Push to start not working first try. Second try works fine.

[garykk]

Happened to me. One year old , original battery , 2024 2-door Rubicon. Drove to the beach, didn't use it for 6 days. When I went to start it this morning exactly what you described happened. Has happened to me once before when it was in the garage for a few days without using it. It's a bit disconcerting on a one year old battery. Both times it did start after several attempts. Thinking maybe I should have the battery tested..

My aux. battery didn’t even make it a year.

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[zouch]

mine made it close to 2, but that was it.

My aux. battery didn’t even make it a year.

 

[Pig-Pen]

still on original 2018 batteries? wow. i thought mine was impressive. i replaced mine some time last year. got an agm from walmart, which has the best warranty i could find. i went with the upgraded size battery. i also did the aux delete as well. been working great ever since. dont waste money on a new aux battery. just disconnect it and forget about that useless boat anchor.

 

[Heimkehr]

got an agm from walmart, which has the best warranty i could find. i went with the upgraded size battery.

I intend to replace the OEM H6 with a larger H7, when it becomes necessary to replace the original battery. It seems that all I have to do to accommodate the switch is to remove a small plastic spacer block in the battery tray. Was that your experience, also? TIA.

 

[Pig-Pen]

I intend to replace the OEM H6 with a larger H7, when it becomes necessary to replace the original battery. It seems that all I have to do to accommodate the switch is to remove a small plastic spacer block in the battery tray. Was that your experience, also? TIA.

yessir. super easy.

 

[Kyanche]

My battery tray was full of mouse poop I'm going to get one of those genesis ones. No idea why they thought making the tray have sides like a box/dish was a good idea. Unless I use a shop vac that aint coming out and I'm really sad about using my shop vac to clean up poop.

 

[SaintNick]

I have 38K miles on my batteries. I think I should preemptively change my main battery. Should I just delete my aux battery at same time?? I live in Southern Utah now and am hundreds of miles from anyone on a weekly basis and don't want to get stuck somewhere.

 

[Bbp]

This happens on my 24 with 14k miles, been happening for a couple thousand miles.

 

[Kyanche]

I have 38K miles on my batteries. I think I should preemptively change my main battery. Should I just delete my aux battery at same time?? I live in Southern Utah now and am hundreds of miles from anyone on a weekly basis and don't want to get stuck somewhere.

You can bypass or unhook the aux battery easily enough, so it's up to you. I was tempted to get a dual battery system but they use group 25 batteries, which are actually kinda hard to find. Can't just get a $150 agm at walmart, gotta buy optima or full throttle or odyssey.

The aux battery is so dumb. Aside from the acdelco gold they all have 1 year warranties.

 

[Husky Man]

I have a 2021 JLU with 3.0 EcoDiesel, I didn’t have any warning signs, just Wednesday afternoon went out to start the Jeep, and the battery was too low, to start. WTF, couldn’t find anything left on to cause a draw, didn’t think too much about it.

Thursday(yesterday) afternoon, went out to the Jeep, and Dayum, interior lights come on, maybe a bit dim, but female dog won’t start again. Had to use the Wife’s Expedition to go get the GrandDogter, the Daughter was on her way to the hospital, expecting her first, a Boy.

I have 87,000 miles on it, not quite 4 years old, and have heard of the aux batteries causing issues, called the dealer, and the service writer said, yep that’s about the expected life for those.

Are there any changes in the 21 JLU, or can I just replace the main battery, disconnect the the ground cable that Doesn’t go to body ground, and pull fuse 42?

Are there any disadvantages to doing an Aux Bat delete? ( I consider permanently disabling ESS a Bonus)

anything more that I need to do, or know?

