Dual battery set-up using chassis battery

Kayteg1 wrote:
In my bus conversion the only way to run AC on the road was via inverter, but bus had original 8kW alternator.
My new truck has dual alternators, so I am pretty confident I could run inverter with AC on it, but having build-in generator I would rather fire it up.
I am not sure if single cylinder propane generator will use less fuel than V8 diesel, but small engine is way easier to replace down the road.
Coming to batteries, driving truck with dual alternators I am very tempted to wire up truck batteries to camper - instead of carrying another 120 lb of batteries.
The issue is that in case I deplete the truck batteries too low, I will have no power to start generator.
So couple of ideas I am planning to check for the future
1- disconnect 1 of truck batteries and keep it for generator start
2 - check if the new technology gizmo will start my generator with low batteries.
Those cigarette pack sized batteries claim to give 400 amp, what is way more than my generator needs.
My new truck has remote start and I already tried it in February, when overnight my camper heater depleted camper battery.
The remote start will run the engine, turn the external lights on, but will NOT activate trailer charging relay. THAT SUCKS !

You try to draw 400 starting amps @ 12 volts through those pencil wires, what you will have is a stinking smoky melted mess in about 2 seconds. neither the cables nor the internal circuitry of that L-Ion pack will take that much amperage. It may well be capable of delivering 400 amps but not all at once. Never happen.