I'd hook it directly to the battery thru a CIRCUIT BREAKER ( Not Fuse ) and use a #10 or heavier wire. Make sure you have a real good ground. One of the guys said something about 14.7 volts. Its been my experience voltage consistently that high at the battery with engine running will cook the battery and shorten its life. !3.8 is a good level. The line usually run from the truck voltage source to the trialer battery is to light to give a good charge back there. Serious campers frequently install #6 wire from the truck battery to the trailer battery, thus almost eliminating voltage drop unless a real heavy load is put on. I had #6 on my old truck and could even run thr fridge while on the road. With the new truck I'm jsut going to use gas for the fridge when on he road.
A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more!