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Dual or Aux battery systems


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Feb 4, 2002
Buffalo NY
Has anyone set up a dual battery system for their AV. If so, How.
While installing my electric brake controller (very easy thanks to the suggestion here at CAFCNA to get the prewired harness - just plugged into the AV and the controller) I noticed that on the wiring block under the dash there is an empty area labeled Aux Battery.

Does anyone know if GM/Chevy offers an Aux Battery kit? I would love to ad a second battery, but like stock wiring. The kit from Wrangler NW talked about in this form looks nice, but if I can get a factory kit even better.

Cheers - Jim
While the availability of an auxillary battery kit is certainly possible, I would imagine that the presence of the Aux Battery area under the dash exists because many components in the Avalanche are used in the Silverados and Suburbans as well. I believe that when equipped with a diesel engine, an auxillary battery is almost always present. (My experience with diesels is primarily limited to my parents' '82 Toronado though.)

Just my two cents.
You have a spot for the AUX battery - goes where the fender brace is on the passenger side by the firewall - I really suggest you consider this article Wrangler Dual Battery Kit - far superior to the factory option in terms of control.
Boar-Ral said:
?I believe that when equipped with a diesel engine, an auxillary battery is almost always present.

You are right, Boar-Ral. Diesels require much more cranking power from the batteries due to the very high compression ratios they have.

I'm with you, G! I was not impressed with the factory dual battery option on my Sierra. There was no way to isolate and/or choose which (or both) battery you are using. I wish GM had used a set-up with a salisbury.
Yea Dude, that's where it goes. You can find the whole kit here:


I know of one other member that has done this already. He posted pix a while back. Search for it. He did a cool job on custom mounting the switch under the onstar.
throwin those parties!!carrerarod thanks for the info, i,m gonna call the 800 # tomorrow.... i mounted toggle under cig lighter on the flat area off to 1 side( for the aircraft landing lights in my grill) keep on avn, be careful throwin those PARTIES!!
Sorry to be such a girl, but...
what are the advantages of the second battery? Do you hook up all your accessories to one? If I hooked all my neons up to one, could I leave the truck off with them on for a long time? You still have to link the two batteries to each other or the alternator or what ever so they both charge. I'm (obviously) not sure how this works. Please explain.
Now I am not one to jump right in and start messing around with the electrical system. I have seen the instructions and pics for the wrangler setup, and I know that it would be way to complicated, furthermore I don't know how safe it is to remove the fender/firewall braces on the passengerside, it just seems like it is weakening that whole side. :cautious:
I have talked to some people about this and I think that it is possible to just link the two batteries directly to eachother and have them running together all the time.
You just go positive-positive and negative-negative. I don't know if this is the same as the wrangler, but it seems a little less complicated.
Either way I probably would hire someone to do the job.

-James R. :cool:
The advantage of the Wrangler setup is the ability to isolate the baterries and keep a bad one from preventing you from starting.
jnspur said:
Sorry to be such a girl, but...
what are the advantages of the second battery? ?Do you hook up all your accessories to one? ?If I hooked all my neons up to one, could I leave the truck off with them on for a long time? You still have to link the two batteries to each other or the alternator or what ever so they both charge. ?I'm (obviously) not sure how this works. Please explain.

Yes one advantage would be running all your accessories to the 2nd battery leaving the 1st battery for starting the rig. A cabin mounted switch allows you to select how the batteries get charged and which oen starts the rig.

In addition, replacing the OEM batteries with Optima Yellow Tops would give you even more juice!
jnspur and james 21, i work on boats every day, and dual battery systems are common,,, my 4 add on lights up front can pull over 30 amps, the feed off a seperate fuse from the alternator feed box , left side of the engine.. if i feed them off the second battery, i can leave the original battery for onlly the stock stuff and a batteryISOLATER will charge both batteries, but never let my goodies affect the starting battery.. all i want to do is get home... if one battery is dead, i can use a solenoid between the two, as a"parallel switch"...I am looking for the mount for the battery , i know how im going to wire it!!.. james, i want to leave the brace, especially cause i think it would look,good chrome!!
I would be interested to hear when you find that mounting place. Because I just feel safer having that brace in place. I still want to put a second battery in because I know that I will be adding more lights in the near future when I have my brushguard installed.

-James R.
Thanks for the info, guys, but I think this one is way over my head :rolleyes:
Matt, the owner of the world famous U.A.V. (check for the latest pictures of his red Av appearing soon in a car/truck magazine near you - look for it in American Racing's new ads), and I just completed installation of dual batteries in our Avs.

The kit from Wrangler NW Power Products is great. http://www.wranglernw.com/

The installation isn't too difficult although their instructions aren't very good (the text is OK and the one or two graphics are useless). Don't despair, there are excellent installation instructions available at http://www.off-road.com/chevy/reviews/wranglerdb/

We're now the proud owners of Avs with dual batteries and a great battery management system thanks to Stan and company at Wrangler NW Power Products!


* installation time is about 2 hours if you've done it before. Otherwise figure on 3.
* toughest part of the install - drilling one hole through the firewall. It was a bit trickier on my 2500 than on Matt's 1500 due to different locations of wiring harnesses, HVAC ducts, etc.
* the quality of the kit is great and it's very complete with all the connectors, wires, etc.

Highly recommended - on a scale of one to five Bowties, five being best, I'd give this kit:
:B: :B: :B: :B: :B:
Great and informative post, I am pleased to see that great Av minds think alike, I posted sim experience (somewhat OT) in the 110V inverter mod topic. Helmet posted on this as well, and NYAVALANCHE has one istalled too.

Question for you two: where did you locate the battery manager switch? Mine is inside my Center Console storage bin, against the front side.
Hey JackAl >:D

I installed my switch by drilling into the exposed steel flange that runs along the base of the knee panel under the steering wheel.

My switch is screwed into the steel flange all the way to the right of the steering wheel close to the side of the center console (it's in line with the accelerator pedal). I thought about putting it inside the center console storage bin (very clever) but wanted to (a) see the green light and (b) not worry about accidentally hitting it or having someone else hit it when digging through the center console storage bin (and if I couldn't see the green light then I'd be SOL).
chevroletavalanche said:

I didn't take any pics of my dual battery installation but I will. However, the most important pics are in the link I posted to the detailed instructions. There are plenty of small pics and each one can be enlarged by clicking on it.

Great instructions for a great modification. :love:
:cautious:I've finally got my RCD lift installed and was thrilled with the way it turned out. Thanks for your guidance on the topic. Now I'm debating with myself on which way to go for juice...a dual battery setup, the double rectifier,hi-output alternator or both. I've got to power a dual snow plow setup as well as the usual power hungry options already on board. The 105 amp standard alternator on my 2500 Av probly just ain't gonna cut it ! :cautious: Any opinions out there ?
I just installed my Dual Battery system from Wrangler NW.
Great Article that gandolphxx posted, GM Dual Battery, this was very helpful. I will be installing my 700 watts power Inverter next weekend. ;D





NYAVALANCHE did it with 2 yellow tops and it looks hot.