Problem with 2018 JL ESS battery is real

Vahdettin

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Until I took my JLU in today, the auto start-stop has only kicked in once since September of last year. The EVIC showed “not ready. battery charging” all that time. Today the secondary battery was replaced under warranty, the software upgraded and everything is back to normal. Apparently the charging regulator software was not conditioning the battery correctly leading to a slow loss of capacity.

This is just a FYI as I know others have had a difficult time getting their dealers to admit that this is a widespread problem. My dealer here in WA had two other JLs in for the same issue at the same time as me so it is not uncommon.
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Sierra Nevada

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Had both batteries replaced in late 2019 because I couldn't start 2018 JLUR. I did recall ESS was not working for probably a year prior to battery replacement. After battery replacement, ESS worked again.

Just noticed this week ESS is not working again ... and has not for months. So, whatever they did to fix this problem did not work. I'm going to bring in the Jeep soon. I've got a life time warranty.
 

#diesel

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Start/stop not working for at least 3 months. Recently noticed display says battery charging for weeks.
It’s at the dealer now.
I’ve heard a bad ESS battery has stranded folks.
Anyone know if rolling off my six speed would work?

F91BA73E-B423-498C-87B2-BD1BAB087B2A.jpeg
 
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Vahdettin

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sourdough

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Can you elaborate on "update the software". TSB ?
 

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Much has been written on the forum about the ESS battery, the difficulty for ESS to engage, and the ability for it to strand JL's, particular 2018 3.6L engine ones.

TSB 18-092-19 will get a 2018 3.6L to behave like the 3.6L in model years 2019 and beyond such that a dead ESS battery will not prevent the vehicle from cranking.

JL's, particularly 3.6L ones test the ESS battery prior to attempting a cold crank. In factory 2018's if this battery lacks adequate charge the crank won't be attempted: even if your main battery is fully charged. In 2019's and beyond, or 2018's with this TSB, the vehicle switches to the main battery and, upon the user's second crank attempt and beyond, it attempts start the engine from the main battery.

Both batteries are in parallel 99.9% of the time. It's only this instant during pre-crank, and ESS events when the batteries are isolated. Accordingly, placing a trickle charger on the main battery's terminals while it's parked, if access to shore power is available, will charge both batteries and likely get ESS to return.

It's not an ideal solution: this trickle charging, but it does work.
 

#diesel

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The dealer replaced both batteries and ESS is ready. I guess about 30 months on original batteries is the norm?
 

SouthCo

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Much has been written on the forum about the ESS battery, the difficulty for ESS to engage, and the ability for it to strand JL's, particular 2018 3.6L engine ones.

TSB 18-092-19 will get a 2018 3.6L to behave like the 3.6L in model years 2019 and beyond such that a dead ESS battery will not prevent the vehicle from cranking.

JL's, particularly 3.6L ones test the ESS battery prior to attempting a cold crank. In factory 2018's if this battery lacks adequate charge the crank won't be attempted: even if your main battery is fully charged. In 2019's and beyond, or 2018's with this TSB, the vehicle switches to the main battery and, upon the user's second crank attempt and beyond, it attempts start the engine from the main battery.

Both batteries are in parallel 99.9% of the time. It's only this instant during pre-crank, and ESS events when the batteries are isolated. Accordingly, placing a trickle charger on the main battery's terminals while it's parked, if access to shore power is available, will charge both batteries and likely get ESS to return.

It's not an ideal solution: this trickle charging, but it does work.
I have a feeling this is the TSB the OP is talking about. I read a lot and have not heard of a TSB that updates software to regulate how the batteries are charged. Either OP is mistaken or dealer is lying.

OP, post a pic of your paperwork showing the TSB please.
 
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Vahdettin

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Can you elaborate on "update the software". TSB ?
Good question and I was wondering too. I can’t imagine it was a Uconnect update as I self replaced my 5” for a 7” and I heard the dealers won’t go near it if that’s the case. Maybe there’s engine specific software?? I don’t know much about it but I’ll find out what they did tomorrow and post back.
 

SouthCo

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The dealer replaced both batteries and ESS is ready. I guess about 30 months on original batteries is the norm?
My 2018 has both original batteries and the start stop kicks in often if I don't hit the button to override it. And mine is just about at 30k miles so it sits often. I do put in on a trickle charge a few times a year.
 
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Vahdettin

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The dealer replaced both batteries and ESS is ready. I guess about 30 months on original batteries is the norm?
That time-frame is exactly what I experienced. And it doesn’t appear to be related to miles travelled as I’ve had mine for 3 years but haven’t even reached 14k yet.
 

Gee-pah

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I have a feeling this is the TSB the OP is talking about. I read a lot and have not heard of a TSB that updates software to regulate how the batteries are charged. Either OP is mistaken or dealer is lying.

OP, post a pic of your paperwork showing the TSB please.
I know of no TSB either that changes how the batteries are charged. At all times that the ICE is running (or the vehicle is parked) in the 3.6L the two batteries are in parallel.

When the engine is on the alternator charges both batteries. At rest, a trickle charger connected to the positive of either battery and the negative of either battery charges both batteries: such being nature of parallel connections.
 

Gee-pah

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Covered many times elsewhere on the forum, hooking up dissimilar sized batteries like the 3.6L does is, to the battery purist (and even the mere battery enthusiast) simply not a good idea---and yet this is how Stellantis designed the system.

Without being at the meetings, I think somebody suggested that ESS run on one battery like many other vehicles, and engineers said that such an idea would be bad given all the electric drawing accessories (i.e. appliances) Wrangler owners run.

I'll bet that the engineers then proceeded to explain how two equally sized batteries would be the best option, but the bean counters found savings in one big and one little battery, and the suits went for it.
 
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Vahdettin

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When the engine is on the alternator charges both batteries. At rest, a trickle charger connected to the positive of either battery and the negative of either battery charges both batteries: such being nature of parallel connections.
Just to clarify, you're not talking about an actual trickle charger, right? Do you mean that naturally one battery will charge the other other based on the difference in potential?

And I just looked over my paperwork and there is no mention of a TSB or any kind of software update. I should have known. Grrrr.

Regardless, if the problem was a bad battery and replacing it with a working one from a (hopefully) better batch fixes the issue, I'm happy. I see all the other threads where people were stranded due to both batteries going out so I'm glad I was able to catch it when I did.

Thanks for all the input!
 
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