Perhaps you could connect the batteries together so that they are feeding in parallel during the change-over. There used to be make-before-break switchgear for this purpose, but I guess simple relays are a better solution these days.
Perhaps you could connect the batteries together so that they are feeding in parallel during the change-over. There used to be make-before-break switchgear for this purpose, but I guess simple relays are a better solution these days.