Secondary/Auxiliary Battery Setup

[O_jaramillo91]

I was wondering if anyone has the parts numbers for installing a second battery in a 2015 Sierra SLT. I want to use original parts just because personal preference although I know I could probably do it with local shop parts. 

[Eliot]

Same for me!!!!!

[Z2Z]

I didnt realize that there was an OEM solution for this. I'd be interested in a parts list as well.

[O_jaramillo91]

I’m probably wrong but i assume you’d be able to use the same parts as the bigger size trucks that require both batteries. 

[aseibel]

Some older info here, but useful nonetheless. I can't vouch for the current part numbers listed in the article, but this should help. I installed a dual battery in my old truck without an isolator and it worked fine for years. but this new technology is a bit beyond me.

 

https://www.hardworkingtrucks.com/gm-1500-dual-battery-install/

 

https://www.plowsite.com/threads/dual-battery-install-instructions-for-a-chevy.56715/

[Nasty]

This is a modification that people think way to much about. Just get the battery hold down for the second battery spot. And make your own wire runs. Its super easy. I did this in my nbs audio truck years ago and it's still fine

[Nasty]

This is it

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[bndawgs]

Someone on here outlined how he did it in his build thread.  Of course I can't remember who it was.  He was in NC and had a tungsten ltz with a topper though 

[caskey_b]

wouldn't it be as simple as hooking up another battery in PARALLEL with the original battery?   or is there more involved?

 

[sdeeter19555]

wouldn't it be as simple as hooking up another battery in PARALLEL with the original battery?   or is there more involved?
 

Some owners want to isolate the second battery for a reserve...think camper.

But yes, the $1500 I was quoted by the dealer was rediculous and was only Duramax parts, which is a parallel setup. I did the same thing for $350 including the battery and custom cables.

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[bndawgs]

 

[aseibel]

1 hour ago, sdeeter19555 said:

But yes, the $1500 I was quoted by the dealer was rediculous and was only Duramax parts, which is a parallel setup. I did the same thing for $350 including the battery and custom cables.

I bought a battery and some cables from my local farm/auto store and did it for less than that on my 1998. But that was too long ago to remember exactly what the cables cost me. Something like this: https://www.fleetfarm.com/detail/deka-commercial-duty-battery-cable/0000000038129?Ntt=heavy duty battery cable

[sdeeter19555]

I bought a battery and some cables from my local farm/auto store and did it for less than that on my 1998. But that was too long ago to remember exactly what the cables cost me. Something like this: https://www.fleetfarm.com/detail/deka-commercial-duty-battery-cable/0000000038129?Ntt=heavy duty battery cable

I had #00 cables made that are similar to OE because of that long run, complete with swedged ends and custom length. The battery cost nearly $200 alone...I went with a Deka, bought the truck 5.5 years ago and the batteries are still going strong.

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[aseibel]

Key thing to remember when hooking up batteries in parallel is that if one goes bad, it will drain the other one. its wise to put two new ones in together.

[louiecr]