Parts Needed to Charge Trailer Battery with Shore Power

Published 08/10/2026

Products Featured in This Question

Progressive Dynamics 9300 Series RV Converter Charger - 12V - 45A

(400)

$262.73

10 Gauge Wire - Blue Primary - Per Foot

(109)

$1.61

Question:

I need to add shore power to a dog trailer that has break-away electric brakes system in place. I want to use a full-size auto battery, add shore power and remove the little one. I need a complete wiring diagram and material list. The trailer has 12-volt fans for the dog boxes. We want to add exterior lights for loading and unloading dogs in the dark. We will need on board charger that runs off the 110-shore power circuit to keep battery charged when parked at our hunting lodge for weeks at a time. We also want the truck 7 pin to charge the on-board trailer battery when traveling. I have the ability and proper tools for the job. I operate an auto motive repair shop and fix all electrical systems as needed. We plan to start this project mid-week. Your help would be greatly appreciated. Shooting Stars auto body and repair in Ohio. Thanks

asked by: Kenny G

Expert Reply:

Hey Kenny, I read your question and it actually sounds like you are looking for a way to charge a 12 volt battery with shore power when parked as all of the accessories you want to power are 12 volt. So for that you would need a converter charger like the part # PD69RR which you would run to your battery and it would keep it charged when plugged into shore power.

To allow your 7-way to charge the battery when towing you would just need to run 10 gauge wire like part # 10-1-1 from the 1:00 pin of the 7-way to the positive post of the battery and that would be covered. Is there anything in the trailer that would need to run of AC power?

expert reply by: Jameson C