Battery Combiners and Chargers?

Question:

My port starting battery was receiving a charge from the inverter even though it was not hooked up to the inverter. Could this be coming back though a shared device? If that is in fact the case would that also mean the starting battery is discharging when the inverter is in use?

Answer:

An automatic combiner relay (aka voltage sense relay) will only parallel the batteries whenever there is a charging voltage (i.e. 13.3 VDC). As soon as the voltage drop bellows 12.8 VDC the batteries are separated and the inverter loads would only be applied to your house battery.