Dual Battery Setup using OEM parts?

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Bubbaduss

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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.
 
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Tall56Dog

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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.
 

Bubbaduss

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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

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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

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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

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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 :-/

2022-07-25 17.27.33-1.jpg
 
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Tall56Dog

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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.
 
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Tall56Dog

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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.
 

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