2000-2006 Suburban 1500-- modify for bigger size 2nd battery?

[Saabologist]

2002 Suburban 1500 Z71

Hi all and thanks for pointers. I want to install a dual battery, which is easy. BUT I really want to use a 100ah AGM battery and can't find one that will fit in either the start battery space or the "house" battery space. Does anyone have a thread or information on modifications to allow the bigger battery to fit?

For several years I carry the 2nd battery in a battery box strapped into the back. I would really like to have it in the engine bay with a simpler battery isolator setup.

Thanks,

 

[ratled]

I have seen some guys put a 2nd battery in the back left corner (as you face the motor). You have to remove the fender brace but thats 2 bolts. Not sure if your battery will fit that space or not. Please post pics of your success

Good luck!
ratled

EDIT: found a picture with this setup on 2002

 

[Buddha.]

2002 Suburban 1500 Z71

Hi all and thanks for pointers. I want to install a dual battery, which is easy. BUT I really want to use a 100ah AGM battery and can't find one that will fit in either the start battery space or the "house" battery space. Does anyone have a thread or information on modifications to allow the bigger battery to fit?

For several years I carry the 2nd battery in a battery box strapped into the back. I would really like to have it in the engine bay with a simpler battery isolator setup.

Thanks,

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

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...

expeditionportal.com

Not sure how much this applies to the earlier trucks but it’s worth a look.

Note:
On your truck the original battery is in the opposite position than the later trucks. My main/original battery is passenger rear position. I was able to modify that tray to hold the bigger battery. Truck starts at -28f now no problem.

 

[Saabologist]

Thanks Buddha, I will see if that will work on my 2002 1500. I made little box the size of my Duracell 100ah deep cycle battery and it looks impossible to fit it into the rear passenger corner of the engine bay where the 2nd battery can be located. I may have located a 80ah battery that could work, but I sure would like 100ah (without spending a ridiculous amount on LiPO4).

More comments welcome please!

 

[Buddha.]

You might have to temporarily remove the air box and coolant overflow tank(or whatever’s over there) in order to slide in the oversized battery.

 

[Burb One]

The passenger rear location is the OEM location for upfit 2nd batteries on GMT800's (and also the same brackets on 2500 silverados, which with the diesel came with 2 batteries and have the same fenders as burbs)

You can find on ebay the battery tray that will bolt in. (does require the removal of the support there. I am able to putt the battery without touching the coolantoverflow tank.)

 

[ratled]

Thanks for that Burb. I found this kit, pricey but its a complete package
https://dirtyparts.com/store/detail.cfm/DUAL-BATTERY-KIT-99-06-CHEV---GMC/pid-80427

This one too that is cheaper
https://www.dfna.info/product/silverado-dual-battery-kit/

 

[Mighty Dodge Ram]

That is indeed the location for the 2nd battery in your rig, it matches the one in my ‘02 Silvy 2500HD. The issue will be size, you don’t have much clearance there, especially height wise. OEM is a Group 78, smaller with side posts. I installed a Group 78 Marine battery in the primary tray (driver‘s front behind the headlight and washer bottle), this battery has top and side posts. I believe the same style of battery will fit in the secondary location but I have not checked the height for clearance yet...install to come. Following...

 

[Burb One]

Thanks for that Burb. I found this kit, pricey but its a complete package
https://dirtyparts.com/store/detail.cfm/DUAL-BATTERY-KIT-99-06-CHEV---GMC/pid-80427

This one too that is cheaper
https://www.dfna.info/product/silverado-dual-battery-kit/

Wow that is $$$ I think I paid 80 bucks for mine on Ebay. Pick and pull... there's million sof 2500HD's I'm assuming the hard thing would be finding one that didn't have battery acid associated rust... though should be easy enough to sand and repaint.

 

[Martinjmpr]

The biggest AGM I was able to find was 68 AH and it was very expensive (around $280 at Batteries +.)

I would think there might be more space to work for in the main battery location (drivers side behind the radiator.) That space up on the passenger side above the fender is very tight. Of course, an AGM can be mounted sideways so that might be a way to go but you' d have to fab something up to hold it in place.

FWIW my 55AH main battery and 68AH house battery with isolator worked great for the 3 years I used it. I had it set up so my fridge ran from the house battery and the one time I left a light on and my main battery was too low to start the truck, all I had to do was keep the ignition on for about 30 seconds for power to flow from the house battery to the main battery and then I was able to start right up.

EDITED TO ADD: I also ran 31/78 batteries at both locations. 31 and 78 are the exact same battery except 31 has top terminals and 78 has side terminals. As you can probably guess, 31/78 has both. That gave me more flexible options in terms of wiring because each battery had a double set of terminals.