One thing to remember, and I found this out the hard way, is that the battery charge wire coming from your truck harness was only designed to charge a small motorcycle battery for the trailer brake-away system. If your battery gets low and you are drawing any amps from it, it will melt the wire and could cause a fire. In addition to this, if your truck battery ever drains and it is plugged into the trailer the truck will try to draw its juice from the trailer battery, causing it to get overheated as well. I used to haul RV's for a living and it was common knowledge that the best way to get the job done was to run a heavy wire (8-10 guage) From the battery with an automatic reset 30 amp breaker, AND a switch on your dash so that you have the ability to turn the "charging system" off/on...