On this episode of "Batteries gone bad"

[MoxiesDad]

Sounds like your main battery wasn't fully charged when installed.

Sponsored

 

[Escape.idiocracy]

Sounds like your main battery wasn't fully charged when installed.

NOCO GENIUS5 Said it was? volt meter showed 13.1 and change before install…

 

[Mr._Bill]

This thread has been really helpful.
factory main battery failed the autozone test- 2.5 years old. Figured we just didn’t quite get the full 3 years most others get. Replaced both main and auxiliary. (Stuck both on Chargers before installing to ensure we’re full) duralast platinum agms- September and October manufacturers production date.


Few days later voltage in the cab is reading 12.2-12.3 @ start up. Had a long 150 mile drive for the weekend running voltage fluctuated from 13.6-14.4 (normal- I think). Next day again low 12’s

Pulled both batteries put them on a charger… auxiliary battery was basically full/topped off. Main battery read less than 80%… will leave until full, then leave off the charger for a few hours and will check voltage settled amount.

checked the fuse array- all passed continuity, pulled ALL fuses… … micro fuses… checked the canbus plugs under/behind the glove box. So far not finding any “ah-ha’s” -

Almost wondering if we picked up a bad main battery?? As it seems we have the opposite problem to most, in that the auxiliary is charging fine in the car, but not the main…?

Anyone have any other troubleshooting ideas or thoughts that they would like to share?

Which head unit do you have?
Is it driven at least thirty minutes a day?

Take the main battery back to where it was purchased and have it tested. Find out if it is a problem before spending a lot of time troubleshooting.

These trucks have a high parasitic draw, especially with the 8.4 head unit. They have to be driven enough to keep the batteries charged, or kept on a battery maintainer to get the maximum life out of the batteries.

I understand your concern, but not yet sure that there's an actual problem.

 

[ShadowsPapa]

Understood, batteries should last 7 to 10 years. But with this type of paring that will never happen. Just saying the baby battery is always going take the brunt of abuse in this type of install. Thinking otherwise won't change the way its being abused.

No, modern batteries don't last that long. Refer back to the times I've told of the conversation I had with guys in a NAPA store talking about batteries - comments "I can't get a battery to last over 4 years.........." and so on, and they were not Jeep owners.
That small aux battery isn't taking abuse. It's just a bad Jeep battery, and it's small.

Jeep did NOT invent this system and is not the only automaker to use it. It's been used by BMW, Chevrolet and others over the years.

Part of the issue is how little vehicles are driven these days - I mean people think 7 miles is a long way "but I have a 7 mile commute" - that's a commute? I used to walk far more than that just because. And that's abusive to the whole vehicle, not just the battery.
You can't start a vehicle and drive it 10 minutes there and 10 minutes back and believe the battery is fully charged. It isn't. Not even close.

Always when replacing one or both batteries - and this is ALWAYS:
Fully charge the battery with a good charger.
Leave the IBS disconnected from the ground and battery for 10-20 minutes while replacing battery/batteries.
Connect everything back up when the battery/batteries are installed.
this ensures that the batteries are topped off and the IBS relearns with fresh batteries that are fully charged. If the battery, especially the main, isn't fully charged when installed, you'll have issues - the IBS will be learning with a bad set of data.

Few days later voltage in the cab is reading 12.2-12.3 @ start up. Had a long 150 mile drive for the weekend running voltage fluctuated from 13.6-14.4 (normal- I think). Next day again low 12’s

Running voltage sounds right............ it may be higher or lower depending on the batteries and their state of charge, engine torque output, ambient temperature and more.
But 12.2 is very low. Even sitting for 3 days it shouldn't drop a fully charged good battery that far. 12.4 perhaps.
Mine has been sitting for about 4 days now since we have a loaner for my wife's Jeep being in the shop and we've been putting the miles on the loaner (shhhhhh) and letting my poor JT sit for a while. I need to check what the voltage is on it tomorrow.
Ironically, I've found I need to run mine through a couple of full charge cycles for things to settle down.


