Best wire to run?

JamesDowning

Explorer
I would like to bee battery for the winch and also as a back up to the starter battery. I am looking at this set up the same way you would look at any dual battery set up. Only difference is that the second battery is in the nose cone of the trailer vs the engine bay.

Do I understand you correctly that you want to be able to run your truck's winch from a battery in your trailer?
 

Sock Puppet

Adventurer
So you will be pulling from both batteries at the same time when using the winch? That's very different than a slow charge wire from your primary battery to the trailer battery. I'm not a big fan of this idea because of the length and size of wire that would be required and the potential heat and power loss. A dual set-up under the hood would be much better, and you could still run a 10 ga charging wire to your trailer.
 

adi

Adventurer
Just for consideration, National Luna's install instructions for their dual battery relay, with a battery in the trailer, is to run 2-4 gauge wire.

ETA: Whether or not it is if you decide to bypass the delay and start the engine with all batteries is unknown, just one of their demo setups.
 

scottma

Observer
Just for consideration, National Luna's install instructions for their dual battery relay, with a battery in the trailer, is to run 2-4 gauge wire.

ETA: Whether or not it is if you decide to bypass the delay and start the engine with all batteries is unknown, just one of their demo setups.

I had planned to run 4 awg to the trailer battery. How to I make the jump from the the back of the vehicle to the trailer? I guess I need a plug right. I can't step down to the 7 pin trailer plug can I ?
 

adi

Adventurer
I would use something like that are used for battery or winch quick disconnects.

They provide a very firm connection, but should allow a loose trailer to get a clean disconnect as far as wiring is concerned as long as the vehicle side is mounted firmly.

There is a youtube video I saw recently of a Defender owner using them as a quick jump lead connection to the under seat battery, he did a very thorough explanation of the connectors.

ETA: I would also consider emailing one of the trailer vendors here for their advice as well, as far as wire gauge and connections between vehicle and trailer.
 

MakersTeleMark

Adventurer
I'm currently in the middle of a similar project and am using this:

http://bluesea.com/category/2/productline/docs/329

It allows you, among other important tasks, to combine both batteries for emergency purposes. See the tech. I'm using 2 + 4 gauge with some pretty big fuses.

As for "making the jump" to your trailer battery for high amp applications, take a look as some of these connectors:

http://www.vteworld.com/content/electromech/thru_panel.php

I'm thinking a marine bulkhead connector would suit the task well, or you could just use anderson connectors.

But what do I know, I've got all kinds of things going on: 2 100amp 12v alternators and 2 batteries up front, a 24v slave out the grill, and a 12v D31M blue top in the back. I also am powering a pure sine wave Xantrax inverter for AC loads and a 800w amp for tunes and feeding back into the system with solar.

I would think that an aux battery with an combiner/isolator in the engine bay would be the simplest solution for you and just run some light wiring for charging the trailer battery as suggested above.
 
Last edited:

Paladin

Banned
I would like to use the battery for the winch and also as a back up to the starter battery. I am looking at this set up the same way you would look at any dual battery set up. Only difference is that the second battery is in the nose cone of the trailer vs the engine bay.

I think you're over-complicating things.

Do you really need to combine the batteries for winching? Tons of people winch off just the single battery, with no problems. What you're suggesting is just... Rube Goldberg-ish.

What size fuse should I use?

500 Amps, for a winch and starting. At that amperage, it's entirely possible to start a fire without blowing the fuse.

The thought was to run the winch off both the main battery in the engine bay as well as the auxillary battery from the trailer.

For that, you're going to need to run something massive like 0 gauge or better, for both the power and ground, and an Anderson Connector at the back of the truck.

I had planned to run 4 awg to the trailer battery. How to I make the jump from the the back of the vehicle to the trailer? I guess I need a plug right. I can't step down to the 7 pin trailer plug can I ?

4 won't be nearly big enough to run a winch. Especially not over the 20 foot distance you need. And doing it over a 7 pin plug will melt.

Why not just do the simple solution? Do a standard 10ga/7 pin trailer setup. Install a big Group 31 battery in your truck. Carry jumper cables. A good primary battery is plenty good enough to run a winch. In the extremely rare case you need a jump start, remove the trailer battery, bring it up to the front of the truck, and use the jumper cables. This is the slightly slower, but WAY more reasonable approach to this problem.
 

Forum statistics

Threads
185,821
Messages
2,878,586
Members
225,378
Latest member
norcalmaier
Top