Voltage reading 12.5 volts after changing main battery

[Towzone100]

Hope everyone is doing well.

So, I have a strange situation. I received the “auxiliary switches temporarily unavailable battery charging” message on my 2021 Gladiator ecodiesel. The last time this happened, I replaced both batters. This time, I figured I would remove the Aux from the system by pulling fuse F42 and removing its negative cable. All worked fine after doing so. The issue came after replacing the main battery. My voltage gauge drops to 12.6 volts. It was bouncing around from 14.2 to 13.9, but now it is sitting at 12.6 volts. I know the IBS needs to go through the relearn process, but is it normal for the voltage gauge to drop that low? I can't remember if this happened the last time I replaced the batteries.

Sponsored

 

[Mr._Bill]

If it drops to 12.6 and stays there while the truck is running, that usually indicates that the battery is fully charged. When it goes above 13, it is charging the battery. When it goes above 14, the battery is really low.

 

[ShadowsPapa]

Hope everyone is doing well.

So, I have a strange situation. I received the “auxiliary switches temporarily unavailable battery charging” message on my 2021 Gladiator ecodiesel. The last time this happened, I replaced both batters. This time, I figured I would remove the Aux from the system by pulling fuse F42 and removing its negative cable. All worked fine after doing so. The issue came after replacing the main battery. My voltage gauge drops to 12.6 volts. It was bouncing around from 14.2 to 13.9, but now it is sitting at 12.6 volts. I know the IBS needs to go through the relearn process, but is it normal for the voltage gauge to drop that low? I can't remember if this happened the last time I replaced the batteries.

Did you fully charge the battery before installing it?
Did you remove and leave the IBS disconnected for at least 15 to 20 seconds or so, then put it back on a fully charged battery?
Bouncing 14.2-13.9 then a sudden drop to 12.6 bothers me.
That's less than a fully charged battery, meaning it's not even maintaining that battery.

If it drops to 12.6 and stays there while the truck is running, that usually indicates that the battery is fully charged. When it goes above 13, it is charging the battery. When it goes above 14, the battery is really low.

My batteries were both fully charged yesterday - ended up with 12.7 volts after surface charge finally drained off.
System read 14.7 volts all the way across town to West Des Moines and back.
I rarely see 12.6 volts on a fully charged battery unless that battery is hot on a hot day and I've been driving for a couple of hours.
It will almost always keep 13.x volts as a maintenance level while driving.
Can't say yet why mine was running in the 14s today other than it was in the 50s and lower temps mean higher voltages.
The only time I ever see voltages in the low 13s or lower is when it's hot and I've been driving it a lot.

 

[Towzone100]

If it drops to 12.6 and stays there while the truck is running, that usually indicates that the battery is fully charged. When it goes above 13, it is charging the battery. When it goes above 14, the battery is really low.

Thanks Mr. Bill. I figured as much but usually it sits around 12.9 or so. I did upgrade to a H7 from an H6.

 

[Towzone100]

Did you fully charge the battery before installing it?
Did you remove and leave the IBS disconnected for at least 15 to 20 seconds or so, then put it back on a fully charged battery?
Bouncing 14.2-13.9 then a sudden drop to 12.6 bothers me.
That's less than a fully charged battery, meaning it's not even maintaining that battery.



My batteries were both fully charged yesterday - ended up with 12.7 volts after surface charge finally drained off.
System read 14.7 volts all the way across town to West Des Moines and back.
I rarely see 12.6 volts on a fully charged battery unless that battery is hot on a hot day and I've been driving for a couple of hours.
It will almost always keep 13.x volts as a maintenance level while driving.
Can't say yet why mine was running in the 14s today other than it was in the 50s and lower temps mean higher voltages.
The only time I ever see voltages in the low 13s or lower is when it's hot and I've been driving it a lot.

I removed the old battery from the truck and let the truck sit for 15 minutes without any batteries before connecting up the new Optima battery yellow top H7. I did not isolate the IBS from the ground cable or unplug its cable but it was not attached to a battery.

The odd thing is after driving it for a while it was bouncing all over the place, finally stabilizing at 14V. After a little while it dropped to 12.6V but it is not going blow that.

