Understanding the Dash voltage display for ESS, battery health

[jeepoch]

Thanks Jay, when I see 'battery voltage' I alarmingly believe the alternator has quit - it actually had not as you explain! Problem is the aux battery, even though new too is not receiving a charge...

Bill, give it some time, don't panic or overthink this. Yes, the Intelligent Battery Sensor (IBS) is also in the mix and requires some amount of time, usually a few good trips over a day or two, in order to relearn a new 'normal'.

However, as long as everything is connected tightly, there should be no concern. You should expect your voltage (actually alternator effort) guage to only rise into the mid 13's as some time ticks by. Of course, if you run with Electrical Start/Stop (ESS) enabled, or take extremely short trips between igntion cranks, then that will put a much higher stress on your batteries. If so, low to mid 14 readings will be the result.

Again, don't think of the 'Battery Voltage' guage as actually measuring terminal voltage, (unfortunately it really doesn't), think of it as a bar graph as indicating alternator output 'effort'. The higher the value, the harder your alternator is working at keeping your batteries fully charged.

It also takes adequate time (long enough drive) to keep things charged appropriately. Each and every engine start, no matter with the ignition switch at the beginning of a drive, or ESS events, either drains both batteries. The secret is to finding a way to allow the charging effort to keep up.

I routinely require plugging in my NOCO Genius 10 Battery Charger to help keep my system fully charged. But I'm the nutcase oddball who rather enjoys when the ESS shuts the engine off at red-lights. So keeping my batts fully charged, just from the alternator's effort, is nearly impossible.

If I don't frequently use a battery tender, then I frequently have to deal with the ESS "Battery Charging" and "Battery Protection Mode" complaints.

The JL charging system with it's assinine dual battery ESS design is woefully inadequate for normal city driving. If you really like ESS, then it's an absolute necessity to frequently plug in an external charger. Which does suck. However, other than the nag of babysitting at keeping my batteries charged, I'm having a blast with my lifted on 35's 2019 Sport. Best daily driver I've ever owned. If only the battery technology and charging capacity could just keep up with the way I drive this thing, then I'd truly have Jeeping nirvana. Oh well...

However I do like ESS, so I'm coping with it. To each there own.

Good luck with your JL charging experience. But again relax, it sounds (to me) you're going about this properly. Again if you don't like routine 14v readings, permenantly disable your ESS.

Best Regards,
Jay

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[YBABRAT]

After the battery change session yesterday, we saw the voltage go from 14.2 down, during the half hour drive, to 12.4V. Don't like that...appears the alternator has voltage sensing errors. How about the "IBS" (amazon 4692269AI) that is used in the Cherokee with ESS?? If that "Intelligent Battery Sensor" is defective it could cause issues with charging the secondary battery... Need to go look under the hood... Yes - it's on the negative main battery terminal and the secondary battery ground line appears to go 'through' it. So - that's where the battery isolation occurs for the alternator. Perko (for boat battery disconnect) switches have 'make before break' contacts to prevent multiple battery switching to prevent blowing diodes in the alternator.

As long as the IBS was correct for a factory AGM equipped Jeep vehicle, it should function.

Possible that your IBS mounting area needs cleaned... it has a ground pad at the base where it mounts to the terminal head. You will need to remove to clean. The best method to clean any contact point is a pencil eraser. It is not so abrasive and will clean very well.

Anything abrasive will create scratches which will lessen the full contact area and allow condensation to weep into. Which corrosion or contanaments will limit contact over time.

I partially cleaned mine to save for demonstration on my posted thread. Haven't yet gotten to completing it to add pictures. None the less changing out an IBS will still require a look and possible clean up before mounting.

 

[WAC]

As long as the IBS was correct for a factory AGM equipped Jeep vehicle, it should function.

Possible that your IBS mounting area needs cleaned... it has a ground pad at the base where it mounts to the terminal head. You will need to remove to clean. The best method to clean any contact point is a pencil eraser. It is not so abrasive and will clean very well.

