Your battery voltage - truck off and at rest

[Gatorized]

Based on the meta info in the pics (and the file names), I put the charger on at 12:08 today.
The charger was in completion mode, constant 12.7 volts, amperage ramping down by 3:50 pm, about 4 hours later. So it was basically done. It's in rest mode now, sitting charged 100%, voltage at 12.7 volts. So it didn't really take all that long to get a full charge, and that's both batteries since when the truck is off and sitting, they are connected together in parallel.

Is your voltage meter giving the same readings as the dash display?

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[ShadowsPapa]

Is your voltage meter giving the same readings as the dash display?

I haven't put the key in run position to look while charging or using the FLUKE to measure voltage.......
I wanted to not disturb or wake any sleeping systems.

 

[Junker21]

So now this is getting really silly. Drove the truck around picking up plywood on Tuesday.
(1/2 sheet of 1/2" and 1/2 sheet of 3/4" - 100 bucks)

The truck sat unused Wednesday and Thursday. This is Friday - this AM I took the truck to Altoona for some supplies (damn sparrows), that's all but 12 miles each way. It was 37 degrees out.
Auto stop/start not ready, battery charging - and - voltage a fairly solid 14.7 all the way up (almost 12 miles) AND all the way back - another almost 12 miles. So I'll call it 23 miles round-trip.
23 miles, 14.7 volts, not ready, battery charging. That makes ESS pretty much dead for ordinary drivers.

Ah, but wait, there's more! I checked battery voltage when I got back! That's 20 minutes driving up and 20 minutes driving back, 23 miles total. This is after I got back - Put on the reading glasses, that's 12.2 (TWELVE POINT TWO) Volts AFTER 40 minutes of driving.
No, I didn't check it before I left, really wish I had)

Now what's the state of charge on two batteries sitting in parallel at 12.2 volts?

Try 48% according to this (and some charts as well)
Reading glasses again ->

So, before I even left the garage, the batteries were UNDER 50% and most likely well under 12.2 volts since that 12.2 is after returning home, driving 2 times 20 minutes (23 miles)
You're telling me that a 240 amp alternator running 14.7 volts can't keep these tiny batteries charged?
And - that sitting 2 days drains 50% SoC off the top?

It appears that after charging both batteries twice - independently each time, reconnecting them, charging again, and driving it around and things are fine, that once it sits for a day, things go down the toilet.
The goofy thing is that the sort of voltage applied, and the 240 amp capability of an alternator can't keep up with use, or, these things aren't truly ever being totally charged.......... is that right?
And that sitting, either the batteries are so bad that they drop 50% in 2 days, or there's such a huge drain somewhere that empties them as it sits..................
I give it another few days then I contact a different dealership and show them everything that's been done, all measurements, checks, battery charges and so on.

So I thought your battery charger looked familiar , thought maybe a knockoff . I checked Napa
and it's a rebranded Pro-Logix PL2320 by Clore automotive . Iv'e had mine for at least 5 years
and it's awesome ! Shows SoC and conditions batteries and works as a Tender .
Now on sale at Napa , $89 . Pro-Logix $108 at Amazon .

The day after the dealer replaced the aux here's my reading after an overnight.

At that charge it took half hour of driving around for ESS to start working . Never has said
"charging " just "not ready" . Charged it overnight to 100% , 12.8 and ESS kicked in within a mile
of leaving the house .

Also I wanted to size the main battery was .

Look at the bottom right corner of the left label .
Limit Charge Voltage to 14.4 Max . Only for Plug in charging or also alternator output ?
I'm curious if your label also gives that warning .
The label doesn't show a group size that I know of . All I've heard mentioned is group 48 or
H7 . Any way at 650 CCA it is the smaller one .

 

[ShadowsPapa]

Must be slightly different chargers - it was 140 on sale. There are several variations on it - some are 6/12v, some are 12/24, some are 10 amp, some are 20 amp.
If it's on sale for that price, that's almost 40% off.
The controls on mine, even the lights, are nearly identical.
I was looking at another they had on the shelf and the guy was looking up prices for it and said - there's a newer replacement out for a couple bucks cheaper if you want that. I said I wanted the newest model.

