Aux Batt Died - Replaced it - Both Died - HELP

[Billyg73]

About 2 weeks ago I had a light show when I tried to start the jeep. I replaced the AUX battery and all was well. YEsterday (in the heat) my wife tried to start the jeep and it had nothing. Checked the voltage and it was 5.9V across the batt. pulled the ground to the aux and that was 5.9 also. Managed to charge and jump the jeep but I need some help as to what could have drained the battery to 5.9 volts. I am guessing some parasitic drain or something not turning off properly. I have a Tazor which has been in for 4 months. I plan to do the AUX delete, but want to troubleshoot any drain on this thing. I am going to try to hit the dealer for a new battery as the car is 2.5 yrs old.

THANKS!

Sponsored

 

[Omen]

For a while, my Taser had an issue where it would not let certain electronic devices enter sleep mode. Once a month, I would come out to a dead Jeep that a jump could get running again. I eventually had to pull out the Taser to stop the drain as my luck had the dead battery on a work morning, every time.
I have been updating and watching the release notes for the Taser, and I finally felt comfortable re-installing it. So far, so good...

Moral of my story... make sure your Taser is up to date.

Maybe this helps?

Mike

 

[jludave]

About 2 weeks ago I had a light show when I tried to start the jeep. I replaced the AUX battery and all was well. YEsterday (in the heat) my wife tried to start the jeep and it had nothing. Checked the voltage and it was 5.9V across the batt. pulled the ground to the aux and that was 5.9 also. Managed to charge and jump the jeep but I need some help as to what could have drained the battery to 5.9 volts. I am guessing some parasitic drain or something not turning off properly. I have a Tazor which has been in for 4 months. I plan to do the AUX delete, but want to troubleshoot any drain on this thing. I am going to try to hit the dealer for a new battery as the car is 2.5 yrs old.

THANKS!

It likely wasn't the Tazer that caused any issues. Your original bad aux battery likely killed the main battery. When one goes it takes the other with it, as they are connected together. Perform the aux delete and change the main. Consider going for a better H7 main.

 

[jludave]

For a while, my Taser had an issue where it would not let certain electronic devices enter sleep mode. Once a month, I would come out to a dead Jeep that a jump could get running again. I eventually had to pull out the Taser to stop the drain as my luck had the dead battery on a work morning, every time.

This was likely due to the Tazer not being setup properly. If you marry the Tazer and make any changes, you need to perform 2 full sleep cycles afterwards. If you don't do this step properly, you can run into issues as you've described above. There is no requirement to update the Tazer when new firmware is released. It will run as is, if installed/setup properly.

 

[Jamrock]

This is a known issue with the JL's.

It is a good idea to replace both batteries at the same time. When you replace one, the older one will drain the power of the newer one.

Most of the posts I have seen suggest that the aux battery will drain the main battery when it goes bad. You have seen it the other way around.

Either way, try replacing both batteries at once. Let us know what happens

 

[Omen]

This was likely due to the Tazer not being setup properly. If you marry the Tazer and make any changes, you need to perform 2 full sleep cycles afterwards. If you don't do this step properly, you can run into issues as you've described above. There is no requirement to update the Tazer when new firmware is released. It will run as is, if installed/setup properly.

Thanks, but my experiences were different. It seem to be ok now after I fed it a few updates.

Mike

 

[Billyg73]

Where can I find the update info for that? Is it pretty easy?

For a while, my Taser had an issue where it would not let certain electronic devices enter sleep mode. Once a month, I would come out to a dead Jeep that a jump could get running again. I eventually had to pull out the Taser to stop the drain as my luck had the dead battery on a work morning, every time.
I have been updating and watching the release notes for the Taser, and I finally felt comfortable re-installing it. So far, so good...

Moral of my story... make sure your Taser is up to date.

Maybe this helps?

Mike

 

[Billyg73]

Any advice on the best aux delete? seems there are a couple ways. pull fuze - isolate the ground. and all that.

It likely wasn't the Tazer that caused any issues. Your original bad aux battery likely killed the main battery. When one goes it takes the other with it, as they are connected together. Perform the aux delete and change the main. Consider going for a better H7 main.

 

[Omen]

Where can I find the update info for that? Is it pretty easy?

Here you go!
https://www.zautomotive.com/tazer-jl-updates/

You need to download an app that then can communicate with the Taser. You have to un-marry/remove the taser and take it to a PC or Mac.

