Your battery voltage - truck off and at rest

BearFootSam

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Which I find interesting as if these were any other batteries or vehicles, I'd be trying to figure out why the batteries never fully charge with the system voltage running over 14 volts while running. Mine runs 14.5 and higher much of the time, that's well into the rage to fully top off an AGM battery.
And while it cranks and works fine even when it's 0 outside, 12.3 is not a fully charged battery.
When searching using Bing or Google and looking for things like "what is the voltage of a fully charged AGM battery" you always get 12.6 or better and even thought SoC charts don't agree on exact numbers, they all agree - 12.4 or less is only partially charged, the best chart saying 75% while the worst saying 60% charged at 12.3 volts.

So, automotive EEs here - what's up with this? I can go to my cars any time and find the batteries even after sitting 2 to 4 weeks have a charge of over 12.5 volts and those start out at 12.6 while a full AGM starts out higher.

In short - why aren't Jeep vehicles fully charging AGM batteries, or, are all of the battery companies - those that MAKE and sell AGM batteries, full of bunk when they say that 12.4 isn't fully charged?
Someone is not telling the truth.

In any case, my ESS only works when the truck is driven for hours, or I charge the batteries overnight, otherwise, the batteries sit at 12.3 volts or LESS and the ESS doesn't work with a battery charging message.

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And this shows the voltage with the battery under a load ->
So one could explain a measure of 12.5 volts at the terminals away if there's a fair draw on the battery at the time. It would still be 100% charged IF there was a load like shown here - but mine measured 12.25 volts (and less) so even assuming there's a discharge on it to keep the truck in listen mode, it's still only 80% charged!

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It's been my experience and the wisdom I've received that most vehicles don't fully top off their batteries. From my reading the best thing you can do for longevity is to plug in a battery tender every now and again.

On my Triumph Tiger my dealer thoughtfully installed an SAE pigtail for easy charging and accessories. I plan to do the same on my JT. Aerostich sells an sae cap/ voltage meter that let's me check SOC with a button.

My bike for instance has a key transponder that is always on and draws some current. The JT's are worse with the remote start and unlock receiver always online. Then you have the UConnect vehicle location and status connection sending 4G data meaning the transceiver and computer need to run periodically. All of these devices together can drain your battery over time.

One thing I dislike about ESS is that if you are only taking shorter trips, the restart consumption may exceed the recharge input during a drive cycle. So over time you can get a net loss of charge, hence a trickle charger being important.

A few weeks after purchasing the JT I put a battery tender on and it took over 12hr to show full charge. Interestingly, after charging I got an ESS error for the first few drive cycles. I subsequently learned that the system looks for a level charge between the main and alt batteries. Because I hooked the charger to the main battery I figure it created a charge disparity that triggered the warning. That it stopped triggering tells me that the ESS battery was able to come up to the main charge state during those drive cycles. Henceforth I plant to attach the charger to main positive and the ground bus to see if it also charges the alt battery.

To sum it up, battery tender, battery tender, battery tender.
20221022_091814.jpg

 

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Seems like we really need a display that will capture the SOC of both main and aux battery. At least be able to toggle back and forth between the two.
 
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ShadowsPapa

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It's been my experience and the wisdom I've received that most vehicles don't fully top off their batteries. From my reading the best thing you can do for longevity is to plug in a battery tender every now and again.

On my Triumph Tiger my dealer thoughtfully installed an SAE pigtail for easy charging and accessories. I plan to do the same on my JT. Aerostich sells an sae cap/ voltage meter that let's me check SOC with a button.

My bike for instance has a key transponder that is always on and draws some current. The JT's are worse with the remote start and unlock receiver always online. Then you have the UConnect vehicle location and status connection sending 4G data meaning the transceiver and computer need to run periodically. All of these devices together can drain your battery over time.

One thing I dislike about ESS is that if you are only taking shorter trips, the restart consumption may exceed the recharge input during a drive cycle. So over time you can get a net loss of charge, hence a trickle charger being important.

A few weeks after purchasing the JT I put a battery tender on and it took over 12hr to show full charge. Interestingly, after charging I got an ESS error for the first few drive cycles. I subsequently learned that the system looks for a level charge between the main and alt batteries. Because I hooked the charger to the main battery I figure it created a charge disparity that triggered the warning. That it stopped triggering tells me that the ESS battery was able to come up to the main charge state during those drive cycles. Henceforth I plant to attach the charger to main positive and the ground bus to see if it also charges the alt battery.

To sum it up, battery tender, battery tender, battery tender.
20221022_091814.jpg
There is something to some of that, especially for some people who do mostly shorter drives.
Supposedly AGM batteries "charge faster" than others but I find that not fully true when charged in a vehicle because the PCM modulates the voltage based on other factors.

