Can Trailer Running Light Circuit Be Used to Charge a Trailer Breakaway Battery
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Question:
Want to know if it is legal to charge the breakaway battery by utilizing the brown wire for clearance lights that comes thru the harness on the trailer. We run with clearance lights on for safety. We wire the six way plug center lug to a switch for strobe lights that are mounted on the rear of the trailers. As long as the battery is charging it should be alright. YES?
asked by: Bill
Expert Reply:
The running light circuit on your trailer connector, typically a brown wire as you note, is not suitable for charging a breakaway battery. A dedicated 12V auxiliary power feed to your trailer is suitable for maintaining a breakaway battery (but not for charging a depleted one).
It is always best to charge your breakaway battery (and any other on-board 12V trailer batteries) with a dedicated charger like one of the CTEK units, part # CTEK56353 for example, before heading out. Then you can use the 12V auxiliary circuit for maintaining those batteries. While this may be legal in some states we do not recommend it.
You'll notice that the wire gauge use for the running light circuit is lighter gauge than that for a 12V power circuit. Typically a running light circuit is carried on 14-gauge wire while a 12V feed is on a 10-gauge wire.

Product Page this Question was Asked From
Hopkins Engager Trailer Breakaway Kit w/ Charger, LED Tester, and 5 Ah Battery - Side Load
- Trailer Breakaway Kit
- Kit with Charger
- Side Load
- Single-axle
- Tandem-axle
- LED Tester
- Hopkins
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