I run dual Odyssey battery's and have for at least 12 years. My battery's are mounted in the back on each side. I made my own cables out welding cable 0 and 1 in size. I do not run an isolator or switch and have never had a problem and I have worked the winch for long periods. I also have a 180 amp GM style powermaster alternator, the system has worked flawless all these years.
Sidenote. My tow rig is an 04 Ram 2500 CTD and it came with dual battery's. One day I was checking out the system on it and it does not have an isolator or switch of any type either.
