Adding a 12v feed

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Hi all. I have an 89 S10 that will be towing our Trillium 4500. I want to add a 12v feed from my truck to the trailer to run the fridge while we are driving. What guage wire should I run from the battery? Not sure if a fuse or fusible link is the best choice for protection at the battery. I'm also going to run a separate ground and use a two prong type connector to join my power and ground wires to the trailers positive and negative wires. There is a battery box on the tounge of the trailer. The trailer's 12v feed is connected to this battery. Can I just run two more wires off the battery to my 12v feed from the truck so that I am also charging the battery while I drive? Hope this isnt too confusing to understand!
Thanks
Todd

[Legacy Posts]

Todd,

I would use 10ga run all the way to the battery. I used a 20amp fuse at the battery. Most use a resettable circuit breaker instead of a fuse. It is best but didn't have one when I installed mine.

[Legacy Posts]

I'd use 10ga wire also (30 amp rated). Obviously it's also heavier, better insulation and more rugged/durable.

12ga = 20amp

14ga = 15 amp

[Legacy Posts]

I would also add a battery isolator. That way when the tow vehicle is shut off the trailer battery is disconnected. Just in case you park and forget the frig is on. It may still run down the trailer battery, but you'll be able to start the tow vehicle.

[Legacy Posts]

10ga 'stranded' wire. Well, we knew that?!

Casita recommends a resettable circuit breaker (that's what they install) but an inline 20amp fuse sould work fine...

....placed near EACH battery. Ya don't want an unfused line running from either battery thru the tow vehicle! :)
<img src=http://www.fiberglassrv.com/board/uploads/3edbc447b0e9bCasita battery on hitch fuse.jpg/>

[Legacy Posts]

Thanks guys- never thought about the fuse at the trailer battery-thats just plain common sense! Thanks again!
Todd

[Legacy Posts]

Hey, Todd - double check your wiring on that S-10. You should have a red wire running from the junction on the firewall back to the trailer hitch area. It likely won't be connected at that end, but the wire should be there. There should also be a purple or blue (can't remember) wire tied along with it.