Does anyone have experience or ideas about onboard batteries? I need more battery power over what the stock size battery in the XJ can provide. I would like to put another one in the rear or where rear passenger seat used to be. Whats the best way to do it and is there any notable safety concerns? Thinking maybe one of the new type crossover batteries that are both deep cycle as well as cranking battery. Need something to power winch and as backup if main goes dead. Any ideas folks? Thanks.