I've actually used my BatteryMinder 1500 mA "battery minder" to resurrect older batteries, breathe new life into a 7 year old battery in my Javelin (and that car sits a lot) and even old lawn tractor batteries. Something about how it charged and desulfates seems to add life back to batteries I was about to give up on.

 

[Escape.idiocracy]

Which head unit do you have? The larger nav unit.
Is it driven at least thirty minutes a day? Yes most days, and this battery is only a week old.

Take the main battery back to where it was purchased and have it tested. Find out if it is a problem before spending a lot of time troubleshooting.
Will do- it’s 27* outside, so I’m not looking to troubleshoot much until this afternoon.. I left the battery off the charger and on the bench to see what the settled voltage is- will check in an hour or so…

These trucks have a high parasitic draw, especially with the 8.4 head unit. They have to be driven enough to keep the batteries charged, or kept on a battery maintainer to get the maximum life out of the batteries.
I guess my concern/surprise was, having charged them both when new- then taking a longer 3 hour one way drive, and after parking finding the lower voltage was eye opening… something is a miss.

I understand your concern, but not yet sure that there's an actual problem.
Hopefully all is well- timing wise, it’s weird, no electrical changes….

 

[Escape.idiocracy]

Which head unit do you have?
Is it driven at least thirty minutes a day?

Take the main battery back to where it was purchased and have it tested. Find out if it is a problem before spending a lot of time troubleshooting.

These trucks have a high parasitic draw, especially with the 8.4 head unit. They have to be driven enough to keep the batteries charged, or kept on a battery maintainer to get the maximum life out of the batteries.

I understand your concern, but not yet sure that there's an actual problem.

Any chance you have the # of amps on the “normal” parasitic draw? When I put it back together today I want to see where I’m at.

12.78V after sitting 12 hours on the bench. - Going to play with it more today, but if I can’t get anything to shake free I’ll run it for a draw down test and exchange it

connected in the Jeep- haven’t opened any doors. (20 min after taking bench reading)

Reading after shutdown

reconnect- vehicle off voltage read 12.2 -started and jumped to 12.5.

Idling now and voltage is slowly rising…. 12.7

Just going to send it- if the battery fails it’s under warranty, and I’ll figure out the root then…. lol. This system seems more complicated than it’s worth…

 

[ShadowsPapa]

This is where I seriously wish more Jeep Gladiator owners were a bit closer.........

I didn't see or missed it maybe, but do you still have the aux battery in place? If so, it could be pulling the main battery down that badly when you hook things back up.
This may be a case of both having failed.

If you have the aux battery in place, try charging just that one - take the ground cables off the main battery, take the two ground cables apart from each other.
One goes to the chassis ground, the other ground cable goes to the aux battery negative.
Leaving the positive connected on the main battery, but having the negative cables both off the top of the IBS, connect charger to the main battery positive cable and the charger negative to the black cable going down to the aux battery.

For a 2020 Gladiator model year, the cable marked 2020 goes to the aux battery negative and is used to charge it
For a 2021 and later JT, the cable marked 2021+ is the negative for the aux battery.
The arrow points to the IBS - take the right nut off to remove the cable assembly from the top of the IBS, and take the nut off the taller stud to take the two cables apart from each other. Don't let either touch the main battery negative through any of this.

The below pic is for charging a 2020 Gladiator. Note the positive charger clamp is on the main battery positive since it's connected electrically to the aux battery, and the negative charger clamp is connected to the ground cable that goes down to the aux battery negative. For 2021 and later, this is changed around so see pic above to note which cable is which as far as aux battery ground cable.
In this case I could leave the main battery ground to chassis cable connected as it's not interfering in any way but for 2021 and later, that cable i left on the IBS of my 2020 is the one that you use to charge the aux battery so must be disconnected from the main battery in order to charge only the aux battery.

I have found far batter luck taking the cables apart and charging each battery rather than both together because they vary in capacity and sometimes even age or condition. If they were both new - not as big a deal and both can be charged, it's just "neater" to do each on their own and that way differences in age, condition and so on are accounted for by the charger.

Sponsored