Charging 24v Bank from 12v Alternator

[Landyacht]

Vanner, Inc. makes a battery equalizer. Designed to maintain the upper and lower 12V banks of a 24V system at equal charge, even when drawing power from the 12V center tap. I have a friend who maintains the batteries when parked (docked) with a 12V charger connected to the upper battery and lets the Vanner take care of the bottom one. Seems to have worked well for him over the years.