Your battery voltage - truck off and at rest

[jac04]

I could just as easily bolt to the battery terminal clamp bolt.........

Thinking more about this ... if you put your winch neg. cable directly onto the neg. battery post, you will provide a ground that does not go through the IBS. I'm not sure you want to do that as a permanent installation.

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[Beemer533]

I just got home from a work trip so my truck has been sitting since the last measurement I took, which I think was 12.29 volts . Just For kicks I measured it just now at 12.18 volts.

As I drive now it is charging at 14.9 Volts

 

[ShadowsPapa]

Thinking more about this ... if you put your winch neg. cable directly onto the neg. battery post, you will provide a ground that does not go through the IBS. I'm not sure you want to do that as a permanent installation.

No, I plan on putting it back where it was. It worked fine and it can't possibly be the cause of any draw or issues with charging, battery voltage, etc. - it's basically just a dead cable hanging there connected with nothing on the other end until I turn that switch in the positive cable and let the electronics have power - even then, unless you flip the switch for wireless remote, it has zero draw because it's expecting a physical switch connection via the remote cable.
I can't see how anyone believes a winch is a parasitic draw on anything when it's turned off, and especially when that big red switch next to the battery is in the OFF position. I guess they aren't familiar with the old physical electric switch.

 

[bakobobby]

I picked up my truck this morning. They had charged my "severely discharged" battery assume they meant the aux. From the get go my ESS was not working. They had the info screen up for ESS and it was flashing various reasons including engine not warm enough. after 15-20 minutes of driving it did kick on but just once right before I got home. I have to say this system seems rather finicky in compared to my Chevys that just seemed to always work. I find it kinda useless that it won't even kick on for that long of time driving around town because I rarely drive longer than 15-20 minutes in one sitting unless doing highway miles.

 

[ShadowsPapa]

I just got home from a work trip so my truck has been sitting since the last measurement I took, which I think was 12.29 volts . Just For kicks I measured it just now at 12.18 volts.

As I drive now it is charging at 14.9 Volts

Actually that's the voltage from the alternator - from what I've been reading lately, that's not actually indicating what's going to the battery. It can read 14.x and still not actually charge. It's a weird system.
When I got home after they supposedly charged the batteries for 38 minutes before they did the load test, (it's a 30 minute drive home and I made a 10 minute drive to the bank as a side trip) mine read 12.5 volts. STILL not fully charged but the ESS worked. Today I measured and it's 12.3 again.
They charge the batteries, instantly do a load test and say they are ok, but then they go down in a few hours. I've had batteries that passed a load test right after charging but the next day wouldn't start a car (internal issues in the batteries) so IMO, a charge it, load test it, it's fine isn't a great test. They didn't even fully charge the batteries.

 

[Erievon]

My 20 Overland and Wifes 21 JL are doing the same thing. Both are reading around 12.2 on the main battery after sitting overnight. No matter how much I drive the JT, it says "ESS Not Ready, Battery Charging". Here's the kicker, on the wife's 21 JL, the message just says ESS Not ready" doesn't say anything about the battery charging.

So I broke out the battery tender, it took 9 hours to go into "float" mode charging at 2amps. At that point I read 12.6 at the main battery. Then drove it, ess worked fine for 2 days, And the dash volt meter actually floated between 13.2 to 13.7, occasionally even seeing flashes of 12.7 that day and the next, both drives were about 20 minutes. By day three, it's back to 14.5 on the dash, ESS Not ready, and reading 12.2-12.3 after sitting a few hours. 14.5 for 20 minutes should be enough when it started full...

 

[misplacetexan]

That aux battery voltage is low, are you sure the blown fuse was repaired so the aux battery can get charged from the alternator?

Yes, if the aux battery isn’t charging, the truck will shut down. Don’t ask how I know. My aux battery was down to 10 volts while I was troubleshooting. My JT‘s digital display (speedometer) was showing low voltage, before the truck turned off in my driveway. That’s also how I realize that voltage displays the auxiliary battery voltage/charging on pin 3.

