Aux Battery Delete

[DDSmith]

So, I understand by reading the posts on these forms that having a bad Aux battery will cause a lot of weird electrical issues. If I delete the Aux battery by pulling the #42 fuse and neg cable. Will the electronic issues be resolved. Things like intermittent door locks not working or, radio controls not working? Or would it be best to simply replace the Aux battery…

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[SonofaSeabee]

Have you had starting issues or dead battery(s), or just these electronic issues?

 

[IceBerg]

Replacing the aux battery is very simple. I always recommend people go through the fender to do it. Last time I did it I think it cost $140 for the battery just be sure you keep the posts off the original battery.

I totally understand people's frustration with the ESS system in the jeep and wanting to delete it to save money is good enough reason for most. But there's no need to delete unless you are having other issues, wanting to save some cash, or looking to do something different in the future.

 

[DDSmith]

Have you had starting issues or dead battery(s), or just these electronic issues?

Just electronic issues but also intermittent issues with start stop

 

[jludave]

If I delete the Aux battery by pulling the #42 fuse and neg cable. Will the electronic issues be resolved. Things like intermittent door locks not working or, radio controls not working?

Have your main battery checked. If your aux is bad, it will take the main with it.

I always recommend bypassing the aux battery and replacing the main with an H7. Once you do so, the vehicle will run just as any other vehicle does with a single battery. Myself and many others have done this and driven many miles without issue.

 

[garyji]

OP, are you on OEM batteries on a 2018??? Change them both ASAP. Don't even bother with any more "homework"!!

G.

 

[Reinen]

If your Aux battery is bad, your Main is at best almost bad. And vice-versa.
Always change both at the same time.

I always recommend bypassing the aux battery and replacing the main with an H7. Once you do so, the vehicle will run just as any other vehicle does with a single battery. Myself and many others have done this and driven many miles without issue.

That may be true but when your Main eventually goes you will have no warnings before you are stranded. Warnings like the OP is experiencing right now which will allow battery replacement before getting stranded.

The Aux battery delete is a question of whether you prefer to control your destiny or let your destiny control you.

 

[jludave]

That may be true but when your Main eventually goes you will have no warnings before you are stranded. Warnings like the OP is experiencing right now which will allow battery replacement before getting stranded.

No different than any other vehicle with a single battery. And there are usually signs a battery is going before it completely dies. I’ve never been left stranded by a failed/dead battery. I’ve always been able to change a bad battery before it fully died.

The dual battery setup on the JL Wrangler is one of, if not the worst of its kind. Other Jeep branded vehicles with the same engines used in the JL run with single batteries and have substantially fewer issues.

 

[GtX]

The Aux battery delete is a question of whether you prefer to control your destiny or let your destiny control you.

Oh my God! How did I manage for 20 years without a little lawn mower battery to monitor my starting battery and tell me when it was feeling ill?

I deleted that thing and reliability is way better in my rig. I'll leave the lawn mower battery in my lawn mower.

 

[Mguy]

. . . when your Main eventually goes you will have no warnings before you are stranded. . . . The Aux battery delete is a question of whether you prefer to control your destiny or let your destiny control you.

ESS operation, which does have the predictive and diagnostic side benefits you refer to, remains fully functional and is not affected by the aux battery negative/F42 disconnect. Your gripe is with those who use software/hardware to disable ESS. Those owners who do the disconnect and either most often use, or don't use at all, the dash ESS shut off button, retain the ESS side benefits. Of course, those owners are less likely to need the ESS side benefits because they have a single battery rather than a lousy two dissimilar battery system.

 

[hemiblas]

OP, are you on OEM batteries on a 2018??? Change them both ASAP. Don't even bother with any more "homework"!!

G.

I'm running oem batteries on both my 2018s. I did have to replace the main battery on one. I guess I need to buy some aux batteries.....

 

[Reinen]

ESS operation, which does have the predictive and diagnostic side benefits you refer to, remains fully functional and is not affected by the aux battery negative/F42 disconnect. Your gripe is with those who use software/hardware to disable ESS. Those owners who do the disconnect and either most often use, or don't use at all, the dash ESS shut off button, retain the ESS side benefits. Of course, those owners are less likely to need the ESS side benefits because they have a single battery rather than a lousy two dissimilar battery system.

What's this gripe you're talking about?
Some people can tolerate a Jeep unable to start at a random time, other people can't and want warning signs before something critical fails. What's important is knowing what you're setting yourself up for so you can make your own informed decision.

Some people talk like the Aux battery delete is the panacea to all things electrical. It's not, there are downsides to be aware of that won't show up immediately after the Aux delete. It does work initially, but it also has a strong tendency to make the first sign of failure a critical failure that leaves you stranded.

 

[STW]

Like others have suggested, your weird electrical problems are probably caused by low voltage in both batteries. If one is having voltage problems, the other one will be too. As you figure it out and decide, it's not a bad idea to know what the actual state of your batteries are. I use this device to monitor them and it can help you decide about replacement.
https://antigravitybatteries.com/products/accessories/battery/chargers/bluetooth-tracker-lead-acid/
same device on Amazon:
https://www.amazon.com/Antigravity-...4gNAOrhMVwBEUWpYPIPaxa34IZzMELRMaAlQMEALw_wcB

 

[jludave]

there are downsides to be aware of that won't show up immediately after the Aux delete.

Like what? Please explain how bypassing the aux battery and running with a single battery in the JL Wrangler is any different than running with a single battery in any other vehicle.

You keep talking about first sign of failure being the critical failure of the battery. This is usually NOT the case. My father was a certified master mechanic who owned a repair shop for over 50 years before he recently retired. I worked with/for him many a time. We've seen plenty of vehicles that required a new battery before the battery was completely dead and left the vehicle stranded.

My wife had a 2017 Grand Cherokee. When the battery started going, she received a warning on her dash. I don't recall exactly what the warning was/said, but she definitely had proper advance warning.

 

[Rhinebeck01]

Like what? Please explain how bypassing the aux battery and running with a single battery in the JL Wrangler is any different than running with a single battery in any other vehicle.

You keep talking about first sign of failure being the critical failure of the battery. This is usually NOT the case. My father was a certified master mechanic who owned a repair shop for over 50 years before he recently retired. I worked with/for him many a time. We've seen plenty of vehicles that required a new battery before the battery was completely dead and left the vehicle stranded.

My wife had a 2017 Grand Cherokee. When the battery started going, she received a warning on her dash. I don't recall exactly what the warning was/said, but she definitely had proper advance warning.

The earlier post in this thread saying it makes sense to keep / you should keep the JL's Auxiliary battery in place as an early warning system in regard to a JL/JT's batteries, was laughable at best..

..... It's not worth the time and effort to make any sense of that thought process.

On my 2018 JL, I have been running with just the Main and with the Aux battery bypassed since 2019.
I've driven over 90,000 miles with that set-up. I do believe I probably was the 1st to do the bypass on a JL. My mentor in doing this was @Jebiruph. Thanks again, Jerry!

Running with just the Main on a JL/JT is no different then running with just the Main on an old TJ or JK or any vehicle with one battery... but you @jludave know that as I do.

Reality is, running with just the Main simplifies the 12v system on a JL/JT immensely... Along with that simplification, there is thus, far less change of battery issues / less chance of getting stranded..

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