Then the battery(s) should be located somewhere near that end of the trailer. Somewhere there is an access door/panel that covers them, but allows changeout. Should have nothing to do with the enclosed bottom. On the other hand, could be anywhere else, but still should somewhere be a door/panel that needs to be looked behind, or under. Sorry I can't help more, but where the power goes in the trailer, wires have to go somewhere to a converter that changes the 120volt to 12volt and then from the converter to the batteries.