Can 12 Volt Accessory Circuit of 2019 Ford F-350 Charge Trailer Battery

Question:

I have seen a couple different answers on this question from different experts here, let me clarify..... i have a 2019 f350 with a 7 way trailer plug, i will be towing a gooseneck and would like to charge a spare battery in the tool box for an air compressor and tank. i will be towing full time everyday.. can i connect the aux battery charging wire from the 7 way directly to my spare battery or do i need some sort of maintainer/ conditioner to prevent overcharging/damage to battery/FIRE?? will this interfere with the onboard breakaway charger?? can i leave it connected all the time?? i know the fords will only provide power to the aux/charge wire when a trailer is connected, the truck is on, and the brakes have been cycled

asked by: Nick

Expert Reply:

Running a 10 gauge wire like part # 10-1-1 directly to the battery you have on your trailer would be a great solution to what you are wanting to do. The amperage would be low enough that you'd not need to worry about overcharging or hurting the battery at all. It basically would just keep the battery topped off at all times. Since the circuit on your truck is only active under the circumstances you listed too you wouldn't need to worry about it draining the vehicle battery either. You'd need to tap into the same circuit that's charging the breakaway battery to charge the trailer battery as well.

expert reply by: Jameson C