Correct Pin on 7-Way to Wire Trailer Battery for Maintenance Charge

Updated 04/01/2019 | Published 03/30/2019

Products Featured in This Question

Pollak Replacement 7-Pole, RV-Style Trailer Connector Socket - Vehicle End

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10 Gauge Wire - Blue Primary - Per Foot

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NOCO Genius Smart Battery Charger - AC to DC - 6V/12V - 10 Amp

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40 Amp In-Line Circuit Breaker - Perpendicular Mount Bracket

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Question:

Where to I put the wire to charge a battery on the travel trailer Do I put it on the auxiliary plug

asked by: Tim W

Expert Reply:

To provide a maintenance charge to the battery on your trailer while you travel you will want to run the hot lead from the battery to the 12V pin on the 7-Way. At the back of your trailer's 7-Way this will be at the 1 o'clock position (see attached image).

You will also want to make sure that the corresponding pin on the vehicle's 7-Way is active. If not you will just need to run 10 gauge wiring like # 10-1-1 (sold by the foot) from the 7-Way up to the truck's battery via a circuit breaker like # 9510.

Just keep in mind that wiring up the battery this way will do a nice job of providing a maintenance charge while towing but it won't send quite enough power back to actually charge up a depleted battery. To charge up the battery you will want to use a standard AC charger like the NOCO # 329-GENIUS10.

expert reply by: Chris R