Battery isolators
Battery Isolators from Victron Energy – Efficient Charging of Multiple Battery Banks
Battery isolators from Victron Energy make it possible to charge multiple battery banks from a single generator without risking draining them from each other. The isolator distributes the charging between the batteries, so you can charge, for example, both the starter battery and the service battery simultaneously. Battery isolators are perfect for boats or motorhomes where different battery banks need to be kept separate but still charged efficiently.
Usage example: Charge the starter battery and the service battery simultaneously without risking draining both.