The engine alternator will maintain both chassis and house batteries through the battery isolator system.
The alternator will recharge the weaker battery system first and this is accomplished through the battery isolator. It is recommended before taking a trip or putting coach into storage to make sure to either connect the shoreline or run the generator until all batteries are fully charged with the house charger.
Do not expect the alternator to recharge dead batteries completely. Damage can occur to the alternator when running for an extended period of time with low or dead batteries.