On the other hand, last week I drive my truck 20 miles and for 10 of that it was running 14.7, and most of the rest when I hit I80 was at 14.8 volts. Plenty of voltage and this truck seems to be doing a lot better than my 2020 - so far.
My 2020 did better after I fully charged both batteries apart from each other, twice, and reset the IBS. Still, it seldom read 12.7-12.8, which is a fully charged AGM, after normal driving.
 

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The Stop/Start on my 2020 is not working at times. When it is not working, it shows "Stop/Start not working-battery charging". When it is not working, the voltmeter in my truck shows high (more than 14.1v). This means that the system in my truck has recognized the battery condition and responded with increased voltage. A one hour drive is NOT enough to enable the Stop/Start. All of this points to the aux battery needing replacement (32 months, 34,000 miles). I have a dealer appointment Monday morning. I'll let you know how it goes.
 

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The Stop/Start on my 2020 is not working at times. When it is not working, it shows "Stop/Start not working-battery charging". When it is not working, the voltmeter in my truck shows high (more than 14.1v). This means that the system in my truck has recognized the battery condition and responded with increased voltage. A one hour drive is NOT enough to enable the Stop/Start. All of this points to the aux battery needing replacement (32 months, 34,000 miles). I have a dealer appointment Monday morning. I'll let you know how it goes.
That's exactly what was happening with mine for a couple months before my truck wouldn't crank without a jump. Took it in and both batteries were trashed. If you're starting to see this, you probably want to replace that aux before you lose your main too.
 


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ShadowsPapa

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When it is not working, the voltmeter in my truck shows high (more than 14.1v). This means that the system in my truck has recognized the battery condition and responded with increased voltage.
That's not very high - and likely wouldn't fully charge a battery that's down by much. These will crank up 14.7 even 14.8 volts when the batteries are low or there's a demand on the electric system or - it's cold outside as batteries take more voltage to charge when cold than when warm. So if it was cold, 14.1 isn't going to charge AGM batteries well.
In fact, old-school wet lead acid batteries charged at 13.8-14.2 volts so 14.1 isn't high by any means.
Frankly, as AGM batteries approach 3 years, my experience and what battery vendors have even said, they are getting long in tooth.

Have the batteries been fully charged using an AGM charger, and the IBS reset?
 

Andy29847

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That's not very high - and likely wouldn't fully charge a battery that's down by much. These will crank up 14.7 even 14.8 volts when the batteries are low or there's a demand on the electric system or - it's cold outside as batteries take more voltage to charge when cold than when warm. So if it was cold, 14.1 isn't going to charge AGM batteries well.
In fact, old-school wet lead acid batteries charged at 13.8-14.2 volts so 14.1 isn't high by any means.
Frankly, as AGM batteries approach 3 years, my experience and what battery vendors have even said, they are getting long in tooth.

Have the batteries been fully charged using an AGM charger, and the IBS reset?
This is really simple for me. I go out in the morning and start my truck. The message center, on screen 6, gives the message, "start/stop not working-batteries charging. I switch to the volt meter and the voltage is more than 14.1. If I drive for an extended period of time, the charging voltage drops in to the 13.7-13.8 range and the stop/start will work, i.e., it takes a long time for the battery to charge. When I go out the next morning, I get the trouble message again. a 10 minute run to McDonald's is not enough to charge the battery.

No, I have not used a home charger to charge the batteries. If I have to do that, I may as well have an electric car. :)

AGM batteries do charge at a higher rate, but float voltage is well below 14v. Obviously, if the vehicle voltmeter is showing charge numbers in excess of 14v, then the battery is losing its charge between drives. Also, it should not take hours a good battery to charge to an acceptable level.
 

Andy29847

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That's exactly what was happening with mine for a couple months before my truck wouldn't crank without a jump. Took it in and both batteries were trashed. If you're starting to see this, you probably want to replace that aux before you lose your main too.

I am going to insist they replace both batteries. Wish me luck.
 

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I am going to insist they replace both batteries. Wish me luck.
Good luck. You can insist all you want. FCA has a specific outlined procedure for battery replacement under warranty. If the dealer doesn't follow procedure, they don't get paid. If the battery testing doesn't meet the specified criteria, it doesn't get replaced.
 

