batteries, I doubt any 12v usage would be picked up directly from the charger. I don't understand why the inverters would come on when 12v is needed, that doesn't make any sense. The Freedom 25's do have an idle function when inverting, but if the inverters are turned off, the 12v usage should just come from the batteries and the chargers would maintain voltage and stay in float. Mine never comes out of float even with a full load of 12v and the digital meters show the float charge maintaining the voltage.

Gary - Trying to help, but at a loss as to why the inverters would come alive for 12v usage.

Joe - Sorry for the link screw up, Ben fixed it.