Your battery voltage - truck off and at rest

[Maximus Gladius]

I have not tried to isolate the batteries to get independent voltage checks.
Charging systems up through the 90s are more my specialty so I'm still learning.
I've done literally hundreds of 'em but all before 2000.
As we have two Jeeps and likely always will - this is not only a quest to get mine resolved/fixed/figured out, I want to know as much as possible for the future and moving forward.
Anyway, I'll check voltage again tonight, then in the AM and keep monitoring it and see if I see any pattern as well.
I may try to get independent voltage measurements as well as resetting the IBS.


(my alternator and starter cores)

My wife has a closet of shoes stacked in such fashion. She keeps telling me she doesn’t have any shoes, or can’t find them.
I see you suffer from something very similar.

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[DobaMark]

What are the 12 enabling requirements? All I ever see is engine temp too low, cabin heating or cabin cooling. After that it's Not Ready or Ready and that's it. Is there anywhere I can look up these enabling requirements?

The 2020 owners manual lists these (more than 12):

• Driver’s seat belt is not buckled
• Driver’s door is not closed
• Battery temperature is too warm or cold
• Battery charge is low
• The vehicle is on a steep grade
• Cabin heating or cooling is in process and an acceptable cabin temperature has not been achieved
• HVAC is set to full defrost mode at a high blower speed
• HVAC set to MAX A/C
• Engine has not reached normal operating temperature
• Engine temperature too high
• The transmission is not in a forward gear
• Hood is open
• 4WD system is put into 4L or Neutral
• Brake pedal is not pressed with sufficient pressure

Other Factors:

• Accelerator pedal input
• Vehicle speed threshold not achieved from previous auto-stop
• Steering angle beyond threshold
• ACC is on and speed is set
• Vehicle is at high altitude
• System fault present

And the reasons the vehicle may restart after stop:

• The transmission selector is moved out of DRIVE
• To maintain cabin temperature comfort
• Actual cabin temperature is significantly different than temperature set on Auto HVAC
• HVAC is set to full defrost mode
• HVAC system temperature or fan speed is manually adjusted
• Battery voltage drops too low
• Low brake vacuum (e.g. after several brake pedal applications)
• Stop/Start OFF switch is pushed
• A Stop/Start system error occurs
• STOP/START AUTO STOP ACTIVE time exceeds 5 minutes
• 4WD system is put into 4L or Neutral mode
• Steering wheel is turned beyond threshold

 

[DobaMark]

So after three times charging (rapid charge at the dealer, plus two trickle charges at home) my display now shows 12.4 after sitting on the cluster. And the stop/start is ready and working now after the last three days.

 

[ShadowsPapa]

I decided to reset the IBS today. Voltage had dropped to 12.31 from 12.5 last night and that's after driving it a bit yesterday AM. Not bad, not bad at all, really - low, IMO, but the fact that it took only a short time with the battery tender to get it back to 12.7 was not only baffling, but made me think of some progress. It's staying a bit higher than it was.

Resetting the IBS is simple - you take it out of the circuit. You remove power to it and wait something like 5 to 10 minutes.
I decided while in the process, I'd clean connections, too. Can't hurt as it's 2.5 years old and it's been in all sorts of weather and salt and water and spray and cold and hot and oxides take only seconds to set in under some conditions.

It will be very interesting now to see how it behaves with a full IBS reset, cleaning and putting things back. I wanted to wait a few minutes to check the voltage again. It takes, from what I've read, 8 normal start cycles (not remote start, etc.) and driving with about 8 hours in between each cycle for the IBS to re-learn. That means it likely won't be this week! It won't get driven Wednesday, Thursday or Friday as far as I know - unless my wife has other plans.

Being a very visual person, here's the pictorial -

This is the target, the IBS, that device clamped to the negative post of the main battery. The other cables are for body ground and are from the aux battery, etc. The smaller cable next to the yellow dipstick handle is the network cable that connects it to the network bus and thus the PCM ->

You first get a 10mm socket and take off the nut that holds the cable array to the top of the IBS - you can leave all the other stuff connected (ignore my fat black winch ground cable)
You then use that 10mm socket on the battery clamp part and the IBS lifts off.
Press the lock tab and you can slip the small connector off the IBS ->

I used the only insulating thing handy in my garage - an old rag to hold the cable off the negative battery terminal while I removed the IBS by lifting it straight up off the negative terminal, then unplugging the small cable.