Anything abrasive will create scratches which will lessen the full contact area and allow condensation to weep into. Which corrosion or contanaments will limit contact over time.

I partially cleaned mine to save for demonstration on my posted thread. Haven't yet gotten to completing it to add pictures. None the less changing out an IBS will still require a look and possible clean up before mounting.

Thanks all! I have a short fuse with automobiles - always have. Usually goes off before logic kicks in. The system is working for the first time since we bought the Jeep! (now I can turn the ESS system off) but it WORKS! The mechanic said to take it home, park it and in the morning it will be back to normal - to my amazement and disbelief he was correct! Thanks for all the help and yes I'm still reading and taking in all I can from this forum!!

 

[AFD]

Anyone know what the normal/healthy operating voltage reading for an eTorque system is?

Iirc, when new, at the first start of the day it would quickly jump to around 14.5V for a while and then settle down a little lower during the drive (and on the second drive it would usually stay just below 14V).

After reading this thread this morning, I noticed my first drive stayed high the entire trip, from 14.8 up to 15V and not any lower. Ambient temps were ~20°F for the first time this winter, so was thinking maybe the system was pushing things higher than usual trying to recharge up the cold 48V Li-Ion suitcase battery, but honestly no idea how that shit works without a regular alternator (iirc, the BSG charges the 48V, which then charges the 12V AGM).

 

[YBABRAT]

Anyone know what the normal/healthy operating voltage reading for an eTorque system is?

Iirc, when new, at the first start of the day it would quickly jump to around 14.5V for a while and then settle down a little lower during the drive (and on the second drive it would usually stay just below 14V).

After reading this thread this morning, I noticed my first drive stayed high the entire trip, from 14.8 up to 15V and not any lower. Ambient temps were ~20°F for the first time this winter, so was thinking maybe the system was pushing things higher than usual trying to recharge up the cold 48V Li-Ion suitcase battery, but honestly no idea how that shit works without a regular alternator (iirc, the BSG charges the 48V, which then charges the 12V AGM).

If temps are around 20°F and below... the compensation to charge will be higher... as for what you see. It can stay in that range for around 30 minutes. That is what I have seen when cold temps make batteries difficult to charge.

Until battery reaches full charge voltages will lower and will float around a lower range than initially seen.

As for the 24v battery... I assume it's a Lithium. It has a DC to DC charging system that can charge the 24v battery within the 12.8v to 15.2v range.

 

[AFD]

If temps are around 20°F and below... the compensation to charge will be higher... as for what you see. It can stay in that range for around 30 minutes. That is what I have seen when cold temps make batteries difficult to charge.

Until battery reaches full charge voltages will lower and will float around a lower range than initially seen.

As for the 24v battery... I assume it's a Lithium. It has a DC to DC charging system that can charge the 24v battery within the 12.8v to 15.2v range.

Yes, it's Li-Ion afaik, which like phone batteries, probably loses it's charge in extreme cold (don't believe the coolant lines do anything to keep it warm when sitting overnight).

Anyway, on the ride home, the voltage stayed a little below 14V the entire time (~30 minute drive, still ~25F) and after parking and shutting the engine down the voltage reader showed 12.4 to ~12.6V, which should mean the stock AGM is still decent for now (in use for just over 2 years).

Kinda wish I would've paid attention to the voltage meter during the cold weather right after I got it, to better see what was normal for the eTorque system. I know the stock battery is known to be shit, but somehow I got nearly 13 years from the OEM Panasonic battery in my last daily driver before it started to crap out (mostly from not driving it after I bought the JL). Crazy, right?

 

[YBABRAT]

Yes, it's Li-Ion afaik, which like phone batteries, probably loses it's charge in extreme cold (don't believe the coolant lines do anything to keep it warm when sitting overnight).