I need to check what the battery says, if anything.
It's weird that the truck will read 14.7 volts if the battery says limit charging to 14.4.
I still suspect there's some bad programming in these as far as charging rates and the SoC measurement the PCM is going by. I wonder if they "imported" the stuff they had from prior generations and other batteries and never bothered to update things.
On the other hand, I've never seen AGM that said to limit voltage that low! Even the battery charger beats 14.4 volts, as does my truck.
IMO, Jeep has a problem. AGM are better batteries, so why are they replacing them at what is probably the quickest pace in Jeep history?
Why are so many owners reporting low voltages - there's not an AGM battery I've been able to find that is even half charged at 12.19 volts. And yet that's a pretty common number out there.

 

[Junker21]

Must be slightly different chargers - it was 140 on sale. There are several variations on it - some are 6/12v, some are 12/24, some are 10 amp, some are 20 amp.
If it's on sale for that price, that's almost 40% off.
The controls on mine, even the lights, are nearly identical.
I was looking at another they had on the shelf and the guy was looking up prices for it and said - there's a newer replacement out for a couple bucks cheaper if you want that. I said I wanted the newest model.

I need to check what the battery says, if anything.
It's weird that the truck will read 14.7 volts if the battery says limit charging to 14.4.
I still suspect there's some bad programming in these as far as charging rates and the SoC measurement the PCM is going by. I wonder if they "imported" the stuff they had from prior generations and other batteries and never bothered to update things.
On the other hand, I've never seen AGM that said to limit voltage that low! Even the battery charger beats 14.4 volts, as does my truck.
IMO, Jeep has a problem. AGM are better batteries, so why are they replacing them at what is probably the quickest pace in Jeep history?
Why are so many owners reporting low voltages - there's not an AGM battery I've been able to find that is even half charged at 12.19 volts. And yet that's a pretty common number out there.

Yes the Napa is regular $144 now $89
even same part # as Pro-Logix (C)PL2320 . Good deal on a great charger .
My charger topped out at 14.4 today .
The battery was at 12.5 , 75%.
Seems to take a long time from 97%
to 100% .

 

[ShadowsPapa]

Yes the Napa is regular $144 now $89
even same part # as Pro-Logix (C)PL2320 . Good deal on a great charger .
My charger topped out at 14.4 today .
The battery was at 12.5 , 75%.
Seems to take a long time from 97%
to 100% .

I haven't solidly timed it but when mine was under 50% it took under 4 hours.
Once it hits 100% it can take a couple of hours to end the process and shut down.
I'm not sure what you are looking at for part number but mine is CBC612V20A and is still $140

Part #: SOR CBC612V20A

 

[Junker21]

I haven't solidly timed it but when mine was under 50% it took under 4 hours.
Once it hits 100% it can take a couple of hours to end the process and shut down.
I'm not sure what you are looking at for part number but mine is CBC612V20A and is still $140

Part #: SOR CBC612V20A

Just checking the napaonline.com website. I see your model listed after a long scroll. Anyway Napa's website sucks , slow and clunky and hard to search in my experience. YMMV.

 

[ShadowsPapa]

Oh, boy. Hooked up with both AlfaOBD and with JSCAN and found they were saying that the battery voltage was 12.0
At one point with ignition on to check things over, it was saying battery voltage was 11.87
That makes sense - pushed the button twice to get into run mode with engine off so there was more load like HVAC and radio and so on.
So I opened the hood and put my fluke on it - 12.0 volts
Hooked up battery charger - 12.0 volts, 25% charged.
Seriously? Not even sitting a week and it's at 25% charge and only 12.0 volts?
Yup - here it is, 25% At that rate it would be dead in less than a week.

JSCAN doesn't do any logging so I wasn't able to see anything like the vehicle saying what the state of charge is, or anything like that.
AlfaOBD didn't show anything either - I'm a novice with those so maybe there's a way to see data like battery state of charge and voltages and such (I need to go to class)

And then JSCAN kicked THIS at me...... Obscure as heck. AlfaOBD said NO errors anywhere, and this was after a JSCAN "deep scan".

