Dual Battery Setup using OEM parts?

[Bubbaduss]

My goal is to power a 12v mini fridge (about 8 amps when the compressor is running) in the back without killing my starter battery. I'm driving around every day, so long sits are never an issue. Mostly the summer heat doing inspections, I end up drinking 4-6 bottles of water a day. And it's nice to keep my lunch cool, or for trips with the kids and whatnot.

 

[Tiki]

Great write up OP

 

[Tall56Dog]

My tray is exactly that #... I had to install the battery hold down block before putting the tray back in as there didn't appear to be any threaded receiving point...

I have questions regarding the battery side of things.

What did you change on this box? If anything

View attachment 375719
View attachment 375720

Sounds like you figured a way to make the existing battery tray work, but if it didn't have a threaded hole, it was most likely the stock tray. They look very similar, not sure why GM just didn't use the same tray that would work for both.


On the vehicle battery side of things, it's actually kind of neat, you'll see when you get the new cable assembly. It comes with a connection that just plugs in to the side of that plastic fuse assembly on top of the battery. That way, it's actually a quick disconnect fused connection for the Aux battery.

 

[Tall56Dog]

Great write up OP

Thanks!

 

[Bubbaduss]

Sounds like you figured a way to make the existing battery tray work, but if it didn't have a threaded hole, it was most likely the stock tray. They look very similar, not sure why GM just didn't use the same tray that would work for both.


On the vehicle battery side of things, it's actually kind of neat, you'll see when you get the new cable assembly. It comes with a connection that just plugs in to the side of that plastic fuse assembly on top of the battery. That way, it's actually a quick disconnect fused connection for the Aux battery.

I've learned a lot doing this and I'll add a great deal to your write up. But definitely a big thanks for the guidance.

I know you skipped the OE relay and isolator. Is that because you don't have the plug that connects to it?

I have everything in place and have found I'm missing the dongle to actually signal the isolator relay.

 

[Bubbaduss]

The correct part number for the battery tray is

22989633​

23231841c is what comes standard and does not have the correct provisioning for the battery.

 

[Chickensandwich]

I have a dual battery set up but I’ll be damned if I know how to use it so I don’t kill my main battery…

 

[Bubbaduss]

Anybody know what this harness partners with?

has a "PBT GF20" molded into it, but google seems to disagree.

This is in the positive battery live to activate the relay, that activates the isolator...
rumor has it, it partners with a harness that is blocked off by the primary battery, yet it appears to be absent on my truck.

so the next task is to find the signal pinout in the box and make my own connector.
This is where the Keyline VSR is the better choice :-/

 

[Tall56Dog]

I've learned a lot doing this and I'll add a great deal to your write up. But definitely a big thanks for the guidance.

I know you skipped the OE relay and isolator. Is that because you don't have the plug that connects to it?

I have everything in place and have found I'm missing the dongle to actually signal the isolator relay.

Yes, my 2020 didn't have the wiring connection for the relay. I just removed the relay and wiring from the harness and replaced it with the Keyline VSR. It does the same thing as the relay only electronically.

 

[Tall56Dog]

Anybody know what this harness partners with?

has a "PBT GF20" molded into it, but google seems to disagree.

This is in the positive battery live to activate the relay, that activates the isolator...
rumor has it, it partners with a harness that is blocked off by the primary battery, yet it appears to be absent on my truck.

so the next task is to find the signal pinout in the box and make my own connector.
This is where the Keyline VSR is the better choice :-/

View attachment 376368

On my 2020 Tahoe, there was no connection for this. I just replaced this relay with the Keyline VSR.

 

[thedenalitraveler]

Thanks for the writeup! I'm planning to take on this project for my 2016 GMC Yukon Denali and I wanted to ask what battery you all used. I realized that my primary battery in the truck is a H7, and it looks like the Aux tray can only fit a H6 (I'm not sure if the part number provided earlier changes the size of the battery it can handle as well. Please let me know!

 

[Doubeleive]

Thanks for the writeup! I'm planning to take on this project for my 2016 GMC Yukon Denali and I wanted to ask what battery you all used. I realized that my primary battery in the truck is a H7, and it looks like the Aux tray can only fit a H6 (I'm not sure if the part number provided earlier changes the size of the battery it can handle as well. Please let me know!

both batteries should match, same make/type and they should be the same age, using a older battery and new one is not advisable
if yours is a H7 then the spare tray should hold one as well, they haven't changed the battery holder design in a long time, they have changed from side post to top post and the main battery positive fuse design has changed a couple times but that won't matter on the 2nd battery

 

[thedenalitraveler]

I agree that both batteries should match, in my 2008 Yukon, I used 2 H6 batteries connected in parallel - and that was fine. The issue here is that for some reason in the 2016 Yukon, the main battery is a H7, but the aux tray fits a H6 only (an H7 wouldn't fit, it is too wide for the tray).

In your trucks, did the main battery come as a H6 or a H7?

 

[Doubeleive]

I agree that both batteries should match, in my 2008 Yukon, I used 2 H6 batteries connected in parallel - and that was fine. The issue here is that for some reason in the 2016 Yukon, the main battery is a H7, but the aux tray fits a H6 only (an H7 wouldn't fit, it is too wide for the tray).

