I bought a Jayco camper built on a 92 chevy g20 chasis. It has an aux deep cycle battery to run 12 v fridge, vent fan & int lighting which is charged by main 12v system when driving & 110 v converter when plugged in. I think this battery needs replacing because it doesn't take much of a charge, but I haven't been able to locate it. Can anyone tell me where it is? Thanks - Jim.