Anyone had problems with the stock Jeep auxiliary battery? If so, how did you fix it?

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JoshDante

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I'm seeing a lot of posts on YouTube about an expired aux battery causing the main battery to also fail, soon thereafter. Some even said that they couldn't even jump the main battery with a battery starter pack at that point. Just wondering how common this is before I set out on travels. :)
 
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jeepers29

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I'm seeing a lot of posts on YouTube about an expired aux battery causing the main battery to also fail, soon thereafter. Some even said that they couldn't even jump the main battery with a battery starter pack at that point. Just wondering how common this is before I set out on travels. :)
If your batteries are approacing 3 years, then you should think about changing them. If you go on the jeep forums there are many threads about the the cheap batteries and people being stranded. Lots of people eliminate the aux battery and put in a larger main battery or go to a dual battery setup by Genisis. I have a battery charger/maintainer on both my jeeps to keep them charged when ever they are not being used.
 

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+1 about jeepers29 post.

Predicted battery life span is 3-4 years. Here in CA you can have a six year old battery that still starts the car. According to the owner "the battery is still good". Unfortunately, its not. "If" one battery took out the other battery, they were both bad to start with. Most likely the owner only replaced the one that totally failed.

The biggest issue I have about things people post in forums is, people give opinions which may not have any basis on fact. Its what they "think" is going on or their just parroting bad or partial information they read somewhere else. They also commonly blame what they see which is most likely just a symptom.

Just remember, the warmer your climate, the longer batteries appear to hold on. Back to the original question, "if" someone has a battery issue, is it actually the battery(s) that's the issue? The biggest killer of batteries that are under 4 years old is something pulling power with the key off. Also if a battery goes to zero, it pulls life off fast. The longer it stays at zero the weaker the battery is "If" you can even bring it back.
 
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bgenlvtex

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AGM, They are 3 year batteries.
I got my 2020 in 2019 and sold it a month ago.
I was on my 3rd set of batteries.
 

JoshDante

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If your batteries are approacing 3 years, then you should think about changing them. If you go on the jeep forums there are many threads about the the cheap batteries and people being stranded. Lots of people eliminate the aux battery and put in a larger main battery or go to a dual battery setup by Genisis. I have a battery charger/maintainer on both my jeeps to keep them charged when ever they are not being used.
Good to know - sorry if this is a noob question, but how would I select a larger battery if I delete the aux battery and also, would you need to go larger even if the ESS were disabled or could you get same battery as original, in that case? I ask the second question because I heard that the aux battery only powers ESS. That doesn't sound right, but maybe it's true. There is one scant page on the power inverter setup in the manual, not much to go off of, really.
 

JoshDante

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+1 about jeepers29 post.

Predicted battery life span is 3-4 years. Here in CA you can have a six year old battery that still starts the car. According to the owner "the battery is still good". Unfortunately, its not. "If" one battery took out the other battery, they were both bad to start with. Most likely the owner only replaced the one that totally failed.

The biggest issue I have about things people post in forums is, people give opinions which may not have any basis on fact. Its what they "think" is going on or their just parroting bad or partial information they read somewhere else. They also commonly blame what they see which is most likely just a symptom.

Just remember, the warmer your climate, the longer batteries appear to hold on. Back to the original question, "if" someone has a battery issue, is it actually the battery(s) that's the issue? The biggest killer of batteries that are under 4 years old is something pulling power with the key off. Also if a battery goes to zero, it pulls life off fast. The longer it stays at zero the weaker the batter is "If" you can even bring it back.
Thanks for the info :)
 

jeepers29

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Good to know - sorry if this is a noob question, but how would I select a larger battery if I delete the aux battery and also, would you need to go larger even if the ESS were disabled or could you get same battery as original, in that case? I ask the second question because I heard that the aux battery only powers ESS. That doesn't sound right, but maybe it's true. There is one scant page on the power inverter setup in the manual, not much to go off of, really.
From what I have read on the jeep forums, the main battery tray will fit a 94 battery. The aux only keeps things running when the start/stop is stopped at lights, ect. The bigger battery is used to keep up with the start stop functions on it's own.There is a process that needs to be done. Pulling a fuse, 42, I beleive and securing the ground from the aux battery. You will need to read the thread to make sure I am remembering correctly.
 
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Kent R

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I'm seeing a lot of posts on YouTube about an expired aux battery causing the main battery to also fail, soon thereafter. Some even said that they couldn't even jump the main battery with a battery starter pack at that point. Just wondering how common this is before I set out on travels. :)
Just to be clear, you are talking about a JL or JT with the small auxiliary battery under the main battery.
If this is the case then the best and most definitive fix is to install a duel battery set up, there are lots of kits out there I happened to use the Genesis with Odyssey batteries. Three years and absolutely no issues.
 

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I had my aux replaced under warranty about a year ago, they wouldn't do the main at the same time. I am about to upgrade the main to an H7 and probably bypass the aux (pull fuse 42 and isolate negative from main battery) so I don't have another issue with it in the future. From other jeep forums this appears to have worked for years without issue at this point for others.
 

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I installed the Genesis dual battery system which replaces the both the main and auxiliary batteries with a new tray and dual group 25 main batteries. I also installed a Tazer unit which allowed me among other things to turn off the stop-start system without having to remember to manually do that each time I drove the vehicle.