In your trucks, did the main battery come as a H6 or a H7?

I only have the dual setup in the 2012 which are h6, the 18 is a h7 they have k2xx ppv suv's and pickup's so there must be a different tray then if this is the case or modify the tray so it will fit the battery, the rubber hold down is the same part since like waaaay back

 

[Doubeleive]

I looked on rockauto they only have the right side, what you may need is the last 8 of the vin for a k2xx ppv, then you can call the dealer parts department and inquire about the left side battery tray part number

 

[thedenalitraveler]

I actually did some research here, it seems like the PPV's run mixed batteries in the newer models. I pulled the specifications from GM for the 2022 PPV's and it seems like they run a H7 primary with a H6 Auxiliary.

• 900 cold-cranking amps primary battery
• 760 cold-cranking amps auxiliary battery with 70-amp hour rating

The battery tray is part 22989633 (which is the same for your truck too). The question here is how the PPV's can run a mixed set of batteries without draining down the primary battery, or causing overcharging to occur. I can think that the only way they do this is through a battery isolator of some sort. Any thoughts?

Most of my electronics are running on the main circuit, which leads to my desire to run parallel batteries without the isolator - as my understanding is, if I used a battery isolator, I would need to wire a specifically separate circuit from the aux battery - otherwise if I run them from the main circuit in the car, it would draw on the main battery only, and not from the Aux battery with the engine off. Please correct me if my understanding is wrong.

Thanks in advance!

 

[Sparksalot]

I actually did some research here, it seems like the PPV's run mixed batteries in the newer models. I pulled the specifications from GM for the 2022 PPV's and it seems like they run a H7 primary with a H6 Auxiliary.

• 900 cold-cranking amps primary battery
• 760 cold-cranking amps auxiliary battery with 70-amp hour rating

The battery tray is part 22989633 (which is the same for your truck too). The question here is how the PPV's can run a mixed set of batteries without draining down the primary battery, or causing overcharging to occur. I can think that the only way they do this is through a battery isolator of some sort. Any thoughts?

Most of my electronics are running on the main circuit, which leads to my desire to run parallel batteries without the isolator - as my understanding is, if I used a battery isolator, I would need to wire a specifically separate circuit from the aux battery - otherwise if I run them from the main circuit in the car, it would draw on the main battery only, and not from the Aux battery with the engine off. Please correct me if my understanding is wrong.

Thanks in advance!

@Chickensandwich how is your PPV setup for batteries? On both thecopcar and theothertwin, gmt900s, the batteries were identical H6s. For thecopcar the were not isolated at all. in theothertwin the had an isolation relay, but it had been bypassed at some point after delivery.

 

[thedenalitraveler]

@Chickensandwich how is your PPV setup for batteries? On both thecopcar and theothertwin, gmt900s, the batteries were identical H6s. For thecopcar the were not isolated at all. in theothertwin the had an isolation relay, but it had been bypassed at some point after delivery.

On my GMT900 Yukon (a 2008 Denali), they were dual H6's - so I installed them without isolation and it works fine. I'd be curious to see how the new K2xx PPV's are set up.

 

[Doubeleive]

I actually did some research here, it seems like the PPV's run mixed batteries in the newer models. I pulled the specifications from GM for the 2022 PPV's and it seems like they run a H7 primary with a H6 Auxiliary.

• 900 cold-cranking amps primary battery
• 760 cold-cranking amps auxiliary battery with 70-amp hour rating

The battery tray is part 22989633 (which is the same for your truck too). The question here is how the PPV's can run a mixed set of batteries without draining down the primary battery, or causing overcharging to occur. I can think that the only way they do this is through a battery isolator of some sort. Any thoughts?

Most of my electronics are running on the main circuit, which leads to my desire to run parallel batteries without the isolator - as my understanding is, if I used a battery isolator, I would need to wire a specifically separate circuit from the aux battery - otherwise if I run them from the main circuit in the car, it would draw on the main battery only, and not from the Aux battery with the engine off. Please correct me if my understanding is wrong.

Thanks in advance!

I haven't seen the setup for 2 batteries on the k2's, there are isolator's that will automatically draw on the 2nd battery if the 1st becomes to low
the gm upfitter guide may have detailed information on that

 

[Tall56Dog]

Thanks for the writeup! I'm planning to take on this project for my 2016 GMC Yukon Denali and I wanted to ask what battery you all used. I realized that my primary battery in the truck is a H7, and it looks like the Aux tray can only fit a H6 (I'm not sure if the part number provided earlier changes the size of the battery it can handle as well. Please let me know!

This is what I used for the Aux battery.

https://www.interstatebatteries.com/products/mtx-48/h6/2020-chevrolet-tahoe-v853l

In my 2020 Tahoe, the starting battery is an H7, but the Aux is an H6. An H7 won't fit in the Aux battery tray.

The batteries don't need to match if you're running a VSR, the VSR only sends power from the alternator to charge the Aux battery when the starting battery is above a certain voltage. And keep in mind that with this setup, the Aux battery doesn't help start the vehicle, only provide power to the accessories you have hooked up to it.