Originally Posted by georgetown350
Usually while driving the engine batteries get charged first then the house batteries but when plugged into shore power the house batteries get charged first.
That's not usual for my '02 Itasca and AFAIK, most Winnebago gas chassis RVs. In these, when the ignition is turned on, the engine battery activates an isolator solenoid which puts the engine and house batteries in parallel. This charges them simultaneously. Some RVs have a diode isolator.
When operating from shore power, the converter charges the house batteries only. Many people now install a small 'trickle charger' to keep the engine battery pumped.