How to make a cheap isolated dual-battery setup for $50

[4RunAmok]

Thanks. That helps and clears up a lot. Then would I be wiring the winch off the house or starting battery. Same with the LEDs that would be used while driving? Also looks like the original post is the way to go for me as you pointed out.


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Generally, if the accessory will only be operational during vehicle operation, I can run it from either battery, and will use whichever is easier. But if the accessory will be operational while the vehicle is not running, I will ONLY run it from the AUX battery, protecting the starting battery from discharge.

Another thing to remember is not to mix battery types. Stick with one. AGM with AGM, or Flooded Cell with Flooded Cell. They have different charge rates/requirements, and can run the risk of overcharging the AGM since the Flooded Cell takes longer to charge.

Winches should be attached to the closest battery. The shorter the run, the better. This way you get less voltage loss, and since most winch installs are without fuses or breakers, the shorter the wire, the less chance of mishap. It's always a good idea to protect these wires with split-loom and zip ties to keep them from rubbing against corners and moving objects.

 

[sfsmedic]

Now to figure out what batteries and placement. I was thinking one in stock location of course and the other in the bed in a battery box. I really don't want anymore extra weight up front as my front end is pretty heavy as it is with my bumper and winch. So why add to it.


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[dlichterman]

Now to figure out what batteries and placement. I was thinking one in stock location of course and the other in the bed in a battery box. I really don't want anymore extra weight up front as my front end is pretty heavy as it is with my bumper and winch. So why add to it.

I ended up going with a jegs racing box since it was the only metal one I could find for a group 27 - they also have a 24 sized one too: http://www.jegs.com/i/JEGS+Performance+Products/555/10282/10002/-1

Figured if it was ok for racing, it's probably ok for offroading.

 

[sfsmedic]

I ended up going with a jegs racing box since it was the only metal one I could find for a group 27 - they also have a 24 sized one too: http://www.jegs.com/i/JEGS+Performance+Products/555/10282/10002/-1

Figured if it was ok for racing, it's probably ok for offroading.

Where did you put the battery?


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[dlichterman]

Where did you put the battery?

Front drivers side corner of the bed:

Allthread is through the bed, secured with nylocks on both sides, isn't going anywhere.

 

[sfsmedic]

Front drivers side corner of the bed:

Allthread is through the bed, secured with nylocks on both sides, isn't going anywhere.

That's what I was thinking.


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[dlichterman]

That's what I was thinking.

I'm just down in San Marcos - we met way back on a Cleghorn run with Nwoods - if you want to see my setup or need a hand let me know. I also can't recommend this crimper from HF enough - makes crimping large gauge wires really easy:

http://www.harborfreight.com/hydraulic-wire-crimping-tool-66150.html

 

[sfsmedic]

I'm just down in San Marcos - we met way back on a Cleghorn run with Nwoods - if you want to see my setup or need a hand let me know. I also can't recommend this crimper from HF enough - makes crimping large gauge wires really easy:

http://www.harborfreight.com/hydraulic-wire-crimping-tool-66150.html

Appreciate it.


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[bdog1]

On the subject of winches: I feel the best battery to use is the engine/main battery. This is the battery better designed for heavy discharge and large loads. A deep cycle typical "house" battery will do a poor job here. Having said this, a front mounted winch will typically be closer to the main battery anyhow.


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[3cTactical]

Another thing to remember is not to mix battery types. Stick with one. AGM with AGM, or Flooded Cell with Flooded Cell. They have different charge rates/requirements, and can run the risk of overcharging the AGM since the Flooded Cell takes longer to charge.

Quick question - and maybe I missed it somewhere along the line, but let's say I am running an AGM (Die Hard Platinum) as my starting battery, but I want to run 2 - 6v golf cart batteries as my house batteries due to price and capacity being a better fit for my needs. Is this a bad idea?

 

[kjp1969]

We run two 6v golf cart batteries in our camping trailer with great results. They are cheap and have huge capacity. The downside is that they are huge and weigh a ton.

 

[4RunAmok]

Quick question - and maybe I missed it somewhere along the line, but let's say I am running an AGM (Die Hard Platinum) as my starting battery, but I want to run 2 - 6v golf cart batteries as my house batteries due to price and capacity being a better fit for my needs. Is this a bad idea?

Since you will be wiring your two Golf Cart Batteries in SERIES, making them act as one 12 volt battery, as long as they are AGM batteries, you will be fine.

 

[3cTactical]

Since you will be wiring your two Golf Cart Batteries in SERIES, making them act as one 12 volt battery, as long as they are AGM batteries, you will be fine.

Ok, so just to be clear, this means (for example) I shouldn't use 2 Trojan T105s (I believe these are flooded cell) as my house batts when my starting battery is a Die Hard Platinum?

Or, put the other way around, if I want to use the Trojan T105s as my house batteries, then I should use a standard flooded cell battery as my starting battery?

 

[IdahoXJ]

This has been a great thread and I appreciate the input and ideas.

I want to throw out another related issue. I want to eliminate the A/C equipment in my 89 XJ (it doesn't work anyway and I don't need/want A/C in this rig ... it is not a daily driver). I already have an on-board air setup that does the job so I'm not interested in setting up a belt driven air compressor. Would there be any appreciable advantage and would it be worthwhile to use a dual alternator ... the stock alternator and a new one in place of the A/C unit? I absolutely want to do the dual battery to run my 12V cooler and other accessories while camping. As you can probably tell, I'm fairly ignorant about such issues.

 

[bicyclist]

I've been looking at 20 ft 4 ga jumper cable for wiring up a dual battery system and the inexpensive stuff is copper coated aluminum. Any thoughts pro or con about using it?