And here's the IBS in all it's glory -

I decided to leave the battery clamp on it - that other nut is ungodly tight! Didn't want to break it and I saw no real reason to remove the clamp from the IBS itself ->

I did polish up the exposed copper and clean up inside the battery clamp and used some electric connector grease on the small network cable area.

 

[chorky]

The 2020 owners manual lists these (more than 12):

• Driver’s seat belt is not buckled
• Driver’s door is not closed
• Battery temperature is too warm or cold
• Battery charge is low
• The vehicle is on a steep grade
• Cabin heating or cooling is in process and an acceptable cabin temperature has not been achieved
• HVAC is set to full defrost mode at a high blower speed
• HVAC set to MAX A/C
• Engine has not reached normal operating temperature
• Engine temperature too high
• The transmission is not in a forward gear
• Hood is open
• 4WD system is put into 4L or Neutral
• Brake pedal is not pressed with sufficient pressure

Other Factors:

• Accelerator pedal input
• Vehicle speed threshold not achieved from previous auto-stop
• Steering angle beyond threshold
• ACC is on and speed is set
• Vehicle is at high altitude
• System fault present

And the reasons the vehicle may restart after stop:

• The transmission selector is moved out of DRIVE
• To maintain cabin temperature comfort
• Actual cabin temperature is significantly different than temperature set on Auto HVAC
• HVAC is set to full defrost mode
• HVAC system temperature or fan speed is manually adjusted
• Battery voltage drops too low
• Low brake vacuum (e.g. after several brake pedal applications)
• Stop/Start OFF switch is pushed
• A Stop/Start system error occurs
• STOP/START AUTO STOP ACTIVE time exceeds 5 minutes
• 4WD system is put into 4L or Neutral mode
• Steering wheel is turned beyond threshold

Wow thats a lot of conditions!!! Hmm. Maybe its time to remove the auz battery from the equation. I dont think in my area anyway all of those conditions will ever be met at the same time. Maybe only like 2% of the trucks life

 

[kahuna357]

The 2020 owners manual lists these (more than 12):

• Driver’s seat belt is not buckled
• Driver’s door is not closed
• Battery temperature is too warm or cold
• Battery charge is low
• The vehicle is on a steep grade
• Cabin heating or cooling is in process and an acceptable cabin temperature has not been achieved
• HVAC is set to full defrost mode at a high blower speed
• HVAC set to MAX A/C
• Engine has not reached normal operating temperature
• Engine temperature too high
• The transmission is not in a forward gear
• Hood is open
• 4WD system is put into 4L or Neutral
• Brake pedal is not pressed with sufficient pressure

Other Factors:

• Accelerator pedal input
• Vehicle speed threshold not achieved from previous auto-stop
• Steering angle beyond threshold
• ACC is on and speed is set
• Vehicle is at high altitude
• System fault present

And the reasons the vehicle may restart after stop:

• The transmission selector is moved out of DRIVE
• To maintain cabin temperature comfort
• Actual cabin temperature is significantly different than temperature set on Auto HVAC
• HVAC is set to full defrost mode
• HVAC system temperature or fan speed is manually adjusted
• Battery voltage drops too low
• Low brake vacuum (e.g. after several brake pedal applications)
• Stop/Start OFF switch is pushed
• A Stop/Start system error occurs
• STOP/START AUTO STOP ACTIVE time exceeds 5 minutes
• 4WD system is put into 4L or Neutral mode
• Steering wheel is turned beyond threshold

Thank you !

 

[ShadowsPapa]

Wow thats a lot of conditions!!! Hmm. Maybe its time to remove the auz battery from the equation. I dont think in my area anyway all of those conditions will ever be met at the same time. Maybe only like 2% of the trucks life

Those conditions prevent ESS from working. There's no way you'd ever meet them all at the same time anyway because engine too hot is in the list that PREVENTS ESS from working, and engine not up to temperature is in that list. So you can't be not up to temperature and too hot at the same time.

That list is simply reasons it may not stop the engine at a stop light. It's not a you have to meet these, it's if you meet any of these, it won't stop the engine.

But this is more about battery voltage, charging, it's not about ESS - that was just being used as an indicator that the "Truck" thought the batteries were low - and indeed they were way too low voltage-wise. ESS shouldn't even be in this since it's more of a gauge of battery state of charge and what the system believes to be true.

If your batteries are usually sitting at a low voltage, like 12.2 or less, they aren't fully charged and may suffer a shorter life. How will you know? ESS won't work. It's a tell, not the topic.

