A dumb tow pig trailer wiring question...

[Paul]

Just installed a brake controller and 7 pin connector on my motor home. Gonna use it to pull a 18' trailer.
My question is about the aux wire. If all it is going to do is charge the breakaway battery on the trailer, why should i use a 40 amp circuit breaker? Will a 20 amp fuse do the job?
Iv'e already pulled a 12 gauge wire from the 7 pin to the chassis battery.
@Ron?

 

[shawn]

Yes, but you can use it to do other things. You can tow a camper with your camper and have room to sleep 15 of your closest friends. I ran a 12ga wire on the Jeep and put a 30A fuse on it. It charged the battery on the camping trailer.

By the way, pay attention to the colors and designations on the circuits. All of the plugs I have ever bought have been incorrectly labeled. I think they go off the "RV" wire colors instead of the "utility trailer" wire colors. It doesn't much matter what color the wires are, so long as the circuits end up in the right places.

Trailer Wiring Diagrams | etrailer.com

 

[Paul]

Done deal. 30 amp fuse at the Perko chassis battery disconnect has been installed.

 

[paradisePWoffrd]

I use the 12v wire to charge the winch battery on my trailer, which also powers aux lights for loading/working on your junk.

On a similar note, while you are wiring, put some good Rev lights on the trailer and wire them up. You will be glad, esp pulling with the bus.

 

[upnover]

If I read this right, you are using your 12v Aux to charge or keep charged, the trailer break away battery. If so, with a 12ga wire and a possible discharged trailer battery, you will end up with a blown fuse if it pulls too many amps. The breaker will break, and reset, so eventually it will be able to charge the battery if, it can be recharged. I'd use the breaker.