Greetings from Captain Joseph L. Naselli
In my unit a model 211 w/ 8.1 L Chevy vortex engine, the engine charges the main battery as well as the two house batteries as you drive down the road. The gen-set also charges the house and engine battery when I am at a site. Using the 110V power cord, the house and engine battery are charged off the 45 amp converter. This is accomplished by the Intellitec system, a circuit board that separates the main battery so that it can not be discharged when you are not plugged in as there are one way solenoids on this board. Therefore you will always have voltage to start the vehicle. If you should leave the van lights on, then by switching the emergency toggle, you will get power from the auxiliary batteries to start the main engine.