Anyway, on the ride home, the voltage stayed a little below 14V the entire time (~30 minute drive, still ~25F) and after parking and shutting the engine down the voltage reader showed 12.4 to ~12.6V, which should mean the stock AGM is still decent for now (in use for just over 2 years).

Kinda wish I would've paid attention to the voltage meter during the cold weather right after I got it, to better see what was normal for the eTorque system. I know the stock battery is known to be shit, but somehow I got nearly 13 years from the OEM Panasonic battery in my last daily driver before it started to crap out (mostly from not driving it after I bought the JL). Crazy, right?

Your over thinking noticing about charge right after ownership. From what you are seeing is good. The eTorque should not have any effect on main battery charge. Unless the generator starts to fail. 12.6v to 12.4v in very cold weather is normal. Reason being main part of capacity is between 12.1v to 12.6v, when under loads higher than 10A. Unlike the flooded cell, where capacity under load can reside around 11v to 12.4v.

Thinking old school about capacity with an AGM is not a good thing. It has a narrower under load voltage range that should not be ignored.

Allowing an AGM to deplete beyond 12.1v at any temp will shorten its life and capacity. If anything during cold weather or in long term non-use, as battery maintainer for AGM will keep the battery stable for many years... some have 10 years or more with such use.

My Jeep is a daily commute driver, yet our weather is getting colder as well, and I just might use my maintainer every weekend very soon.

Remember AGM capacity will be lower when temps are low. One reason why I modified to run a single H8 sized AGM. An Odyssey H7 battery is top notch if your oem should become problematic. I chose a Walmart AGM due to price and they are just about everywhere and warrenty exchange is one of the best.

 

[AFD]

Your over thinking noticing about charge right after ownership. From what you are seeing is good. The eTorque should not have any effect on main battery charge. Unless the generator starts to fail. 12.6v to 12.4v in very cold weather is normal. Reason being main part of capacity is between 12.1v to 12.6v, when under loads higher than 10A. Unlike the flooded cell, where capacity under load can reside around 11v to 12.4v.

Thinking old school about capacity with an AGM is not a good thing. It has a narrower under load voltage range that should not be ignored.

Allowing an AGM to deplete beyond 12.1v at any temp will shorten its life and capacity. If anything during cold weather or in long term non-use, as battery maintainer for AGM will keep the battery stable for many years... some have 10 years or more with such use.

My Jeep is a daily commute driver, yet our weather is getting colder as well, and I just might use my maintainer every weekend very soon.

Remember AGM capacity will be lower when temps are low. One reason why I modified to run a single H8 sized AGM. An Odyssey H7 battery is top notch if your oem should become problematic. I chose a Walmart AGM due to price and they are just about everywhere and warrenty exchange is one of the best.

Good points, thanks! And yeah, I'm okay with having another OEM battery last me over a decade - or replacing it early with something better. The only thing I'd like to avoid is having it crap out early and when I really need it (cold winter morning before work), especially if there were signs I didn't notice when changing it would be more ideal (nice sunny summer weekend, lol).

Think I'll just pay more attention to the meter on a more regular basis and remember what's "usual" and hopefully notice if the voltage suddenly seems irregular for the season. Never had a "mild hybrid" before, so that part of the equation is still new to me.

 

[YBABRAT]

Good points, thanks! And yeah, I'm okay with having another OEM battery last me over a decade - or replacing it early with something better. The only thing I'd like to avoid is having it crap out early and when I really need it (cold winter morning before work), especially if there were signs I didn't notice when changing it would be more ideal (nice sunny summer weekend, lol).

Think I'll just pay more attention to the meter on a more regular basis and remember what's "usual" and hopefully notice if the voltage suddenly seems irregular for the season. Never had a "mild hybrid" before, so that part of the equation is still new to me.

I would be more concerned about the eTorrque battery over a few years time, than the AGM. It's an odd setup that is somewhat new.

