Your battery voltage - truck off and at rest

[t-bot]

Just checked -
'22 JTRD - Last driven ~19 hours ago - 12.51 v (temp ~55f)
~3100 miles/in service since Jan 6th

I haven't had any problems with ESS, other than it actually working , but that's been debated ad nauseum.

Good luck to you.

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[ShadowsPapa]

Just checked -
'22 JTRD - Last driven ~19 hours ago - 12.51 v (temp ~55f)
~3100 miles/in service since Jan 6th

I haven't had any problems with ESS, other than it actually working , but that's been debated ad nauseum.

Good luck to you.

LOL - I hear ya.

Thanks. With the temperature being lower, without looking, I'd have to expect a slightly lower top voltage. That 12.51 is still a fair amount higher than mine was. I just checked my wife's Grand Cherokee - she made a comment "how come it's not shutting off when I sit at stop lights" and I asked her to scroll to page 7 - and it showed "not ready" but no battery charging. Today I checked the voltage after sitting about 14 hours and it was 12.35 - good grief, a 30 minute drive to town, then a 30 minute drive back, 2/3 interstate, and the batteries are still not topped off? Yes, it's 35 degrees out now but still, I expected at least 12.5 or so.
She had both batteries totally fail to the point of it just plain not cranking over at all on her 2018 WK2 and this 2021 may end up with the same issues.

 

[u-joint]

Mine has been parked since mid-afternoon Sunday. I'll go measure it tomorrow and give you a number.

I just went to measure mine, but I guess my multi-meter isn't working. It just kept reading 0 volts, which clearly wasn't correct.

 

[Kevin_D]

Battery voltage - truck off-
How many hours has it been sitting, engine off -
Does ESS function correctly-
Has the dealership worked on the truck to resolve ESS, if so did they replace batteries or reset the IBS-

A) 12.66VDC, 60ºF
B) ~22 hours
C) Yes, always has. Been in service since 09/20
D) No.

Keep in mind that all those tables are showing Open Circuit Voltage. To truly measure the battery, you need to completely disconnect it and let it sit for a couple hours, as the JT is always drawing current, albeit very small amounts when it's asleep.

Kevin

 

[ShadowsPapa]

Keep in mind that all those tables are showing Open Circuit Voltage. To truly measure the battery, you need to completely disconnect it and let it sit for a couple hours, as the JT is always drawing current, albeit very small amounts when it's asleep.

Except the last chart I posted. It is showing SoC with a .1C discharge rate and still showing that mine isn't even 80% (although it's not got that great a discharge on it or it would be dead in a few short days)
The discharge according to another member who had the dealership troubleshoot his dead battery said .01 amps discharge as I recall...... the number was in the hundredths of an amp, not tenths. My chart is showing a lot more discharge which according to him would be way too much discharge for a Jeep.
You don't pull hundredths of an amp and drop battery voltage from 12.8 to 12.19.
I can turn the knob on my test stand's carbon pile and not drop a normally battery that much and I'd be pulling full amps, not tenths or hundredths of an amp.

 

[GRDIESEL]

12.38VDC - 45 degrees F
60 minutes
Sometimes
Yes
Truck was at dealership last week for ESS. Dealer said batteries were heavily discharged and they charged them back up.

 

[ShadowsPapa]

Dealer said batteries were heavily discharged and they charged them back up.

And that's what gets me in this - most are showing voltages that indicate batteries that are only sitting at 70% or so charge. Driving with the alternator regulated at 14.7 volts should charge almost any AGM battery. It takes almost nothing to start these so what's up with the batteries not being charged 100% or at least 80-90%
With a 240 amp alternator, you should not be drawing out of the batteries once it's started.

 

[4S50]

12.3 V
last driven 12 hours ago and has been sitting in 60 degree garage.
I have no idea if the ESS works, the Tazer keeps it turned off for me.