 

[Kevin_D]

So the Gladiator sat all of April and most of May. When I went to use it the last week of May, there was no response: both batteries were drained (I didn't measure the voltage.) I put it on a 10A charger for a couple of hours, and it started without a problem, but the ESS showed Not Ready: no other message, simply Not Ready. A few 10-15 minute drives, and the ESS was still Not Ready.
I took two 45-minute drives, and still Not Ready on the ESS (other messages, like Engine Temp. Too Low, Driver's Seat Belt Not Fastened, etc., displayed as expected.) I measured ~12.6V on both batteries.
I put it on a 1-2A slow charge for 48 hours, and went for a drive. The ESS showed Ready once temperatures stabilized, and worked as expected.
After sitting for 24 hours, the main battery measures 12.8V, and the aux. measures 12.75V.

Now, after draining the batteries, I suspected that the auxiliary battery might be shot, but after the short boost charge and a couple of short drives, the Jeep would start with just the aux. battery, so it still had plenty of capacity.
Since the ESS has worked flawlessly until this point, I've no reason to suspect that the battery voltage will drop to 12.6V with normal driving (short trips 2-3 times a week.)
I do find it unusual that the charging system in the vehicle didn't seem to be up to the task of raising the battery voltage from ~12.6V to ~12.8V with 2 drives of 45 minutes at highway speeds.

Kevin

 

[ShadowsPapa]

So the Gladiator sat all of April and most of May. When I went to use it the last week of May, there was no response: both batteries were drained (I didn't measure the voltage.) I put it on a 10A charger for a couple of hours, and it started without a problem, but the ESS showed Not Ready: no other message, simply Not Ready. A few 10-15 minute drives, and the ESS was still Not Ready.
I took two 45-minute drives, and still Not Ready on the ESS (other messages, like Engine Temp. Too Low, Driver's Seat Belt Not Fastened, etc., displayed as expected.) I measured ~12.6V on both batteries.
I put it on a 1-2A slow charge for 48 hours, and went for a drive. The ESS showed Ready once temperatures stabilized, and worked as expected.
After sitting for 24 hours, the main battery measures 12.8V, and the aux. measures 12.75V.

Now, after draining the batteries, I suspected that the auxiliary battery might be shot, but after the short boost charge and a couple of short drives, the Jeep would start with just the aux. battery, so it still had plenty of capacity.
Since the ESS has worked flawlessly until this point, I've no reason to suspect that the battery voltage will drop to 12.6V with normal driving (short trips 2-3 times a week.)
I do find it unusual that the charging system in the vehicle didn't seem to be up to the task of raising the battery voltage from ~12.6V to ~12.8V with 2 drives of 45 minutes at highway speeds.

Kevin

And that's what has got me wondering about how the charging is actually controlled.
With my smart charger, which goes through multiple stages - controlling amperage, then controlling voltage, and so on, it charges the batteries fine - but takes more than a couple of hours to do it right.
My aux battery took around 2 hours to charge to 12.78 volts, 100% by itself, the crank battery took most of the day to charge fully by itself.
Then I went for a drive and in 1.25 miles, ESS worked at the 2nd stop sign and worked all day fine.
The truck isn't properly charging these for some reason.

 

[Xtream1]

...
I do find it unusual that the charging system in the vehicle didn't seem to be up to the task of raising the battery voltage from ~12.6V to ~12.8V with 2 drives of 45 minutes at highway speeds.

Kevin

I've had both batteries changed by the dealer due to them failing about 2 months ago (2020 rubicon launch auto with ~45k miles driven daily). Today I happened to turn on the dash voltmeter and noticed that under power it was reading under 12.9 volts regardless of RPM (idle or driving didn't matter). But, during driving, when I let off the gas and coasted, the gauge climbed to above 14 volts. It appears as though when using the natural deceleration of the engine, it raises the dash voltmeter to the 14+ volts that I would expect to see during engine reving. Might be why we are having issues. If it's only getting full boost charging during deceleration and not during engine load, it's not really getting charged properly as I expected. Even at idle, 12.8-12.9 volts. AGMs need a much higher level to fully charge but I don't know where the reading is being taken from (may not matter though).

