need help hooking up aux battery 2005

[rchopper11]

under pas seat have red wire and black small wire. traced wires to under drivers seat and red wire goes thru seat and under vehicle and black goes to a box on back of seat?

[rchopper11]

id really like to add 2 batterys under seat. 1 for ac/dc fridge freezer, other for air heater, lights ceiling fan etc.

[Rafaelo]

id really like to add 2 batterys under seat. 1 for ac/dc fridge freezer, other for air heater, lights ceiling fan etc.

RChopper: you will find that the amps a refrigerator sucks, on top of the other stuff, will require batteries larger than will fit in the strangely shaped trapezoidal space under your seat. I know--I tried to find deep cycle batteries that would fit under my passenger seat sufficient for a mere 220 amp hour budget (no fridge, no microwave, no Mr. Coffee--just a computer, a fan, and some lights). I asked a major battery manufacturer. They were stumped. From the sound of it I think you are at the early design stage and need to decide how much power you really need. I strongly recommend you go on Bookfinder.com and get a used copy of Barre, Harold, Managing 12 Volts, How to Upgrade, Operate and Troubleshoot 12 Volt Electrical Systems (mine was about $5). The book will tell you how to budget amp-hours, why you need batteries that supply about three times the amp-hours budgeted, why those batteries need a special multi-stage battery charger (you can't just wire them to the alternator) why that charger should never exceed 25% of your battery's capacity nor more than 50% of your alternator's, and all sorts of other things. It gives examples of standard small, bigger, and huge electrical installations and what would work for each.