I've got a 1989 22' bumper pull trailer. its an oldie, but for the most part works fine. I have been messing around with adding a second 12v batt & noticed that there are 3 wires that are supposed to be hooked up.

Qty 1 16ga positive wire

Qty 1 16ga negative wire

Qty 1 18 or 20ga positive wire

So, obviously the 2 16ga wires are for the main power to the inverter/trailer, but I was wondering what the smaller 12v + lead was for.

Anybody know? Why would there be 2 positive leads for the battery terminals.

 

It's probably for the breakaway switch. Power should be ran to it directly from the battery.

 

good point. never considered that.

thanks!

 

Could go to the propane detector too. They like to wire those straight to the battery.

 

Not sure if my trailer has one....it is 20+ yrs old.

 

Sounds like awful light wiring to me. What loads does it carry ?? I'd think seriously about up-grading it.

Lar.

 

the entire trailer does not draw that many amps-12ga is more than sufficient-according to my electricians at work here

 

I had an 84 model Fleetwood that had one.

 

If you have a 2 or 3-way fridge, you would have a positive lead going to the refrigerator. As for the main power cables from the battery, I wouldn`t use anything smaller than #12 gauge. The smaller the wire, the more voltage drop you will have.

 

Mine is set up with 2 positive wires. The thicker one goes to the power distribution box and the seperate converter/charger.

The thinner one runs directly to the stereo, apparently to reduce "noise".

 

Mine is setup with 2 - 10ga. wires running from the batteries to the power distribution center to allow for 30amps of current draw. Then there are 2 - 6ga. wires that go from the batteries to the converter/charger. The convertor/charger is a 55amp model.

 

I agree that it is most likely for the brakes breakaway switch.