 

[Mister Lamb]

@ShadowsPapa, have you considered pulling accessory fuses in order to find the culprit behind the battery drain? Here on the job our Ford Escape kept dying with a relatively new battery due to the radio sucking the battery dry whether in the on/off position.

 

[jebiruph]

I've had both batteries changed by the dealer due to them failing about 2 months ago (2020 rubicon launch auto with ~45k miles driven daily). Today I happened to turn on the dash voltmeter and noticed that under power it was reading under 12.9 volts regardless of RPM (idle or driving didn't matter). But, during driving, when I let off the gas and coasted, the gauge climbed to above 14 volts. It appears as though when using the natural deceleration of the engine, it raises the dash voltmeter to the 14+ volts that I would expect to see during engine reving. Might be why we are having issues. If it's only getting full boost charging during deceleration and not during engine load, it's not really getting charged properly as I expected. Even at idle, 12.8-12.9 volts. AGMs need a much higher level to fully charge but I don't know where the reading is being taken from (may not matter though).

This appears to be normal operation. The point of the smart alternator is to reduce engine load and increase mpg when higher alternator output is not needed. When you are decelerating, they can increase the alternator output without increasing mpg, it's free voltage whether you need it or not.

 

[Xtream1]

This appears to be normal operation. The point of the smart alternator is to reduce engine load and increase mpg when higher alternator output is not needed. When you are decelerating, they can increase the alternator output without increasing mpg, it's free voltage whether you need it or not.

This is exactly my point. Maybe there isn’t enough full voltage charge time in its factory set points. I would presume that the engineers got it right but with the trending battery failures it may be the source of the problem.
It would be great if the curves could be adjusted through a tazer or something similar.

 

[ShadowsPapa]

The PCM coupled with the IBS that handles the logic.
I'd love to have a chat with the guy who came up with the term "smart alternator" - it's laughable.
It's like saying a ventriloquist's dummy is smart because the guy controlling it is.
I fail to see how the alternator is "smart".
Anyway, in most modern vehicles, the alternator does what it does based on the field current or control current given it from the PCM. (looking at the configuration of my truck posted below - check the line that say "Smart alternator" and what it says about it........)
There's no logic, no fancy electronics, nothing different in them in the slightest.
They are controlled by the PCM. How is that smart?
Any alternator could be hooked up and the field controlled via PCM. Even the 1990s 4.0 system alternator was controlled by the PCM - except it was voltage regulated to a set voltage. These are varied - but by the PCM. So it's a smart system, a dumb alternator! Amazing how the auto people throw names out that imply the alternator itself has any brains or controls squat. There's nothing in them.
The PCM bases how IT controls what the alternator does based on the historical information from the IBS, which tracks everything going in and coming out of the battery. It tells the PCM the battery SoC, temperature, and historical data. The PCM determines what is needed.

I posted snips from the bulletin on how these work, the modes they go through, and how it's the PCM that controls it all using historical data the IBS supplied via the LIN.

Besides the green above, the purple describes how the PCM cuts fiend current to the alternator to reduce engine load during high RPM maneuvers - passing, needing power for a hill, heavy acceleration. It removes the parasitic load of the alternator by cutting field current, the alternator just costs, not loading the engine.
Trickle charge is used when the battery SoC is at or near 100%, under certain temperature conditions such as when the IBS tells the PCM the battery is hot and other factors.
It maintains electronics and keeps a minimum voltage to prevent further battery charging and heating. (Ideally this should help batteries in hot climates to last longer.)


Full Speed Range Forward Collision Warning Plus System: Yes
Type of adaptive Cruise Control (ACC) system present: ACC with stop
Transmission Equipped: Automatic transmission
Park Brake Type: Mechanical Park Brake - Hand or Foot
TPMS Configuration: Logic 1 NHTSA Enable Warning
Smart Alternator Present: No

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