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Good luck. You can insist all you want. FCA has a specific outlined procedure for battery replacement under warranty. If the dealer doesn't follow procedure, they don't get paid. If the battery testing doesn't meet the specified criteria, it doesn't get replaced.
I'm looking for the criteria. I haven't found it yet, but I found this:

MOPAR® AND MAGNETI MARELLI OFFERED BY MOPAR REPLACEMENT BATTERY LIMITED WARRANTY Batteries found to be defective in materials or workmanship will be replaced at no charge for the part-specified free replacement period from the date of purchase, as noted below. Batteries installed on an FCA US LLC vehicle covered by the New Vehicle Basic Limited Warranty, which are found to be defective, are warranted for the remainder of the New Vehicle Basic Limited Warranty, or within the free replacement period, whichever is more favorable to the customer. If the vehicle is equipped with a prorated warranty battery (not all batteries include a prorated warranty, see the top of the battery for warranty details), the owner may receive a prorated allowance toward the purchase of a new Mopar® or Magneti Marelli Offered by Mopar replacement battery. If the vehicle is not equipped with a prorated warranty battery, is no longer covered by the New Vehicle Basic Limited Warranty, and the free replacement period for the Mopar and Magneti Marelli Offered by Mopar Battery Warranty has expired, the owner may receive a prorated allowance toward the purchase of a new Mopar or Magneti Marelli Offered by Mopar replacement battery. This warranty is given only to the original retail purchaser, and this warranty is thus nontransferable. The prorated amount will be computed by dividing the number of months since the date the battery was purchased or installed as original equipment (as shown by the date on the customer repair order or parts counter ticket) by the number of months of proration shown on the battery and multiplied by the purchase price of the battery. A battery that fails under the New Vehicle Basic Limited Warranty will be replaced with a Mopar battery of equal or next highest amp-hour rating. WHAT IS NOT COVERED: Batteries that are discharged are not considered defective.

It is confusing. :)
 


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I'm looking for the criteria. I haven't found it yet, but I found this:

MOPAR® AND MAGNETI MARELLI OFFERED BY MOPAR REPLACEMENT BATTERY LIMITED WARRANTY Batteries found to be defective in materials or workmanship will be replaced at no charge for the part-specified free replacement period from the date of purchase, as noted below. Batteries installed on an FCA US LLC vehicle covered by the New Vehicle Basic Limited Warranty, which are found to be defective, are warranted for the remainder of the New Vehicle Basic Limited Warranty, or within the free replacement period, whichever is more favorable to the customer. If the vehicle is equipped with a prorated warranty battery (not all batteries include a prorated warranty, see the top of the battery for warranty details), the owner may receive a prorated allowance toward the purchase of a new Mopar® or Magneti Marelli Offered by Mopar replacement battery. If the vehicle is not equipped with a prorated warranty battery, is no longer covered by the New Vehicle Basic Limited Warranty, and the free replacement period for the Mopar and Magneti Marelli Offered by Mopar Battery Warranty has expired, the owner may receive a prorated allowance toward the purchase of a new Mopar or Magneti Marelli Offered by Mopar replacement battery. This warranty is given only to the original retail purchaser, and this warranty is thus nontransferable. The prorated amount will be computed by dividing the number of months since the date the battery was purchased or installed as original equipment (as shown by the date on the customer repair order or parts counter ticket) by the number of months of proration shown on the battery and multiplied by the purchase price of the battery. A battery that fails under the New Vehicle Basic Limited Warranty will be replaced with a Mopar battery of equal or next highest amp-hour rating. WHAT IS NOT COVERED: Batteries that are discharged are not considered defective.

It is confusing. :)
You're not likely to find it posted anywhere. It is instructions from FCA to the dealers on how to handle warranty claims for batteries. Basically, it is to charge the batteries, and then put them on a load tester. If a battery fails the test, it gets replaced. If not, you are sent on your way with charged batteries. They have to follow the steps and report the results in the FCA diagnostic system. If they don't do it properly, they don't get approval for a warranty replacement. If they do a replacement without approval from FCA, they don't get paid for it. There is no trust and manager discretion like you may find at the auto parts store.
 

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It's absolutely crazy to think that Jeep accepts a battery at 60-70% charged as being ok, and that it will last, or that it's ok for a truck to have a battery that won't start the vehicle after only a week. These should be able to sit for a month and still start.

Anyone can Google words like AGM battery percentage of charge or AGM battery charge chart or words to that effect. There are variations in part to the different battery brands and the sources - it's not like conventional wet lead acid batteries where the numbers have been known and accepted for 50 years (or more) but the bottom line is these are sitting with a battery only sort of charged. I should be able to drive this truck, park it, open the hood and find the batteries at 12.6+ volts, no excuse, no exception. If it's not happening then the batteries are not accepting a charge or Jeep has something in the circuit that is preventing full charge.
These alternators are kicking out a voltage more than capable of fully charging a battery.