Mike

 

[jludave]

Any advice on the best aux delete? seems there are a couple ways. pull fuze - isolate the ground. and all that.

Pull fuse F42. Disconnect aux battery negative cable and isolate. That's it. You will want to turn off ESS after that. Since you have a Tazer, you can use it to remember the ESS off state so you don't have to push the button every time you start the vehicle.

View this thread:

https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

 

[Stuckinthesand]

As others have said always replace both at the same time. The best bypass is as @jludave mentioned above. I have been running this way for 2 years now with an H7 battery with no issues. I even pulled the aux battery out and taped off the cables in the box.

 

[Reinen]

The worst thing you can do for battery longevity is pair a new battery with an older battery. Main & Aux work as a pair and the older battery will suck the life out of the new battery 24/7 and kill it very quickly.

Always replace Main & Aux at the same time regardless of how they test. Consider them two parts of the same battery because 99.99% of the time, they are. Anyone who says it's okay to only replace one battery is either clueless or sells batteries.

Be aware that the only thing the Aux battery delete accomplishes is to reduce your cold start CCAs by 20-30% and give you little to no warning when your Main is about to fail. It's just a kick the can down the road solution and in the long run you end up being much more likely to discover you have a battery failure by getting stranded with a suddenly DOA Jeep.

 

[Fitzz47]

Your batteries are under warranty for the first 3 years or 36,000 miles. Let your dealer replace them for free. I have a 2018. Batteries were replaced three years ago under warranty. They just started acting up today. So I pulled f42 and the aux. neg. Cable. Started right up.

 

[Mguy]

Be aware that the only thing the Aux battery delete accomplishes is to reduce your cold start CCAs by 20-30% and give you little to no warning when your Main is about to fail. It's just a kick the can down the road solution and in the long run you end up being much more likely to discover you have a battery failure by getting stranded with a suddenly DOA Jeep.

Sorry, not much of this is accurate. To be clear:

1) "Aux battery delete," which includes the PCR fuse pull, electrically isolates the aux battery but does NOT effect ESS at all.

2) The main battery alone, if an H7 and if free from the inherently lousy dual battery system, will be large enough and totally reliable to start 99% of JLs located on dry land between the poles and the equator, so long as their owner's driving/maintenance habits are average for where the JL is used.

3) The battery warning attributes of ESS function fully and perfectly for single battery owners who use the dash off button intelligently (and don't use hardware/software to disable ESS altogether).

4) A single H7 battery, used by an owner possessing AGM intelligent driving/maintenance habits (meaning, consistency with good AGM charging techniques), will almost certainly provide more than 3 years of reliable starting, regardless of the battery brand.

 

[Reinen]

1) "Aux battery delete," which includes the PCR fuse pull, electrically isolates the aux battery but does NOT effect ESS at all.

I never even mentioned ESS. You're regurgitating rebuttals to points not even made.
Pulling the PCR fuse disables a battery test designed to ensure successful operation. It doesn't isolate anything. It just doesn't test Aux anymore because it will fail.

2) The main battery alone, if an H7 and if free from the inherently lousy dual battery system, will be large enough and totally reliable to start 99% of JLs located on dry land between the poles and the equator, so long as their owner's driving/maintenance habits are average for where the JL is used.

A new battery will but not an older battery. All the problems with this configuration lie towards the end of battery lifecycle. There just isn't a lot of foresight involved with it. It will work just fine until it doesn't work anymore.

3) The battery warning attributes of ESS function fully and perfectly for single battery owners who use the dash off button intelligently (and don't use hardware/software to disable ESS altogether).

It introduces the possibility of browning out and glitching electronics communication during warm starts as it is now impacted by the starter motor draw, aux switches and user modifications connected directly to the Main battery. It also impacts cold starts as there is now 20-30% less power available. A JL with unstable electronics & communications power is a DOA JL. It will fail sooner and makes it more likely to fail at the worst possible time, in the middle of traffic at an intersection.

4) A single H7 battery, used by an owner possessing AGM intelligent driving/maintenance habits (meaning, consistency with good AGM charging techniques), will almost certainly provide more than 3 years of reliable starting, regardless of the battery brand.

So will a properly installed and maintained Main/Aux pair. This is not a benefit in any way.

Sponsored