Figured I would update a little on my thread.
I just got finished installing my dual battery set-up. I am using a Xantrex Pathmaker 100 isolator/connector and the remote control panel. Had a little trouble with a bad connection between the remote and main panel, but once I figured it out and fixed it, everything worked like it should.
I installed the auxillary battery in the rear section of my XJ, since there is absolutely no room under the hood for it if you want to keep the stock airbox, and I do because I have my snorkel. This is actually better for me (I think) because I am going to be running a rear winch soon, and will have a place to hook to the winch to without going all the way to the front of the truck. Right now, the front Optima is running only the Jeep and the front winch, the aucillary battery is now running everything else. (Soon to be rear winch, 6 HID aux lights, rear halogen lights, fridge, compressor, inverter, camera, monitor, rear 12 volt sockets, etc.)
Turned out pretty good, was a pain getting all the pre-existing wiring to the rear, but its done. For now I have a deep cycle/starting (800amp) marine battery until I get something in the dry cell group. Installed my littel MV-50 in the box, and the inverter 700watt/1400watt on the top. I also added 3 12volt sockets on the top as well for whatever...
Not many pictures in between, but you get the idea.
~James