I did through my Foxwell on it and it is retaining the old battery information. Therefore it has not recognized the new battery.

 

[Mr._Bill]

I removed the old battery from the truck and let the truck sit for 15 minutes without any batteries before connecting up the new Optima battery yellow top H7. I did not isolate the IBS from the ground cable or unplug its cable but it was not attached to a battery.

The odd thing is after driving it for a while it was bouncing all over the place, finally stabilizing at 14V. After a little while it dropped to 12.6V but it is not going blow that.

I did through my Foxwell on it and it is retaining the old battery information. Therefore it has not recognized the new battery.

12.6 is a little low, usually it is 12.7 or 12.8 while running with a fully charged battery. It could be the IBS didn't reset, it may need to be completely disconnected. Hopefully, one of the high current fuses didn't pop. It can happen if there's an accidental short when swapping the batteries.

 

[Towzone100]

Yeah I did have an accidental short. I thought the same thing but I didn't have any other lights come on and it was charging at first. May have to pull the array and meter the fuses.

 

[Towzone100]

12.6 is a little low, usually it is 12.7 or 12.8 while running with a fully charged battery. It could be the IBS didn't reset, it may need to be completely disconnected. Hopefully, one of the high current fuses didn't pop. It can happen if there's an accidental short when swapping the batteries.

So a quick update. I pulled the fuse array and checked them and all were good. I pulled the negative cable and let the truck sit for 45 minutes, hoping the IBS would reset. Reinstalled the fuse array and negative battery cable. The volts are reading differently this time. They started off at 12.8 and moved up as high as 14.7 and back down to 13.1 volts in a 20-minute drive. If I had to guess it must be the IBS relearning and maybe the fact I upgraded from a factory H6 to an Optimal yellow top H7. The funny thing is I checked the battery this morning before starting it and it was reading 12.8 volts. So at least driving it yesterday did not strain the battery.

BTW - if anyone has an H6 installed and wants to upgrade to an H7. All that you have to do is remove a tab in the battery tray.

Thanks for the help guys. I will come back and update you after the IBS is relearned. The funny thing is my daughter has a Mini Cooper. All I needed to do was reprogram the ECM to let it know the battery specs. I wish Jeeps were the same way.

 

[wolfdog]

Jeep engineers gave us the Aux battery for ESS what do you expect? My Cherokee TH had one large battery and the ESS worked better than mt JLU and my JT!!!

Go Jeep!!!

 

[Towzone100]

Jeep engineers gave us the Aux battery for ESS what do you expect? My Cherokee TH had one large battery and the ESS worked better than mt JLU and my JT!!!

Go Jeep!!!

So true. The funny thing is this has the TOW package and the factory installed a H6 battery. What?
The new H7 is a beast.

 

[ShadowsPapa]

Jeep engineers gave us the Aux battery for ESS what do you expect? My Cherokee TH had one large battery and the ESS worked better than mt JLU and my JT!!!

Go Jeep!!!

Jeep engineers didn't invent this system. They adopted it. Other companies, including BMW and Chevrolet, have used this same type of system.

So true. The funny thing is this has the TOW package and the factory installed a H6 battery. What?
The new H7 is a beast.

Tow package has nothing to do with the battery size. Aux switches make the difference. If you have the aux switches, you got the larger battery.

Frankly, I'd totally remove, unplug, disconnect, whatever, the IBS. I mean lay it out on a bench not connected to anything.
I know the docs say all that's needed is to remove it from the battery and remove the ground cable (in cases where an aux battery still exists) but I always try to err on the side of "there's no way in @#$% it didn't reset" - paranoia?

It doesn't take long to relearn. It can do that in a couple of start cycles in a single afternoon if it sits a while between starts. I've got the info on that somewhere from FCA.

I did through my Foxwell on it and it is retaining the old battery information. Therefore it has not recognized the new battery.

capacity is determined by applying a known load over a period of time and seeing how long it takes to drop to a specific voltage. Not sure these actually learn capacity or are programmed for that -
Here's my 2020 numbers -

IBS3 Battery Capacity (0-252 Ah): 254.000 Ah
IBS3 Parameterized Type of Battery Mode: Signal Not Avaiable
IBS3 Maximum OCV Voltage (13-13.33 V): 13.000 V

Did you see the first line? 0-252 and what's it say? 254!

