Second battery
Our camper has only room for one group 24 battery. A few years ago I added wiring and a multipoint switch for an additional battery to go ahead of the rear wheel well but have not used it until now. ...
Forum Discussion
Hard to give a good answer without more information.
If the "old" battery is more than 3 years old and/or has been run WAY down more than once, I think it should be replaced too.
No need to separate two batteries into "banks" unless one is a LOT bigger than the other. Two the same in parallel is the most common arrangement in a situation like yours. Unless you got real fancy with the cables, the added one will tend to discharge and recharge slower because of the cable lengths.
If the "old" battery is more than 3 years old and/or has been run WAY down more than once, I think it should be replaced too.
No need to separate two batteries into "banks" unless one is a LOT bigger than the other. Two the same in parallel is the most common arrangement in a situation like yours. Unless you got real fancy with the cables, the added one will tend to discharge and recharge slower because of the cable lengths.