I find it really odd that mine - even with the batteries charged overnight, the cluster STILL reads voltage at 14.5+ volts while driving it. It never seems to deviate from the 14.xx volt area. That's too high for a fully charged battery.

The voltage readings make no sense. Mine was fully charged, I drove it yesterday, and it still was reading 14.6 volts much of the time - if the batteries are truly fully charged it should not be reading that high. But since it WAS reading 14.7 system volts almost the whole time the truck was in use - why were the batteries still not sitting at 12.7 or higher?

 

[chorky]

Those conditions prevent ESS from working. There's no way you'd ever meet them all at the same time anyway because engine too hot is in the list that PREVENTS ESS from working, and engine not up to temperature is in that list. So you can't be not up to temperature and too hot at the same time.

That list is simply reasons it may not stop the engine at a stop light. It's not a you have to meet these, it's if you meet any of these, it won't stop the engine.

But this is more about battery voltage, not ESS. Battery voltage, regardless of ESS.
If your batteries are usually sitting at a low voltage, like 12.2 or less, they aren't fully charged and may suffer a shorter life.
I find it really odd that mine - even with the batteries charged overnight, still runs at 14.5+ volts while driving it.
The voltage readings make no sense. Mine was fully charged, I drove it yesterday, and it still was reading 14.6 volts much of the time - if the batteries are truly fully charged it should not be reading that high.

according to the vehicle computer my voltage this morning was 12.3. But thats key on engine off so there is drop due to things running like fan radio etc - unless the BMS accounts for that.

i drove to work yesterday. Literally a 3 minute drive. Just flet lazy. So i think starting the jeep twice with super short drives hurt my voltage. I will try and remember to test battery voltage tonight with the meter.
but i found that interesting. Makes me wonder if theres some weird stuff going on that even the engineers dont understand Yet.

 

[jac04]

I decided to reset the IBS today.
...
It will be very interesting now to see how it behaves with a full IBS reset, cleaning and putting things back.

Just wondering, are you planning to charge each battery individually prior to re-connecting the IBS system?

 

[ShadowsPapa]

Just wondering, are you planning to charge each battery individually prior to re-connecting the IBS system?

I had thought about it - should be easy with the negative cables off the main battery.

 

[ShadowsPapa]

Just wondering, are you planning to charge each battery individually prior to re-connecting the IBS system?

Oddly with my little "tender" type chargers, it didn't take long at all for them to kick into maintenance mode and say each battery was fully charged.
I used the 1.5 amp on the main battery and the 800mA unit on the aux battery. The aux battery charged up first and the small charger went into maintenance mode (shut down, monitoring) and the other one continued to charge for another 45 minutes. Once they were both charged, I removed them and put the 1.5 amp charger on the aux battery - it charged for 20 minutes or so then kicked off (likely different voltage settings)
I checked the main at 12.79 volts after sitting with no charger on it for about 60 minutes
I checked the aux battery at 12.9 volts after sitting with no charger on it for about 5 minutes
I put the IBS back on and buttoned things up. Both batteries independently fully charged.
Will be interesting...................

 

[Erievon]

So to change the aux battery alone with the trickle charger, positive to which stud on the fuse block, and where do I go with the negative?​

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[ShadowsPapa]

Just take the cables off the top of the ibs. You can leave the two cables together. Keep them off the main bat neg post and connect the charger to the neg cables you lifted off the ibs
Connect to where my winch ground is in pic above.

 

[chorky]

Just checked voltage. 12.63 this time. that's 2 days of driving to work and back for a VERY short 3 minute drive. Why is why I usually walk.k. Anyway I also noticed, because you mentioned it above, that the computer stated charging level was 13.3v +/- But nowhere near the 14.something you were getting.

This was with a 8 minute warmup in the driveway though. Today I actually had 4 startups. The longest drive at lunch was about 10 minutes maybe. Probably more like 7.

Really interested in seeing how your voltages look tomorrow and through the weekend. Maybe you fixed the problem with the reset - sure hope so.

 

[jac04]

Just take the cables off the top of the ibs. You can leave the two cables together. Keep them off the main bat neg post and connect the charger to the neg cables you lifted off the ibs
Connect to where my winch ground is in pic above.

That makes sense for where to connect the negative side of the charger, but where are you putting the positive side of the charger to charge the Aux battery by itself?

If you use the positive side of the main battery, you will charge the Aux battery with the PCR in the circuit. If you put the positive of the charger on the N1 terminal, it will charge the Aux battery directly. Do we know which is preferred?

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