The optimal absorption voltages for AGM batteries are between 14.2V and 14.9V.
The actual charging voltage for the bulk of the work is lower than that.
Float voltages specified for 12V AGM batteries are between 13.2V and 13.8V (that's maintenance voltages)
Somewhat tangential, but my JTR sat at Toledo for two months, then at the trail head here in NM for a month. When I got it the battery was at 12.0. I charged it that night and it's at about 12.6 most of the time. Did you Overland sit on the lots for a length of time? And my ESS hasn't worked for weeks, which is fine by me. I'm waiting to take it in for my first oil change.
 

Andy29847

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You're not likely to find it posted anywhere. It is instructions from FCA to the dealers on how to handle warranty claims for batteries. Basically, it is to charge the batteries, and then put them on a load tester. If a battery fails the test, it gets replaced. If not, you are sent on your way with charged batteries. They have to follow the steps and report the results in the FCA diagnostic system. If they don't do it properly, they don't get approval for a warranty replacement. If they do a replacement without approval from FCA, they don't get paid for it. There is no trust and manager discretion like you may find at the auto parts store.
I just heard from my dealer. He says both batteries tested good. He also says that in my situation, where stop/start is disabled- batteries charging message constantly, the drill is to replace the IBS sensor. I’ll post more info if the fix does not work.
 
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ShadowsPapa

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I'm looking for the criteria. I haven't found it yet, but I found this:

MOPAR® AND MAGNETI MARELLI OFFERED BY MOPAR REPLACEMENT BATTERY LIMITED WARRANTY Batteries found to be defective in materials or workmanship will be replaced at no charge for the part-specified free replacement period from the date of purchase, as noted below. Batteries installed on an FCA US LLC vehicle covered by the New Vehicle Basic Limited Warranty, which are found to be defective, are warranted for the remainder of the New Vehicle Basic Limited Warranty, or within the free replacement period, whichever is more favorable to the customer. If the vehicle is equipped with a prorated warranty battery (not all batteries include a prorated warranty, see the top of the battery for warranty details), the owner may receive a prorated allowance toward the purchase of a new Mopar® or Magneti Marelli Offered by Mopar replacement battery. If the vehicle is not equipped with a prorated warranty battery, is no longer covered by the New Vehicle Basic Limited Warranty, and the free replacement period for the Mopar and Magneti Marelli Offered by Mopar Battery Warranty has expired, the owner may receive a prorated allowance toward the purchase of a new Mopar or Magneti Marelli Offered by Mopar replacement battery. This warranty is given only to the original retail purchaser, and this warranty is thus nontransferable. The prorated amount will be computed by dividing the number of months since the date the battery was purchased or installed as original equipment (as shown by the date on the customer repair order or parts counter ticket) by the number of months of proration shown on the battery and multiplied by the purchase price of the battery. A battery that fails under the New Vehicle Basic Limited Warranty will be replaced with a Mopar battery of equal or next highest amp-hour rating. WHAT IS NOT COVERED: Batteries that are discharged are not considered defective.

It is confusing. :)
The test sequence and criteria for Jeep batteries for warranty is extremely specific.
No individual could meet their test criteria unless you have a lot of money - and network connectivity to Jeep.
The equipment down to the model is specified by Jeep.


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He also says that in my situation, where stop/start is disabled- batteries charging message constantly, the drill is to replace the IBR sensor.
Well............. that may be THEIR drill, but it's not what is actually recommended.
IBS RESET is what should be tried first.

This is in a STAR communication to dealers - they are saying replace only if there's a DTC present for the IBS.

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Note 'What defines an IBS failure" - it appears as if the dealer won't be reimbursed for a replaced IBS under warranty if there's not a clear and present fault.
 

Andy29847

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This is in a STAR communication to dealers - they are saying replace only if there's a DTC present for the IBS.

1666721762443.png


1666721822959.png


Note 'What defines an IBS failure" - it appears as if the dealer won't be reimbursed for a replaced IBS under warranty if there's not a clear and present fault.
I got my Jeep back from the dealer today. They replaced the IBS sensor (warranty work). This is how it was documented.

i-Z6vM9fG-X4.jpg


The stop/start was still not working when I drove home. The service manager didn't mention that (I had some other work done). If they really replaced the IBS sensor, I think it will be a few days before the sensor begins to function (5 key on/off with 8 hours off in between?). I'll give it a few days and see what happens. BTW, the message center voltmeter showed 14.2v all the way home. I think I read somewhere that is a default voltage while the sensor completes the setup process.

I am late to the JL battery game. Youse guys and gals that were pathfinders have my respect. I do not think they could have devised a more complicated system. It reminds me of the transger case shift linkage from my TJ. :)
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