Start/Stop Not Ready - Battery Charging?

mppsu2003

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A couple of days ago I got this message on my 2020 JL...15.7k miles.

Initially it flashed a ' service start/stop' message which went away quickly. Since then its read that message. When driving the dash indicates the battery is between 13.8-14.1 volts.

I read it could be the auxiliary battery causing the issue. I can't imagine the battery is dying already. Its only a year and a quarter old and is used normally (IE hasn't set long periods of time but also not driving hundreds of miles a day)

Any easy troubleshooting tips?
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MauiSteve

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I'm not sure why that would be unless the battery is low. I just received my 21 JL Rubicon this week and right away I got a start/stop not ready message when I pressed the button to turn it off. I'm not sure I'll do anything about it since I don't really care if it is enabled.
 
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WranglerMan

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i just came from the service center today to get some coolant and power steering fluid and was chatting with a Service Advisor that I normally used to talk to when I was getting my Jeep Wave oil changes and I was showing him my new dual battery setup and he advised that the batteries in these JL’s are not lasting long at all as there Service Center is replacing them all the time and it’s both batteries that seem to be dying, contrary to popular belief your EVIC voltage display should not say 14.0+ on the voltage all the time unless your JL stays parked ALOT ....and even then after driving for around 30 mins it should drop into the mid to low 13’s on the display and if it does not and you get those start/stop not ready messages all the time you should have your batteries load tested.
 

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OP... you're probably going to have to get your batteries replaced. Covered under warranty. Happened with mine about a year ago.
 

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i just came from the service center today to get some coolant and power steering fluid and was chatting with a Service Advisor that I normally used to talk to when I was getting my Jeep Wave oil changes and I was showing him my new dual battery setup and he advised that the batteries in these JL’s are not lasting long at all as there Service Center is replacing them all the time and it’s both batteries that seem to be dying, contrary to popular belief your EVIC voltage display should not say 14.0+ on the voltage all the time unless your JL stays parked ALOT ....and even then after driving for around 30 mins it should drop into the mid to low 13’s on the display and if it does not and you get those start/stop not ready messages all the time you should have your batteries load tested.
I would take that advice with a HUGE grain of salt. Remember, these are the same techs who are putting 6qts of oil in.

I got one of the first 2dr JLs that were made in 2018. The EVIC has always shown 14, even on day one of ownership.

I’ve been lucky and have never had any issue with either battery, and never have gotten any ESS error messages. (I do put the batteries on a tender twice a month, and always have.)

All of that said, yes, having two batteries that are different capacities is idiotic. It’s only a matter of time before one of my batteries goes south and takes the other one with it.

@mppsu2003 I’d go to the dealer and have them load test each battery in isolation. They’re under warranty. I would not give a second thought to the 14v on the EVIC. I *would* pick up a Deltran Battery Tender Plus and make a habit of maintaining your batteries to stave off their inevitable demise.

When my ESS battery dies, someday, I will just bypass it and run with one battery. (I don’t use or like ESS.) Genesis system is great if you need it; I don’t.
 

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Because I don't know, how do you put a tender on the smaller battery under the big one?
 

MauiSteve

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If you don’t change anything, the battery tender will maintain both batteries, if they are both good, because they are connected in parallel.
 
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mppsu2003

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I would take that advice with a HUGE grain of salt. Remember, these are the same techs who are putting 6qts of oil in.

I got one of the first 2dr JLs that were made in 2018. The EVIC has always shown 14, even on day one of ownership.

I’ve been lucky and have never had any issue with either battery, and never have gotten any ESS error messages. (I do put the batteries on a tender twice a month, and always have.)

All of that said, yes, having two batteries that are different capacities is idiotic. It’s only a matter of time before one of my batteries goes south and takes the other one with it.

@mppsu2003 I’d go to the dealer and have them load test each battery in isolation. They’re under warranty. I would not give a second thought to the 14v on the EVIC. I *would* pick up a Deltran Battery Tender Plus and make a habit of maintaining your batteries to stave off their inevitable demise.

When my ESS battery dies, someday, I will just bypass it and run with one battery. (I don’t use or like ESS.) Genesis system is great if you need it; I don’t.
Thanks all. Called the dealer today and can’t get an appt until next Saturday (10 days). Is it reasonable to think the jeep should be fine to drive until then without issue (normal driving no long trips or anything)
 

WranglerMan

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@OldGuyNewJeep my main battery died 7 months into ownership, so in Sept of 2018 it got replaced then I had several issues where it had to be jump started and and even after the main got replaced the EVIC usually displayed 14+ volts after being parked for a day and it ALWAYS took a super long drive to get it under 14 volts and even say after a 200-300 mile trip it never got below 13.6 volts and I to used a small 1.25 amp tender all the time.

Im not an Engineer and have no scientific proof but I think the dissimilar batteries along with just the general design is poorly designed and that’s what is causing problems, the fact is the JL uses a Smart alternator and is supposed to charge the batteries as needed and the design from my layman understanding is that it ramps up the charge during the no load periods of driving like deceleration and or braking and mine did that when it was new but that was short lived and then it did it again after I had the battery replaced but that to was short lived but the IBS monitors the main battery and is supposed to keep it fully charged and if it’s always throwing 14+ volts to it then either the battery cannot fully charge or the IBS has an issue or possibly the ESS battery is pulling down the main at a small parasitic rate but all of this is a guess.