The Wife let me know a couple hours ago, little Everett is Perfect, and Emmy handled it like a Rockstar, so something went Right today

Not sure yet how the GrandDogter is going to accept it though, she’s an almost 7 year old American Bulldog, that is used to being an only child, and can be a pouter, got my fingers crossed there

Doug

 

[AndySpill]

Are there any disadvantages to doing an Aux Bat delete? ( I consider permanently disabling ESS a Bonus)

I run both batteries and ESS events. I point this out to make clear that my answer is about what works for you, not about getting others to adopt my approach unless it works for them.

With this said, and biases disclosed, I am extremely hard pressed to find legitimate reason to retaining the Aux battery in the electrical schematic of the vehicle, as both a power source and point the alternator needs to recharge, provided you have--as you state--committed to not running ESS events.

I had this crazy daydream that I'm on the Family Feud TV Show and the question is "top reasons to keep the JL Aux battery even if you've turned ESS off." What might I say in desperation:

* It can be useful to run appliances off of while camping, isolated from the main battery, and only reconnect it after the engine has been cranked by the main battery.

* It can help crank the engine if it, rather than the main battery, is in a better state of health than the main battery: when usually, if one battery is to die, it's the Aux.

That's about all I've got. Maybe someone else has something.

Of course for those committed to running ESS events I advocate the 2 battery retention in JLs with this setup. Sure, everyone else out there is doing ESS with one battery but I'm just worried about the perfect storm of a cold night, near end of its life main battery, a long traffic light, and too many (aftermarket) appliances running during that ESS event, that manages to cause the main battery's voltage to drop below that needed to crank the engine, as it runs these appliances during an ESS event, before the ESS event early terminates due to this voltage drop.

This may be alarmist, but I just don't want anyone unable to crank at a traffic light.

 

[Husky Man]

Andy, Thank You, that’s why I asked, because there is a lot I don’t know about how modern vehicles operate, and like it or not, that is what I have to live with.

Things are so much more complicated than they need to be, sometimes I think that it’s just so automotive engineers can justify their jobs.

I would be Happier if ESS wasn’t even in my JLU, but I didn’t realize that nonstarting draws, were on the aux bat.

I learned my new thing for the Day

Doug

 

[Heimkehr]

I have a 2021 JLU with 3.0 EcoDiesel

I didn’t have any warning signs, just Wednesday afternoon went out to start the Jeep, and the battery was too low, to start.

That was my precise experience with my 2021 JLU this past Monday.

The original H6 had reliably cranked the engine Sunday evening. On Monday morning, I pressed the Start button, and the gauge needles performed an incomplete diagnostic sweep, after which a couple (not all) of the idiot lights illuminated. Two more starting attempts produced the same outcome.

This not being my first rodeo with automotive batteries, I knew exactly what was occurring.

Lead acid batteries that I've owned in the past would give me warning signs, like slower cranking, to make plain that they were just about at the end of their service life. The factory AGM in the Jeep, which is also lead acid chemistry, just clocked out and that was that. I observed 10.3V on the multimeter prior to taking it in for a core charge refund.

The factory battery had lasted four years, almost to the day. It was replaced with an H7 AGM later in the morning. Done and done.

 

[Husky Man]

I have always had standard lead acid batteries in the past, and was used to them degrading more progressively, so my first thought was that I had left something on.

Did you replace both batteries, or do an Aux Bat Delete?
What are your thoughts/advice?

Doug

 

[58Willys]

Well, I’m with Andy on this one. I have no problem with ESS, and I’m still running it. Definitely saves fuel and engine idle time in urban stop light areas, and I can’t ever remember reading here about anyone having to replace worn out starters. And no it doesn't take more fuel to start it; and there's plenty of oil in the top end for lubrication.

If you’re running ESS, might as well have a dedicated battery to power lights, blower fan, and whatever, while your stopped; and not run your main battery down.

I've had my 2018 for almost six years and I replaced my original batteries, which were dying after two and a half years. I very recently load tested the three year old NAPA replacement batteries, and they are in great shape.

I think the biggest issue with two battery system, is the crap OEM batteries.

I like ESS, I like my aux battery - flame suit fully zipped.

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