 

[Maximus Gladius]

So Papa, I was hoping I could raise your eyebrows just a bit and throw in some data going live right now as I type this… I’m also pretty sure no one has posted this info on our batteries before so please excuse the slight deviation from your thread post.

You recall with my dead Gladiator case I’m legally going after my dealership and FCA for,…the dealership gave my truck back, electrically dead as well as the imploded transmission and what nots, then via email, recommended I fix it. Well, I pulled the two batteries out and so far, have only put the big battery on a trickle charger set to 10A.

When I hooked up the battery, it was reading 0 on everything. The charger has been hooked up for 7 hours so far and reading just slightly north of 6V. I took the battery temperature along the cells and as you can see, the outside cells don’t read any temp while the ones into the middle read some temps, but sporadic. I’ve only been hooked up to the battery all day so far.

Did I stumble onto something here or is this nothing?

 

[Maximus Gladius]

I went out to see all the temps were starting to level off across the inner cells to 35.4c, the outer cells still not reading a temp. I clicked over the charger to 2A and will let it go all night. When I switched it down, the 6.5V reading dropped to 4.5V. My gut says the battery is pooched, something more the dealership didn’t give a shit about when they had my truck.

 

[Maximus Gladius]

Went out this morning to check on the 2A all night charging. The start battery dropped from 4.5V to 4V. I stuck the leads on the aux battery and it read 1.7V. I put the leads back on the main battery and switched the charger to 10A and let’s see what it looks like at noon. I think it’s toast and I don’t even want a replacement. I’m looking at duel battery upgrade. Do I want to constantly worry if my truck will start when I’m out traveling around?

 

[Beemer533]

I went out to see all the temps were starting to level off across the inner cells to 35.4c, the outer cells still not reading a temp. I clicked over the charger to 2A and will let it go all night. When I switched it down, the 6.5V reading dropped to 4.5V. My gut says the battery is pooched, something more the dealership didn’t give a shit about when they had my truck.

Yeah, with voltages that low that battery is done.

When my main battery died I measured around 5v disconnected from the truck. The jump pack wouldn't even recognize that it was connected.

I had to get a manual charger and force it around 17 volts for a bit to get it to start charging. I charged it for quite a few hours at the recommended 14.2 ish volts and I was able to start it and drive it to the dealer without any trouble.

But regardless, the dealer said it was completely dead the next morning and the battery was bad..

 

[DobaMark]

I don't have a meter for actual readings. It's still packed away from the last move.
Truck would show 12.0 to 12.2 on the dash after siting for a day. Two days ago I used my battery charger to trickle charge to full. Drove the truck long enough to get it up to temperature and still got the battery charging message.
After sitting 2 days, voltage now reads 12.2. Attached the charger again and it read 75% charge which matches what SP's charts say.
I'm sure the dash reading isn't as accurate as a meter, but it's all I have available. Stop/start hasn't worke din a couple of months. I'm in Georgia where winter really isn't that cold.

 

[Maximus Gladius]

Went out this morning to check on the 2A all night charging. The start battery dropped from 4.5V to 4V. I stuck the leads on the accs battery and it read 1.7V. I put the leads back on the main battery and switched the charger to 10A and let’s see what it looks like at noon. I think it’s toast and I don’t even want a replacement. I’m looking at duel battery upgrade. Do I want to constantly worry if my truck will start when I’m out traveling around?

Just checked the charging on the main battery. Earlier, switching up the power to 10A, the battery went from 4V to 5 then has now dropped to 4V again. It’s done.

I’ve put the leads over to the accs battery and set the charge to 2A, battery reads 0V. When I switch to 10A, it reads 1.7V. I left it on 2A charge and will leave it for a while.

 

[abe57]

Drove mine yesterday to the smoke shop about 20 min. drive to and back just measured mine in the garage at 62 deg. and she measured at 12.47 V. 2021 Mojave 3.6 Auto 7800 miles.

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