07-13 Chevy NNBS battery upgrade, H6 to H8.

Buddha.

Lurker
I couldn't find any info online about upgrading the battery so, this is what I came up with.

With the NNBS(07-13?) trucks no matter what gas engine you have, 4.3 to 6.2 your battery choices are either a 615CCA or 730CCA H6(group 48). My truck came with a one year old 615CCA battery that wouldn't start the truck at -33F(this is the first truck I've had in 20 years that wouldn't start in the winter), unacceptable. While it's still warm out I wanted to fix this. I went down the rabbit hole of bigger batteries, AGM, dual batteries etc. I found that even though AGM's claim to have more CCA than FLA I did not find that to be true when I looked at the numbers, also some charging systems may not be compatible with AGM batteries, and they're expensive. As for dual batteries, I'm thinking this large H8 will work instead.
I found that the Dodge 1500 uses a H7 battery, and I found a guy online that upgraded his dodge's H7 to H8. The H8 isn't more expensive than a H7 or H6. So now H8 is what I'm aiming for, and yes I looked at H9 but it's really not a thing.

I knew it was gonna be a tight fit. The H8 is three inches longer than the H6 but the other dimensions are identical. Major modifications that needed to be done was remove the battery tray and remove the raised portion of the stamping that limits the batteries length. I used a cut-off wheel and a hammer.

First picture shows the modified tray. It's modified both top and bottom.
Second picture shows how much extra room is on the tray now.
Third picture self explanatory.
Fourth picture shows the problem I ran into. The negative battery cable wants to run between the battery and the firewall which moves the whole battery over almost a half inch.
Fifth picture shows how tight it is for space. I'm going to put a new end on my negative battery cable and route the cable over the top of the battery so I can slide the battery away from the coolant overflow tank.


I bought the Batteries Plus battery because I believe it's made by East Penn. Napa has what looks to be the same battery. I didn't go with the NAPA battery because I couldn't figure out their warranty PDF. Batteries plus put it right there in the description, 3 years. The battery cost me $122 after the typical batteries plus discount and core.
 

Attachments

Last edited:

mekcanix

Camper
I love this info. I went the dual battery route in my 09 sierra to power my winch (which is still in the garage waiting for me to build a mount of some kind) and as its been useful for camping as a fully charged battery for back up when the solar doesn't charge my TT dual batteries enough I swap it out and use it as a charging station for the weaker battery. I have found that when it gets cold here in January and February that the new H6 is starting the 5.3 but on those stupid cold Winnipeg winter days it has made me worry a couple of times as it was sloooow to crank. I think I will be following your lead on this one this fall. thanks muchly
 

Buddha.

Lurker
I love this info. I went the dual battery route in my 09 sierra to power my winch (which is still in the garage waiting for me to build a mount of some kind) and as its been useful for camping as a fully charged battery for back up when the solar doesn't charge my TT dual batteries enough I swap it out and use it as a charging station for the weaker battery. I have found that when it gets cold here in January and February that the new H6 is starting the 5.3 but on those stupid cold Winnipeg winter days it has made me worry a couple of times as it was sloooow to crank. I think I will be following your lead on this one this fall. thanks muchly
How did you do your dual battery setup? What kind of battery did you use?
 

Recommended books for Overlanding

Buddha.

Lurker
I
I love this info. I went the dual battery route in my 09 sierra to power my winch (which is still in the garage waiting for me to build a mount of some kind) and as its been useful for camping as a fully charged battery for back up when the solar doesn't charge my TT dual batteries enough I swap it out and use it as a charging station for the weaker battery. I have found that when it gets cold here in January and February that the new H6 is starting the 5.3 but on those stupid cold Winnipeg winter days it has made me worry a couple of times as it was sloooow to crank. I think I will be following your lead on this one this fall. thanks muchly
I forgot to mention that this is for a 2500hd gas engine, but I think the 1500 is the same.
 

mekcanix

Camper
I did a simple 140 amp battery isolator from a store we have called Princess Auto, kinda like Harbor Freight. I am using a AGM battery 24 deep cycle I had in my XJ.
As far as I know most of this is interchangeable within NNBS trucks be it 1500 or 2500
 

Buddha.

Lurker
Finally got the ground terminal changed and everything fits a little better now. Wires where 2guage and 10-12? gauge. I used a hydraulic crimper I bought off amazon, I wasn’t comfortable using my hammer crimper for this critical job.

Getting that marine style terminal on and tightened up was kind of a pain would have been easier if I put it on when the battery was outside the vehicle.



Also some may notice I changed the Batteries Plus battery for a Napa battery. You can read about that here if you like.
 

Attachments

Top