 

[Erievon]

I'm traveling on business next week, Fly out Monday, Return Friday evening. I was just going to park in long term parking but now this has me thinking...I think I'll uber to and from the airport. I'd rather have it dead in my garage then in the airport parking lot if a week is all it takes to kill it. I shouldn't have to think this way on a vehicle with only 7k miles.

 

[Beemer533]

Actually that's the voltage from the alternator - from what I've been reading lately, that's not actually indicating what's going to the battery. It can read 14.x and still not actually charge. It's a weird system.
When I got home after they supposedly charged the batteries for 38 minutes before they did the load test, (it's a 30 minute drive home and I made a 10 minute drive to the bank as a side trip) mine read 12.5 volts. STILL not fully charged but the ESS worked. Today I measured and it's 12.3 again.
They charge the batteries, instantly do a load test and say they are ok, but then they go down in a few hours. I've had batteries that passed a load test right after charging but the next day wouldn't start a car (internal issues in the batteries) so IMO, a charge it, load test it, it's fine isn't a great test. They didn't even fully charge the batteries.

Interesting. So it's only charging above 15?

It seems strange because the battery says to not charge it over 14.4, but maybe the dash readout is not really the best way to verify that...

Was that the dealer you brought it to? When I brought mine in they told me the only way to get it warrentied was to have the computer test it and issue the work order and that the test took nearly 6 hours. If they didn't run it though the computer and just replaced it (even if obviously bad), FCA would not pay them.

Maybe different if you are not under warranty?

 

[Jaxmax]

2021 Mojave, sat for seven days until last night started it up and moved front two feet in garage and shutoff, after twenty seconds, just checked tonight 12 volts sitting 15 volts running. I drive a lot with my work truck and the Glady sits in garage sometimes for two weeks before I get time to drive it . never had any ESS issues or starting issues. Have been wiring bed up for water pump, refrigerator, air compressor and RSI cap lighting both white and red night time lighting. If I do much sleeping in bed I'll probably get a dual battery setup......Jack

 

[Gatorized]

thought it would be beneficial to have a diagram for all to work with. Pin 1 goes direct to the aux battery, pin 3 goes through the PCM.

 

[ShadowsPapa]

thought it would be beneficial to have a diagram for all to work with. Pin 1 goes direct to the aux battery, pin 3 goes through the PCM.

What is that supposed to be of? That's not the IBS.


The IBS is on the negative terminal of the main battery - which you have marked current sensor.

This is the IBS - there is a pair of wires that goes to the bus.

This shows the IBS on the negative battery terminal with the red and yellow wires indicating the wires from the IBS to the ECU.

 

[Gatorized]

I’m guessing Current sensor and IBS must be the same thing.

 

[ShadowsPapa]

I’m guessing Current sensor and IBS must be the same thing.

Yeah, this is from some info I have ->

The Intelligent Battery Sensor (IBS) contains a low value resistor, or shunt. The shunt creates voltage drop, which is read by an internal microcontroller to determine the current flow in and out of the battery.

and

At the heart of an IBS is a shunt, which is specifically designed for sensing battery currents. The precision internal electronics of the IBS should be robust enough to handle the under-hood environment of modern vehicles and maintain accuracy when sensing the voltage drop across the shunt.

 

[Gren71]

Reading through all of this and it’s become clear i know less about my truck than I thought I did.

My own ignorance reminded me of a fantastic counseling bullet point i read years ago. “Soldier has found rock bottom and shows signs of starting to dig”

while pulling my camper home today to de winterize it i had my curt echo up. When the truck shut off the echo app would flash “low battery” ive never seen that before. With the truck off at the stop light the battery read 12.2-12.4 on the dash. It popped back up to 14.5-14.7 quickly once the truck started back up.

am I starting to see a issue or am I connecting dots that aren’t there?

the jt is nearly 3 years old and has 63,000 miles on it. So im sure im probably due for a new battery soon anyway.

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