well on most or many rv's there is a battery isolator which isolates the motor and house battery from each other- the alternator feeds the isolator...the isolator feeds both batteries when the motor is running
my pleasure-way has a surepower 16023A- a blue box on the fiewall about 8' x 4" x 3" it has terminal for 3 big cables and a smaller terminal which tells it when the motor is running- or not.
this is a diode type isolator- and a diode will usually drop the voltage from the 14.8 the alt puts out to about 13.5...so metering your battery when the motor is running- if you see 13.5 instead of 14.8 ( at say 2000 rpms) you know there could be a diode inline.
your house battery may have a big switch to isolate it- if this is off then the battery is isolated and does nothing.
If you are on shore power, the AC gets converted to DC and that runs all the stuff in the back- and if your battery is switched "on" it'll likely be recharged from shore power- if switched off it won't
when van is running there shouldn;t be any reason for shore power..so i haven;t tried to work that out.
if you are running van for heat- get a space heater and plug it into the shore power
the ac has a switch and will auto switch where is "sees" power whether that is the genny running or shore power.
hope this helps, Mike
