Installing Additional 12-Volt Accessory Power Circuit to Trailer

Question:

I installed your 4 pin flat to 7 pin round adapter. I bought the jacketed 2 wire you sell by the foot and ran it from the engine bay to the adapter at the hitch. I installed the 40amp breaker in the engine bay as well. It works great with the RF controller! Now, I am considering hooking up the purple wire to charge my battery that is in the trailer. How do I do that? Do I need to install a seperate breaker in the engine bay and run a new lead from the battery to that wire or does the wire that connects to the purple wire need to be connected from somewhere else? Thanks.

asked by: Doug B

Expert Reply:

I do not have a schematic available, but I would be happy to run you through the process.

You certainly can run a separate circuit for a trailer mounted battery. You would want to make a separate wiring run from the vehicle battery, using 10 gauge wire and another # 9510 40 amp breaker. You would attach that circuit to the purple wire of the # 37185. You would then have the wire feeding the center pin on the 7-way plug on the trailer connect to the positive trailer battery terminal, with the negative trailer battery terminal being grounded to the trailer frame. Keep in mind that due to the relatively small gauges of wire involved here, your vehicle alternator will not be able to shove enough amperage through to charge a depleted battery. This circuit can however be used to keep the battery maintained, and a charger like the CTEK # CTEK56353 and shore power can be used to fully charge the battery when needed.

expert reply by: Mike L