You're lucky you don't have ess dual battery system. It is problematic by its design. The only option to rid the issues is to forego the Aux battery for a single battery setup.

Yep, you'll get the knack on monitoring.

 

[AFD]

I would be more concerned about the eTorrque battery over a few years time, than the AGM. It's an odd setup that is somewhat new.

You're lucky you don't have ess dual battery system. It is problematic by its design. The only option to rid the issues is to forego the Aux battery for a single battery setup.

Yep, you'll get the knack on monitoring.

Maybe luckily unlucky

While it's nice not having the tiny secondary battery, at least that can easily enough be replaced or bypassed. Not so much for the Li-Ion suitcase, since that's the only means of keeping the AGM charged. Even if swapping the BSG to an alternator wasn't an issue, I'm sure the way it's wired would be a nightmare to change, and that's not even factoring in the 48V cooling system and trying to find an ECU that doesn't try to do things like brake regen and other MHEV shit. It's a neat idea, I guess, but unnecessarily complex with very little benefit (Hey Jeep: K.I.S.S!)

Always thought it was weird that there wasn't a specific gauge, meter or info panel to view the current status of whatever tf that thing's doing.

 

[YBABRAT]

I would be more concerned about the eTorrque battery over a few years time, than the AGM. It's an odd setup that is somewhat new.

You're lucky you don't have ess dual battery system. It is problematic by its design. The only option to rid the issues is to forego the Aux battery for a single battery setup.

Yep, you'll get the knack on monitoring.

There is a lot of data within the can bus, and I would think after market would produce a monitor for eTorque. Either a phone app or stand-alone.

One way to get the feature you want with main battery is at a later time when you will have to replace the main battery. Antigravity has a smart drop in LifePO4 battery. It has Bluetooth tech to allow monitoring of its status and enable boost mode for cold weather starting.

There is a LifePO4 made for sub zero use with its own internal heater. Unfortunately I lost the link and the manufacturer's name escapes me.

Though I believe by the time you and I will be replacing our AGM batteries, there will be a stronger LifePO4 base for drop in upgrades to update to new tech battery systems. A big reason why I did not buy an expensive battery this year. As I am willing to wait it out for better options and prices to level out.

 

[melendez69]

I usually only drive my JL on weekends & long trips, and when it's gonna sit for over 2, 3 days, I keep a NOCO 10 on the batteries. Initially, when it started about 13.6, 14.2, it would eventually drop to where I expect it, around 12.8. For the past week, it would start around 12.8, then 13.6. Recently it started about 14.4 & just hang out there.... and sometimes rise to 14.6.

I installed the Genesis dual battery kit in May of 2021 and since it's been about 3.5 years, I figured it's time to replace the batteries (done today, by the way).

The older batteries showed somewhat similar results, but 'replace' for the cranking battery (12.82), and 'good' for the accessory battery (12.8) with low states of health.

I wonder if I'm charging them too frequently.

 

[Leonards24JL]

This is a great thread with a lot of info!

I need some of the experts here to help out. I bought a 24 sport s in May and currently have arbitration date next week pursuing buyback. It had to be put in the shop after two months because it said to pull over the car was going to shut down. The problem was the charging system and they replaced the batteries the first time. Replaced the batteries and alternator the second time as well as reflash PCM. Same again the third time but this time replaced PCM and again the fourth time. The fourth time it was in the shop for 1.5 months and I was able to get my hands on the stars case info. The issue was the car was overcharging the batteries and the PCM was telling the computer to shut the car down (their explanation).
During the fourth trip the resolution was to cut the wires at the alternator and direct wire them from the plug at the pcm as well as add an additional ground. Previous to this the car would charge at 15.1 when the pcm told it to shut down. Within a week of picking it up it was registering 14.9 on the guage while driving (had been driving for about 30 mins so battery should not have been week) so I took it back. The jeep never threw a code so really not sure what I expected. Now I have it back and yesterday noticed it hit 15.0.
Now I am not engineer but I have worked on my own cars and motorcycles for years. I am wondering if the solution to cut wires has somehow bypassed the engine throwing a code. I would love some feedback or thoughts on this as well as does anyone ever see 15.0 charging????

