in2pro

gabenderthat is the same thing I thought also, just back fed into the sytem via those studs, they do provide power to the accessories when the ignition is off, HOWEVER I don't know if starting power would be pulled back thru that same circuit which could be a bad thing... If you do a forum search for AUX battery there are several topics on the matter but this particular thread seems to have the best info on the addtion of the extra battery

Rodehard

2nd Battery Fundementals:
This is easy guys, don't overthink it. A 2nd battery is used to provide more "Amphours" or "Ampacity". Connected in parallel to the 1st battery, voltage remains the same, alternator charges both, and you can run accys twice as long.

To connect: Run 2 gauge black battery cable from negative #2 battery post to any nearby available engine block bolt. Run a 2 gauge red battery cable from #2 positive battery post to #1 positive battery post. Route battery cables along existing harnesses, and secure with tye wraps (panduit ties). measure first and you can buy premade cables at any auto parts store.

If you must have a "quick-disconnect" to either or both batterries, the most convenient I've found are available from stereo suppliers such as Crutchfield. They attach at the negative post, and require an 1/4 turn, by hand, to connect or disconnect.

Enjoy!!

73shark

Probably should hook #2 + to where the #1 +cable hooks to the starter as GM didn't make it easy with their new lashup for the battery. Also one problem w/ the straight parallel setup is that both batteries w/ run down together. Maybe w/ two Optimas that wouldn't be a problem, just an expensive solution.

loulblades

Sounds like the newer Tahoes are setup similarto my '96. When I acquired mine it had a storage box in the second battery location. The second battery was an option at the time and I think still is.

I purchased the battery tray from Wrangler Power Products. On mine there were 2 cables on the original battery +, 1 went to the starter and 1 to the fuse box under the hood (1 of the 2 studs).

Since I wanted to isolate my batteries so that if the accessories battery ran down (an Optima Yellow top)I would still have some starting juice, I put an isolator on the passenger side near the starter battery and conneced it using the cable that ran to the box. I thenattached a battery cable from my second battery to the stud. The isolation relay closes when the alternator puts out ~13.4 volts. I also put a breaker between the isolator and the second battery.

Works great so far.

one55alamo

Does anyone know who/where I might obtain a pre-made, Factory type battery tray for that passenger side spot, where the bracket meets the fender? I checked with the local GM dealer, and they dont know what I am talking about. I have an aftermarket tray, but am looking for a cleaner looking install. As it stands, the battery has to be a little smaller by my measurements to mount under that bracket. Any ideas?

yarom

Last time I checked, these parts were in the the law enforcment version of the Tahoe and I managed to find a PDF that listed the option - option 6A6, dual cranking 730CCA batteries.

Please share if you figure out anything...

4wd

Interesting..Any updates? pictures?

Thanks

Hardin Thicke

Here's my auxiliary battery project with pictures:

https://chevroletforum.com/forum/tahoe-suburban-25/auxilliary-battery-install-project-22289/

Glockski

My police package tahoe has two batteries. One where yours is and the other is where your empty tray is.

in2pro

This is how I set mine up...

The blue circled fuse is the cable running to the 12v for the trailer harness, it provides fused 12v to your trailer battery via the 7pin connector.

The other fuse connection runs directly to my Aux battery ( deep cycle) for my trailer/camper. ( I use the tray to charge/maintain the battery when not on the trailer, it also provides added accessory power to the vehicle when in this position, it however does not provide starting power)

The ground cable is connected at the frame, it is a standard negative battery cable.

The red cable is a 8 gauge stranded copper wire, fused with 30amps it provides charging voltage only, it does back feed into the fuse block and provides extended 12v capacity to the system. i.e. radio, DVD player 12v outlets

Yes both batteries could potentiality be discharged there is no isolator in line.
(I don't need it isolated as its just an alternative way to charge my camper battery when not it use on the camper trailer)

The starting circuit disables this battery automatically when starting so back feeding to the starter is not an issue. ( same reason you radio cuts off when cranking)

The battery was ~$ 62 bucks at Sams, the cables were ~$12 at Pep Boys

I simply disconnect the ground/negative cable to isolate it from the vehicle,
when giving someone a jump start.

Again, it is not isolated, but I do disconnect it from time to time so i know the condition of my main battery, it keeps my camper battery at top charge when not in use....

The wire for the trailer is already there if you have the trailering package, you only need to un-bundle the wire and connect it to the stud.

Both fuses were already in place for the 2 studs.