Battery:
___________________
IBS3 Battery Equivalent Capacity (9000-405000): 405000.000 %
IBS Quiescence Current Limit (-250-0 mA): -250.000 mA
IBS Minimum Voltage Limit (0-25.4 V): 10.000 V
IBS3 Charge Current Limit (0-2500 mA): 2500.000 mA
IBS3 Battery Parameterization Kind- Battery Mode: Use Battery Type
IBS3 Vehicle Battery Type (0-63): 22.000
IBS3 Minimum Charge Limit (0-100%): 35.000 %

 

[wolfdog]

So BMW and Chevy adopted it, that means it's good??? !! As mantioned my 2015 Cherokee had ESS and it worked like a charn, no crap aux battery just a large HD battery thar lasted 7 years!!

Just got a qoute for replacing both batteries in out 2018 Wrangler $600 bucks! Looks like the fender or fender liner coming off...great engineering1 maybe with BMW and Chevy ya just hafta remove the AC unit!! What a Joke...not so much!

Go Jeep!!!

 

[sharpsicle]

So BMW and Chevy adopted it, that means it's good??? !! As mantioned my 2015 Cherokee had ESS and it worked like a charn, no crap aux battery just a large HD battery thar lasted 7 years!!

Just got a qoute for replacing both batteries in out 2018 Wrangler $600 bucks! Looks like the fender or fender liner coming off...great engineering1 maybe with BMW and Chevy ya just hafta remove the AC unit!! What a Joke...not so much!

Go Jeep!!!

This has been beaten to death. The system's design isn't the root cause of the problems, its the quality of the batteries that is the issue.

 

[Towzone100]

This has been beaten to death. The system's design isn't the root cause of the problems, its the quality of the batteries that is the issue.

I agree 100%. It is the quality of the batteries.

 

[Towzone100]

Jeep engineers didn't invent this system. They adopted it. Other companies, including BMW and Chevrolet, have used this same type of system.



Tow package has nothing to do with the battery size. Aux switches make the difference. If you have the aux switches, you got the larger battery.

Frankly, I'd totally remove, unplug, disconnect, whatever, the IBS. I mean lay it out on a bench not connected to anything.
I know the docs say all that's needed is to remove it from the battery and remove the ground cable (in cases where an aux battery still exists) but I always try to err on the side of "there's no way in @#$% it didn't reset" - paranoia?

It doesn't take long to relearn. It can do that in a couple of start cycles in a single afternoon if it sits a while between starts. I've got the info on that somewhere from FCA.


capacity is determined by applying a known load over a period of time and seeing how long it takes to drop to a specific voltage. Not sure these actually learn capacity or are programmed for that -
Here's my 2020 numbers -

IBS3 Battery Capacity (0-252 Ah): 254.000 Ah
IBS3 Parameterized Type of Battery Mode: Signal Not Avaiable
IBS3 Maximum OCV Voltage (13-13.33 V): 13.000 V

Did you see the first line? 0-252 and what's it say? 254!

Battery:
___________________
IBS3 Battery Equivalent Capacity (9000-405000): 405000.000 %
IBS Quiescence Current Limit (-250-0 mA): -250.000 mA
IBS Minimum Voltage Limit (0-25.4 V): 10.000 V




IBS3 Charge Current Limit (0-2500 mA): 2500.000 mA
IBS3 Battery Parameterization Kind- Battery Mode: Use Battery Type
IBS3 Vehicle Battery Type (0-63): 22.000
IBS3 Minimum Charge Limit (0-100%): 35.000 %

My understanding is the larger battery is needed with the Tow package in order to handle the load of the trailer lights. I addition I do have the AUX switch's. That's why I upgrade to a H7.

As for the IBS relearn process, I plugged my Foxwell in and the truck still has the old factory battery data stored in it. That tells me it's still learning.

This is from Jeep based on the relearning process.

This relearning process requires 5 normal, operator initiated starts with at least eight hours off time between each start. Usually, the process takes a few days of vehicle operation to complete.

As for removing the IBS. I will once the truck is out of warranty.

Sponsored