How to Wire Trailer Battery to Trickle Charge from Tow Vehicle

Question:

hello Im trying to figure out what would need to be done to establish a charge line from my 7 pin trailer wiring to my battery thats connected to my inverter to power my mini fridge as I haul my trailer between the house and campsite. I have it all set up off the battery but obviously it dies rather quick so need to establish a charge line from the 7 way aka truck to the battery. any help would be great. Thanks.

asked by: Alasdair W

Expert Reply:

To set up a charge line for your trailer's battery you will want to use 10 gauge wire # 10-1-1 in however many feet it will take to feed the wire from the trailer battery to either your trailer connector's junction box or directly to the trailer's connector.

If your truck has a 7-way connector, it is likely already wired for 12V power. You can use a circuit tester # PTW2992 to test the pin in the 1 o'clock position to see if it is powered at your truck. If the vehicle-side connector does not have power, you may need to run another length of 10 gauge wire from the connector to a circuit breaker # 38630 and then to the battery. If your vehicle has a factory 7-way but no power at the trailer connector, try checking the owner's manual for the fuse locations and see if the trailer 12v power is missing or blown.

expert reply by: Victoria B