Decommissioned Tahoe PPV: Auxiliary Battery and Its Usage

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jz57

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Most Tahoe PPVs come with auxiliary battery option (Pro Code 6A6, 5W4 or 9C1), which is part of PPV package. Based on GM published electric circuit schematic, auxiliary battery only supplies power to police add-on electric gears which will be installed by an aftermarket upfitter before Tahoe being delivered to police department.

From 2015 - 2020 model, to preserve the primary battery power, the front engine bay installed auxiliary battery is connected to an isolator relay controlled by an ignition signal (Pro Code 5W4). When the engine is NOT running or the engine is cranking, the auxiliary battery supplies electric power to its designated loads without charging; when the engine is running, the isolator relay is closed and the the auxiliary battery connects to primary battery parallelly and gets charging. The isolator relay is located next to the brake vacuum boost.

From 2021 & up, the rear cargo area installed auxiliary battery is connected to an isolator relay controlled by an ignition signal (Pro Code 9C1). The isolator relay is located right above auxiliary battery.

Before a Tahoe PPV is decommissioned and back to civilian version, most police electric gears are removed. So, the auxiliary battery becomes no electric load, stays alone and a heavy cargo on the truck.

After you get your decommissioned Tahoe PPV, how do you deal with that auxiliary battery? Connect it to primary battery parallelly by by-passing the isolator relay or connect some electric devices to the auxiliary battery, like a trailer?

(From 2007 - 2014 Tahoe PPV had its Auxiliary Battery connected to primary battery parallelly without an isolator relay from GM factory (Pro code 6A6), as a matter of factor, both batteries run like one. So this original setup is excluded in this posting.)

Aux Battery_Relay.jpg

2015 - 2020 Aux Battery Isolator Relay Location


Aux_Battery_Relay2.jpg
2021 & Up Aux Battery Isolator Relay Location
 
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Doubeleive

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I run mine in your "excluded" parallel setup, both batteries connected to starter and alternator
there really is no "right way" people do it all different ways just depends on what will work best for you.
for me running in the parallel setup i would have to kill the batteries pretty hard to not be able to get the needed cca's for starting.
 

RooTBeeRthe1st

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I set mine up in parallel.
However, I have an isolator on the negative side of both batteries so that I can run either one individually as I choose. Just have to pop the hood and give it a couple twists.
Which works pretty nice for camping, my secondary battery is an optima yellow top and I have run that thing down pretty low before while listening to the radio shooting in the desert and stuff for hours on end, then just reconnect my primary and disconnect that one and fire it up. Then let it recharge.(usually by itself again because the other battery doesn't need to be charged at 14 and a half volts when it got used to start it once and that was it)

Pic is on my mini truck, but I have the same thing on the Tahoe.
 

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Sparksalot

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I absolutely love having them in both of the twins. I run ham radios in both, and appreciate having the capacity to run extended periods with the engine off.

In thecopcar specifically, I often have 3 radios plus a 45 liter refrigerator. Dual batteries are a must for me.
 
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Sparksalot

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I know of TP2 which is for trailering, I forget the other one(s).
It’s 6A6 on thecopcar. That one is purely in parallel. Theothertwin actually has an isolation relay, that was bypassed, bu5 I can’t find the build sheet on it.

I did find a scan of the window sticker for thecopcar though.
 

stocksj

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Most Tahoe PPVs come with auxiliary battery option (5W4), which is part of 9C1 package. Based on GM published electric circuit schematic, auxiliary battery only supplies power to police add-on electric gears which will be installed by an aftermarket upfitter after Tahoe leaving GM factory.

In late year version, to preserve the primary battery power, the auxiliary battery is connected to an isolator relay controlled by an ignition signal. When the engine is NOT running or the engine is cranking, the auxiliary battery supplies electric power to its designated loads without charging; when the engine is running, the isolator relay is closed and the the auxiliary battery connects to primary battery parallelly and gets charging.

Before a Tahoe PPV is decommissioned and back to civilian version, most police electric gears are removed. So, the auxiliary battery becomes no electric load, stays alone and a heavy cargo on the truck.

After you get your decommissioned Tahoe PPV, how do you deal with that auxiliary battery? Connect it to primary battery parallelly by by-passing the isolator relay or connect some electric devices to the auxiliary battery?

(Some 2007 Tahoe PPV had its Auxiliary Battery connected to primary battery parallelly without an isolator relay from GM factory, so both batteries run like one. So this original setup is excluded in this posting.)
Hello, new guy here.
I'm hoping to score a Tahoe PPV this weekend at the local auction. One use of the 2nd battery would be a power source for Ham radio or other type of radio comms. At least that's my plan if I win what I want. Thanks, Jim KK4CWO
 

Sparksalot

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Hello, new guy here.
I'm hoping to score a Tahoe PPV this weekend at the local auction. One use of the 2nd battery would be a power source for Ham radio or other type of radio comms. At least that's my plan if I win what I want. Thanks, Jim KK4CWO
Where are you located?
 
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jz57

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5W4 is the RPO code for a 4 wheel drive SSV and is not a battery option code?
It’s 6A6 on thecopcar. That one is purely in parallel. Theothertwin actually has an isolation relay, that was bypassed, bu5 I can’t find the build sheet on it.

For 6A6 (DUAL CRANKING 730 CCA BATTERIES), it is dual batteries setting with parallel connection without isolator relay in 2007 model.

5W4 (IDENTIFIER FOR SPECIAL SERVICE VEHICLE) is a Pro Code for police option package, which includes following options:

(K47) high-capacity air cleaner,
(KW7) 170 amps high output alternator,

(K4B) 730 cold-cranking amp auxiliary battery, electrical power and vehicle signals for customer connection located at the center front floor, auxiliary
battery circuit for customer connection located in the rear cargo area,


(UN9) radio suppression package,
(NZZ) underbody shield, delete roof rails,
(ATD) third row seat delete and
(NQH) active 2-speed transfer case.
 

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