How to wire a trailer charging system.

[CCHSNC 14]

What I would like to do is charge a battery in my trailer using my truck. Can some one walk me through this please?

[R L S 14]

Run a 10 gauge wire from your positive battery post to a 30amp inline fuse, mount the inline fuse on your fender well (inside the engine compartment) then continue the wire all the way back to your wire harness on the back of the truck. When you run the wire make sure you avoid high heat areas such as exhaust manifolds and exhaust pipes. If you can find some wires running from the engine compartment to the rear you can secure your 10gauge wire to that using zip ties. Zip tie the wire to keep it out of the way and tight so it doesnt vibrate a hole through the insulation when you drive. You can tie it to the frame as well. Make sure you run it accordingly so that it doesnt interfere with your spare tire if you need to get it out. If you cant avoid a high heat areas wrap the wire with exhaust tape. You can wrap a few wraps of electrical tape around the wire in areas you are concerned about vibrating wear. When you get to the trailer harness in the rear of the truck put an appropiate wire end on it, say a male end and then you put a female end on the 10 gauge wire running from the positive battery post on your trailer battery. That way when you hook up your trailer lights you simply plug in the battery charging wire. Be sure to run a ground from your negative battery post on the trailer battery to the trailer frame.

If you didn't know,undo the battery clamps and fit the stripped end of the 10 gauge wire in between the clamps of the battery and the terminal posts. Auto Zone or any car place will have all you need.

I hope this helps and is understandable, Call me if you have problems Richard 919-478-1979 or email at topnotchpw@yahoo.com

[Pams Pressure & Clean 64]

If your vehicle is equipped with a 7-way trailer connector, the wiring is already done for you.

There is 12v at the plug and a ground.

You need to make a charging harness on the trailer by finding the correct wires and splicing off of them to your charging station.

To find the correct wires you can either look at the connector on the tow vehicle(they are usually marked) or by getting a standard trailer wiring diagram.

FWIW, I have attached a copy of a wiring diagram here.. I found it on the web and can't give credit where due, because I don't remember where.

Sorry it's so fuzzy, but it's all I have readily available..

Hope this helps,

[Mike Williamson 198]

Here's one that's a little larger for the 7-pole.

[Pams Pressure & Clean 64]

Thanks Mike.. That's a much better pic than I have

[CCHSNC 14]

Thanks everyone!!! Thats just what I needed to know.

[BillBosko 14]

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...