Can Breakaway Battery on Trailer be Charged Using Running Light Circuit

Published 08/08/2014

Products Featured in This Question

12 Gauge Wire - Black Primary - Per Foot

(30)

$2.08

Pollak Circuit Breaker - Cycling/Automatic Reset - 40 Amp - Straight Mount Bracket

(49)

$7.70

Question:

Do you see a problem with drawing power from the brown side light wire when installing the breakaway system? My tow vehicle was not wired to supply independent 12v power via the black connector on the 7-blade plug. Jumping a wire in the trailer junction box from the side light circuit to the breakaway charger should provide 12v power to charge the battery whenever the headlights are on and would be much easier than running a wire from the vehicle battery to the appropriate connector on the hitch. Are you aware of any negative issues with this plan? You have a great web site BTW. I just received my electric brakes and breakaway kit and everything works great and was a real bargain!

asked by: Dan R

Expert Reply:

Charging a breakaway system battery using the running light circuit on the trailer could work as long as the wire gauge is sufficient and as long as the charger doesn't overdraw the running light circuit which it shouldn't on a small breakaway battery. But any time you start adding things to a circuit there is the potential for something to go wrong.

Ideally you would run the power wire from the battery, through a 40 amp circuit breaker, # PK54540, and to the 7-Way trailer connector using wire # 12-1-1, sold in increments of 1 foot.

expert reply by: Michael H