Group 31 AGM in JKU - Nitty Gritty Details

[biedron]

I want to install install a group 31 under the hood of my 2018 JKUR (principally to run an ARB 50 qt fridge). I’ve looked all over the interwebs for info. Found the most info here, but I’m still unclear on some details.

I think I understand the needed mods to the stock battery tray to fit the larger group 31 instead of the stock group34 - remove a plastic spacer block at the front of the tray, and grind away some plastic at the rear of the tray.

But then:

1) it seems like the evap purge solenoid near the front of the tray will be in the way (?). If so, how and where to relocate it? I could not find any aftermarket kits for such a relocation.

2) How to mount / secure the group 31 to the battery tray? From what I can tell, the group 31s don’t have the same mounting “foot” that the group 34s have. I’ve seen a couple of suggestions for the Savior Senior Battery Tray and Savior JK Factory Battery Mount. Seems like both would be needed - would the combo add too much height? Are there alternatives to securing a group 31?

3) I think the stock battery has the terminals reversed from a standard group 34. I don’t find group 31s with reversed terminal (maybe one). Seems like this would be a non-issue - just turn the group 31 around to suit? I suppose it is the location of the base “foot” on the group 34 that makes the reverse terminals required on the stock battery?

So bottom line I’m looking for practical tips on the install

Thanks,

Bob

 

[WOODY2]

There is a very large weight difference to be considered.

 

[ratled]

The weight isn't a big issue, I run a pair of grp 34's with the Genesis dual battery kit. If you can afford to do so this is a great a way to go. Yes its more weight but it's a Jeep - we're suppose to over weight them!

As for reversed, the grp 34R batteries have reversed posts from standard ones

 

[Tswhit15]

I run dual batteries in my 2015 JK. I used the rugged ridge dual battery tray which was a real pain in the ass to install. It requires the removal of the old tray which can be tricky and is attached to the base of the airbox and the fuse box and cut and trim both. The purge valve you can simply unplug and bolt it somewhere else. It's got quite a bit of slack if I remember correctly.

 

[biedron]

I run dual batteries in my 2015 JK. I used the rugged ridge dual battery tray which was a real pain in the ass to install. It requires the removal of the old tray which can be tricky and is attached to the base of the airbox and the fuse box and cut and trim both. The purge valve you can simply unplug and bolt it somewhere else. It's got quite a bit of slack if I remember correctly.

Good to know about the purge valve. The arguments in favor of a single larger battery vs two smaller batteries seems to make sense to me, so that is the route I’d like to try.

A group 27 would be a little smaller and so that might be an option, but ~ 15 Ahr less capacity than a group 31 - so appreciate any tips on that size too.

I’ve already got a lithium jump start battery as insurance against draining the single battery.

 

[Tswhit15]

Good to know about the purge valve. The arguments in favor of a single larger battery vs two smaller batteries seems to make sense to me, so that is the route I’d like to try.

A group 27 would be a little smaller and so that might be an option, but ~ 15 Ahr less capacity than a group 31 - so appreciate any tips on that size too.

I’ve already got a lithium jump start battery as insurance against draining the single battery.

Yea I was looking to put in a dual battery system so I could comfortably run lights at night in the roof top tent ect. Plus for insurance when I was far from civilization. I ended up going with the National Luna Isolator and monitor. It's been installed for just over a year and has worked well so far.

 

[biedron]

So I ended up installing a Group 27 (Northstar NSB-AGM27F) instead of a Group 31. Knowing that a Group 27 could be accommodated based on this thread, I futzed around enough to get the purge valve relocated. Without cutting the tubing and re-plumbing, relocating the purge valve is something of an unnatural act At least in a 2018 JKUR, the tubing that leads into the valve is quite stiff, and along with the connectors it is definitely meant to take a 90 degree turn - to relocate the valve you want it so that there is no turn at all. I didn't want to cut any of the lines or do anything else irreversible, but eventually I was able to get it relocated without kinking any of the tubing. I secured the valve to some nearby large wire bundles (which were themselves pretty rigidly anchored) with some zip ties to help hold it in place. Somewhat kludgy though.

Removing the plastic tab at the bottom of the battery tray (super easy) makes the tray dimensions just right for a Group 27 battery (like maybe that was a design intent). But despite the adequate dimensions, is was a bit of a struggle to get the battery down into place because there is not much extra space for maneuvering.

Hopefully the 92 Ah of the Group 27 will be adequate for running an ARB 50 Qt fridge for a few days. I've got a 180 W portable solar panel to recharge and a Noco lithium jump starter as backup.

 

[TacticalBBQ]

Do you have any photos? I been thinking about upgrading my battery in my JK but don’t have the funds for a dual set up. I am also running a ARB 50.

Thanks

 

[biedron]

Here are some photos. I found it helpful to route the tubing behind the dipstick. In the last photo my finger points to where the purge valve was originally mount - clearly no room there anymore.

BTW, the "F" in the battery model NSB-AGM27F is for the reversed terminal orientation used in later model Jeeps, with the positive terminal near the firewall.

 

[MattJ]

Just in case it’s helpful, here are some photos of what the Genesis system looks like installed:

https://www.expeditionportal.com/forum/threads/genesis-dual-battery-system-install-photos.183502/