For info the dealership has been awesome to work with which I know is rare. Looking at some of the notes you can see the tech is very frustrated with the Stars people.

 

[jeepoch]

@Leonards24JL

PHil, there's literally no way to accurately troubleshoot your vehicle without being there, but we can perhaps work in some amount of theory based on your description.

First, the Engine Controller determines the amount of total charging 'effort' based upon the dynamic electrical load of the entire system. This includes the current draw of everyting turned 'on' within the whole vehicle. The alternator (or generator's) output must equal all that 'plus' even more energy (in amps) to charge the batteries.

Second, if the batteries are being 'over-charged', then we can assume that your electrical system has a high impedence short circuit somewhere. Not a direct enough short to make something overheat and/or blow a fuse but enough to create an unusually high system load.

So the attemp to rewire things is basically a shotgun attempt to byass said short.

There's not many things that can create such a load without getting hot, unless whatever is drawing this current is able to sufficiently dissipate it and remain cool enough to remain hidden.

Have you or they tried removing fuses to shut certain systems down and see what effect is has on the alternator's output? I would start with the obvious components such as AC Compressor, fans, lights etc. If you remove a fuse and the output drops significantly (a half volt or more) you have a clue.

If no success, has the alternator been diagnosed for having the correct manufacturer's specifications? Could it have been made with an incorrect inductance (improper number of windings of conuctors at the primary core)? In other words, is this particular alternator supplying too much energy for a given PCM command input?

Have they replaced both batteries? Any dead cell on either battery could indeed be the culprit. This cannot generally be simply determined with a voltage measurement. Both batteries (independently) must be load tested seperately.

I've never (ever) seen my 2019 JL Sport 3.6L battery (alternator) voltage guage go over 14.7v. And I've replaced several sets of weak batteries over the years.

If they are willing, or even consideing, a buy-back of this particular unit, I'll suspect that they've tried all the things that I've suggested. I used to work as a Software Engineer for a major automotive company, implementing Engine Controller firmware. In my experience, corporate would generlly send out an engineering team to help diagnose issues prior to any buy-back. However, in today's economy, this may no longer be an option. Poor Joe Schmoe dealership dude may be stuck trying to figure this out with minimal support. In fact based on your post, this is indeed highly likely.

Sorry I can't be more helpful. But hopefully this gives you more information to consider.

Good luck, best wishes,
Jay

 

[WranglerMan]

I usually only drive my JL on weekends & long trips, and when it's gonna sit for over 2, 3 days, I keep a NOCO 10 on the batteries. Initially, when it started about 13.6, 14.2, it would eventually drop to where I expect it, around 12.8. For the past week, it would start around 12.8, then 13.6. Recently it started about 14.4 & just hang out there.... and sometimes rise to 14.6.

I installed the Genesis dual battery kit in May of 2021 and since it's been about 3.5 years, I figured it's time to replace the batteries (done today, by the way).

The older batteries showed somewhat similar results, but 'replace' for the cranking battery (12.82), and 'good' for the accessory battery (12.8) with low states of health.

I wonder if I'm charging them too frequently.

I just replaced the batteries in my Genesis Gen 2 system after 4 years as I started having issues like remote start not working, key fob not detected so at the time I did not have a battery tester so had them tested at several places and even though they charged fine thry had low CCA’s at 220 and they were rated for 750 and resistance was high, I was advised they were likely shorted and had bad cells.

I was told by a member here that the Full River batteries in my case were over charged, I to put them either on a NOCO 10 or Odyssey 20 smart charger 4-6 times a month so now unless its going to be parked for weeks on end I will only charge them once a month in cold weather with the NOCO and maybe quarterly during the winter months.

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