Hey fellas, need a little help. My son's Boy Scout troop has a trailer that I've been designated to pull. It's a 16' cargo trailer. Anyway, we have 2 lights inside that run off of a car battery in the trailer. The Scoutmaster wants me to wire the battery in so that while we are running down the road the tow vehicle system charges the battery in the trailer. That way when we get to where we're going, we have lights if needed. I also want to put in a switch that will allow us to disconnect from the tow vehicle system if needed. I can probably figure this out eventually, but, what I was wondering was if anyone knows of a site with a schematic to follow. It would speed things up. Anyway, any advice is welcome as usual. So let me know.
Thanks

 

Try this I had a truck an old one at that, what I did was run a Welding lead wire from my Truck battery it had a jumper cable end that I would connect to positive when I needed power out the back. The other end was a male to female connector for the positive and then had a short female to male connector for the Ground. So as not able to get anything crossed up. and these ends that came out the back by the bumper they were held in place by a u-bolt. These ends are from a welding supply store that you can get. They are meant to be able to hook another welding lead to for more reach. Then on the trailer I had the ends mounted and short wires for operating a electric winch or what ever I wanted to. The battery on the truck was charging the battery on the trailer if I wanted too or work the winch when I wanted to. Hope that gives you a little start on what you want. Good Luck

 

Look here for the wire outputs from a 7 pole RV recepticle. http://www.rverscorner.com/wiring/7pole.html

#4 is used to charge the trailer battery, although you won't get much more than 10 or 15 amps through it with stock Dodge factory wiring.

 

So it would be cool to wire a battery on the trailer to one of the truck batteries and it would accept a charge?

 

Not knowing the history of the cargo trailer battery and how long it may have sat I would hook up a battery charger to the trailer battery first to make sure it charges and is at full charge. Then all your truck has to do is maintain that charge.

You don't want to find out that the trailer battery has a dead cell or won't hold a charge while on the road.

 

I have a 1977 Airstream Trailer, haven't pulled it with the Dodge, but on the 89 Ford 7.3 I got rid of, I ran a 3 conductor 10 guage cable from the batteries to the 7 pin connector (the Airstream uses the Big Rig round 7 Pin connector) on the truck end. Connected the hot lead to the + and the ground wire to the - side of the battery, used the other lead for the trailer brakes. The trailer cord has a 10 gauge wire for the batteries and the batteries are located in the front of the trailer. The truck kept the batteries charged, never had a problem. Of course you need to drive a few hours to charge up a low battery and I always started with a charged up battery. Just be sure not to leave the trailer connected, because if someone leaves the light on you could end up with a dead battery. You can also wire a relay in the hot side that is only on when the truck is running. Get a heavy duty one from a rv dealer.