Parts Needed to Add an Auxiliary Trailer Battery

Question:

Last year I purchased and installed a trailer braking system from you guys. To do this, I had to upgrade the 4 wire harness to 7 wire, and install the connector box. All pretty easy. Now I’d like to add an onboard battery. From what I’ve read, I think it’s as simple as wiring the deep cycle marine battery into the connector box to the same terminal I connect the power from the vehicle. Would this w charge the battery as well? In this case, would I only need the battery, a box to place it in, plus wire and connectors that I already have?

asked by: Mat H

Expert Reply:

Yes, it is pretty simple to do. All you'd need to do is run a wire # 10-1-1 from the 11 o'clock position on your 7-way connector to the positive terminal on your battery, which is the 12 volt circuit.

This is going to provide a maintenance charge to your battery so it won't die, but it's not going to fully charge it. You'll want to ground the battery to the trailer frame as well.

If you're planning on using the battery for something small like interior lights, then you won't have to worry about your vehicle's battery getting drained, however it if you want to keep your battery fully charged you'll need to add the Redarc In-Vehicle BCDC Battery Charger - Single Input # RED96FR.

This is going to make sure there is no back feed going to the trailer's circuits as well as keep your vehicle's battery topped up at all times.

expert reply by: Bryce D