We have a dash indicator, as well as a monitor for what both sets of batteries are up to. I checked ours, just now: sitting at 13.7, like it always does when we're on shore power. After a cruise and dry camping, the coach batteries take a while to get up to snuff, as they do in a pedestal power outage, even with the gen set running. We have a switch, that will inject the engine alternator into the coach, never used it. Good idea, though! ^.^d