ESS "Not Ready Battery Charging" question.

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BrntWS6

BrntWS6

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That sounds very suspicious to me. Mine sat on the lot for maybe 8 months before I bought it. It’s my weekend driver and sits often for a few weeks between drives. In almost 8 months I have maybe 4,200 miles on it and I never get that ESS charging error.

I would think that you have if not a problem with one or both batteries then you have a charging system problem. I don’t think the system is bad at charging the batteries if it’s working properly.

User @Jebiruph is the resident expert here on the ESS system it seems, maybe solicit his opinion.

He has chimed in on this thread several times. Its not an error I am getting the system is just charging the batteries. If I drive enough the start/stop engages. I have chalked it up to sitting for extended periods and when I do drive it's often for only 15min.

Not sure what else the dealer can do besides load test the batteries and scan for codes. But using a trickle charger has solved my issue completely.
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dccurtis

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I haven’t followed this thread too closely but did post my experience and wanted to give a follow up.

I was experiencing long charging periods for the aux battery. Finally in mid December it would never charge. I had the jeep in for a safety recall today and had them test the batteries. Sure enough the aux battery failed the test and it was replaced. Working great now. The whole time I never had any trouble with the jeep other then ESS not working (It’s a feature not a bug right!) :)
 

Htfan

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I'm now in "round two" of this ESS battery not ready - charging issue. I had it in the dealership a few weeks ago and they only replaced the smaller (200 CCA) AUX battery. I requested the dealership also replace the main (650 CCA) battery at the same time but they assured me it was good and left the original installed.

Well, ESS worked fine for a couple days and then I started getting the dreaded battery not ready message. I even purchased a battery maintainer to resolve the problem, but still getting ESS battery not ready - charging message. In addition, the EVIC constantly displays 14.2v to 14.7v when the engine is running.

To try and get additional information, I isolated the two batteries after a full maintainer charge to measure them independently. After resting about 4 hours unconnected, here's what I found:

Aux battery dropped from 13.4v to 13.21v (new battery seems strong)
Main battery dropped from 13.4v to 12.58v (original battery seems mediocre)

Could this be my problem? Since the batteries are mismatched, could they be causing the constant charging and ESS not ready?
 

DanFelix

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I had to replace both batteries with better batteries. Both batteries' meter readings were good so I suspect the batteries could not hold a charge. Solved the issue and works fine now.
 

twisty

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My batteries had to be replaced too. Glad it was under warrenty, cant wait to replace both in the future on my own dime. lol

Are Li batteries an option?
 

dccurtis

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I'm not sure what's going on with mine. It worked fine for a day after the secondary battery replacement. But it's been in the charging state ever since. Unfortunately the jeep hasn't been driven very consistently over the last few weeks so maybe it just needs to be driven more so it can charge? I have a feeling that something is wrong though.
 

DanFelix

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I'm not sure what's going on with mine. It worked fine for a day after the secondary battery replacement. But it's been in the charging state ever since. Unfortunately the jeep hasn't been driven very consistently over the last few weeks so maybe it just needs to be driven more so it can charge? I have a feeling that something is wrong though.
That was my same experience. The solution was that both batteries had to be replaced. I first replaced the Aux battery then, two days later replaced the Main battery. The system has worked without fail since. Hope that helps.
 

D60

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My batteries had to be replaced too. Glad it was under warrenty, cant wait to replace both in the future on my own dime. lol

Are Li batteries an option?
I imagine so if you like spectacular fires ;)
 

dccurtis

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That was my same experience. The solution was that both batteries had to be replaced. I first replaced the Aux battery then, two days later replaced the Main battery. The system has worked without fail since. Hope that helps.
Thanks! That is helpful. I’ll report back if it helps anyone else once I get the jeep in to be retested.
 

twisty

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Havent checked into Li batteries for vehicles, only that they are light and the reason I use them on my dirt bike. They work amazing there and last a LONG time.
 

mmcbeat

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I was getting the start stop battery charging messages I took my Wrangler in for service yesterday. I don’t drive my Jeep daily and have driven less than normal the year. According to the tech both batteries checked out OK. The message seems to be generated by the intelligent battery sensor state of charge. Dealer charged both batteries and I ordered a battery tender for future use. I need to drive the Jeep to reset the message.
F8F686CC-B7EC-45EE-A96A-80160514EDDC.jpeg

Do you guys think I’m good to go?
Comments? Thanks.
 

entropy

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I was getting the start stop battery charging messages I took my Wrangler in for service yesterday. I don’t drive my Jeep daily and have driven less than normal the year. According to the tech both batteries checked out OK. The message seems to be generated by the intelligent battery sensor state of charge. Dealer charged both batteries and I ordered a battery tender for future use. I need to drive the Jeep to reset the message.
F8F686CC-B7EC-45EE-A96A-80160514EDDC.jpeg

Do you guys think I’m good to go?
Comments? Thanks.
It is possible. Just so you know I had a similar issue. System will always be charging, work after long drives, then itll break again. Twice I took it to the dealer and they said "it is fine". Well it eventually crapped out. I had to jump the car and I got the "service ESS light". Took the Jeep to the dealer and aux battery was dead, needed to be replaced and apparently something was draining it and it wouldnt charge properly. I asked the. to replace both batteries, but FCA told them to just replace the aux battery. So I know this is gonna fail again.

I dont know what to say. They might be telling you the truth, but you cant trust then. FCA dealers lie. They lie a lot.
 
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