I for one got tired of worrying about the dissimilar batteries along with the location and went a different route since I am past the 36k mile warranty and so far my charging system is working outstandingly well and I only see 14+ volts for maybe the first 15-20 mins of driving and within an hour or so of highway driving I normally see 12.9-13.3 on the EVIC.

Also if you want to bypass the small ESS battery once it dies and run with one battery I would personally remove the ESS battery and run its positive up to the main crank and then disconnect the ESS negative tied to the main crank this way it assures you that the ESS battery won’t possibly pull power from the main, this is effectively what I did but went to a dual battery system with two full size batteries that are tied together 99.9% of the time as one battery
 
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If you don’t change anything, the battery tender will maintain both batteries, if they are both good, because they are connected in parallel.
Hey Stephen:

I don't want to be a pedantic jerk but rather make a relevant point. Yes, when parked, your 3.6L JL's batteries are connected in parallel Stephen, no doubt.

Accordingly, putting a charger's leads on the positive side of either battery and the negative side of either battery will charge both batteries. Of course with the ESS battery hidden in the 3.6L JL the easiest play is to put a charger's leads on the main battery's positive and negative terminals.

Only ESS events and a test of the ESS/Aux battery prior to engine crank isolate those batteries. A dead ESS/Aux battery, incapable of accepting a charge, will strand a 2018 3.6L JL that hasn't gotten a flash of the PCM update is TSB 18-092-19.

With it, or in 2019 model year or later 3.6L JLs the vehicle, subsequent crank attempts after the first failed one will switch over to the main battery to attempt the crank, and if successful disable ESS and indicate so on the dash, only clearing this error after an energized ESS/Aux battery is found upon subsequent cold cranks.

The logic of disabling ESS when running only one battery is sound here, despite a fair number of vehicles doing ESS systems with one battery. This is because an ESS event could rob the main battery of cranking power in the Wrangler design, which may push things to a greater limit than other vehicle's 1 battery ESS systems, given the Wrangler's primary use of the ESS/Aux battery during ESS events, preserving the main battery for the crank thereafter.
 

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A couple of days ago I got this message on my 2020 JL...15.7k miles.

Initially it flashed a ' service start/stop' message which went away quickly. Since then its read that message. When driving the dash indicates the battery is between 13.8-14.1 volts.

I read it could be the auxiliary battery causing the issue. I can't imagine the battery is dying already. Its only a year and a quarter old and is used normally (IE hasn't set long periods of time but also not driving hundreds of miles a day)

Any easy troubleshooting tips?
Hi @mppsu2003:

You may appreciate this, but that reading on the dash is really the alternator making up for lack of voltage it sees in the batteries once the engine has cranked.

If you press the start button twice without your foot on the brake of a parked 3.6L JL, and switch the screen to its voltage readings you will get a real reading of the composite voltage of both batteries.

Don't forget once done to press the start button one more time to turn the vehicle off.
 

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Another thought @mppsu2003 ...

I realize my prior post my only end up leading to the question of how one tests the voltages of each battery separately.

To test either battery's voltage alone, the procedure inside the vehicle is the same. It's what you do temporarily under the hood first that matters.

To get the ESS/Aux batter's voltage temporarily, disconnect all cables from the main battery's negative post first. Have them dangle in the air. Then run your in vehicle voltage test. Don't forget to put things back.

To get the main battery's voltage, visualize the two cables connected to the main batteries negative post. Temporarily disconnect the one closest to the passenger's side. Have it dangle in the air. That's the cable whose other end leads from the ESS/Aux battery's negative post. The reading in your vehicle will be main battery voltage only. Don't forget to put things back.
 

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Thanks all. Called the dealer today and can’t get an appt until next Saturday (10 days). Is it reasonable to think the jeep should be fine to drive until then without issue (normal driving no long trips or anything)
Yep I'd definitely let the dealer figure it out. My 2018 sits often. It just passed 28k miles. I've started to put it on a battery maintainer when it sits for 4-8 weeks and have the original batteries. Just hook the maintainer to the posts on the main battery.
 

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Thanks all. Called the dealer today and can’t get an appt until next Saturday (10 days). Is it reasonable to think the jeep should be fine to drive until then without issue (normal driving no long trips or anything)
I believe it is safe. More importantly, let me tell you why at the risk of rehashing some of the above.

If you have a battery problem I'd bet it more likely to be the ESS/Aux battery.

If this battery lacks adequate power, if you are operating a 3.6L JL on or after 2019 (and at least with respect to the model year you are) you vehicle will not crank, but

upon second attempt it will switch over to the main battery and attempt the crank. If successful the vehicle will disable ESS, and tell you so in the diagnostic panel--a good thing as you shouldn't be running ESS with one working battery (any Genesis brand configurations not considered here). For there on it, you will only run with main battery until the ESS/Aux is replaced.

At the first cold crank attempt that the ESS/Aux battery is found to have power, the diagnostic code will self clear and you'll be running on two batteries again.

My answer would be tons different for a 2018 3.6L JL without flash PCM update is TSB 18-092-19. In this case a dead ESS/Aux battery will strand the vehicle.

There are tons more on this topic but..not here.

: - )
 

MauiSteve

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Lots to absorb about ESS. Seems like an overly complex system.
 
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