maximum voltage on dash readout

[WranglerMan]

I just replaced the Main and Aux batteries with Odyssey batteries. While driving I read 14.7V even after driving 30 miles. Outside temps 20s to 40s.

This does not seem normal.

If you just replaced both batteries and had the IBS disconnected while swapping them out it takes a few cycles for the IBS to relearn, my Jeep has has been parked for almost a week in temps close to zero and when I went out yesterday the EVIC indicated 14.7 and about an hour later was 14.3 and by the time I got home after it had ran a few hours it was 12.7.

Did you fully charge the batteries before installing them? I would suggest you get like a NOCO 10 trickle charger and fully charge both also I would suggest you get a battery tester similar to this one https://a.co/d/2ghpHfV its a pretty cheap investment that can test your batteries and also do several other tests.

If your 30 mile drive involved a few stops each time you start your Jeep it can pull 7-10 % power from the batteries, don't solely rely on the EVIC display to judge the condition of the batteries.

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[melendez69]

Voltage readings of 15v+ on AGM batteries have been a topic on the 6Speedonline forum for quite some time. I'm on a pair of 2-month old Optimas & started around 12.8 - 14.2; when the temps dropped from the 40s to the 20s/teens here, I started seeing as high as 14.6.

My driving habits range from short trips to 66 miles round-trip a couple times a week.

This from a few members of the 6Speedonline forum (I've also seen this here somewhere).

 

[WranglerMan]

As I stated in my earlier post my Jeep has been parked for several days and its been cold here in Indiana and my trip out yesterday resulted in my EVIC starting out at 14.7 and after a few hours out was down to 12.7.

So just as a test I got out my Motopower tester and did some quick tests on my two Full River 750-25’s in my dual Genesis setup and also tested the charging system.

After I did my tests I started the Jeep and my EVIC displayed 14.7 so I would be curious what the Jeep Engineers were thinking when they designed this complicated charging design.

 

[Obscurity]

From a Stellantis document regarding RAM alternators and charging:

"The eTorque engines use a DC to DC convertor to charge the 12V system.
...
Voltage set point 13.3V-14.7V depending on temperature."

Obviously, that voltage range is not necessarily directly and precisely applicable to JLs - especially those with traditional alternators. But, the parameters are perhaps broadly indicative of target voltage bounds.

Thanks What was the document and are you aware of an equivalent JL document?

 

[Mguy]

Voltage readings of 15v+ on AGM batteries have been a topic on the 6Speedonline forum for quite some time. I'm on a pair of 2-month old Optimas & started around 12.8 - 14.2; when the temps dropped from the 40s to the 20s/teens here, I started seeing as high as 14.6.

My driving habits range from short trips to 66 miles round-trip a couple times a week.

This from a few members of the 6Speedonline forum (I've also seen this here somewhere).

Voltage charge/temperature charts address ambient conditions. Unfortunately from a battery's point of view, vehicle charging takes place in a heated engine compartment. Since charging for most vehicle operation mostly takes place when engines are warmed up, cold weather doesn't have that much effect on desirable charging voltages.

 

[THAW]

Thanks What was the document and are you aware of an equivalent JL document?

The document is titled "RAM Ligtht Duty DT Alternator and Charging information 2022", and was produced by the "STELLANTIS North America Commercial Vehicle Team." I found it on a RAM forum while google searching a different topic.

I don't know of anything equivalent for the JL.

 

[Doug G]

If you just replaced both batteries and had the IBS disconnected while swapping them out it takes a few cycles for the IBS to relearn, my Jeep has has been parked for almost a week in temps close to zero and when I went out yesterday the EVIC indicated 14.7 and about an hour later was 14.3 and by the time I got home after it had ran a few hours it was 12.7.

Did you fully charge the batteries before installing them? I would suggest you get like a NOCO 10 trickle charger and fully charge both also I would suggest you get a battery tester similar to this one https://a.co/d/2ghpHfV its a pretty cheap investment that can test your batteries and also do several other tests.

If your 30 mile drive involved a few stops each time you start your Jeep it can pull 7-10 % power from the batteries, don't solely rely on the EVIC display to judge the condition of the batteries.

I fully charged the batteries before install. Cycles was it. After a week of driving, the voltage went back to normal, 12.8V by the end of the drive.

Thanks for the link to a battery tester.

 

[Jebiruph]

I've spent a lot of time monitoring my voltage over the past 7 years. A short commute has led to a lot of 14.7 V charging, but since the last firmware update for the manual transmission recall, I'm seeing a lot of 15.1 V charging.

I should have explained my point better. It's not the battery that determines the charging voltage, it's the PCM that controls the alternator that determines the charging voltage. It appears that the upper limit for the alternator output has gone up with the current firmware version.

 

[THAW]

As I stated in my earlier post my Jeep has been parked for several days and its been cold here in Indiana and my trip out yesterday resulted in my EVIC starting out at 14.7 and after a few hours out was down to 12.7.

So just as a test I got out my Motopower tester and did some quick tests on my two Full River 750-25’s in my dual Genesis setup and also tested the charging system.

After I did my tests I started the Jeep and my EVIC displayed 14.7 so I would be curious what the Jeep Engineers were thinking when they designed this complicated charging design.

Take a peek at the IBS data using JScan (it's in the Live Data for the Body Controller module) to find out what your Jeep thinks about the battery that has the IBS attached.

 

[WranglerMan]

Take a peak at the IBS data using JScan (it's in the Live Data for the Body Controller module) to find out what your Jeep thinks about the battery that has the IBS attached.

What would I be looking for?

 

[Mguy]

Take a peak at the IBS data using JScan (it's in the Live Data for the Body Controller module) to find out what your Jeep thinks about the battery that has the IBS attached.

What's your Intelligent Battery Sensor (IBS) data on voltage and temperature that provides insight on set JL charging parameters? Elsewhere on this forum, and now again, you've touted the benefits of using Jscan for reading data and analyzing battery/electrical subjects, but looking at your prior posts I can't find a contribution from you of any actual data from actual use of a JL. Without data from multiple users it's virtually impossible to separate what's normal and acceptable from what's bad equipment or bad programming.

 

[Mguy]

. . . . it's the PCM that controls the alternator that determines the charging voltage. . . .

And from charging voltage, if PCM parameters are known, a JL owner can know a lot of things--like whether a driving routine is adequate for charging, whether non-stock devises or modification are called for, or whether its time for vehicle service.

 

[THAW]

What would I be looking for?

I typically monitor these parameters:

Checking IBS Resistance and SOC might give you insight into whether your Jeep agrees with your tester about the need for charging.

With the vehicle running, the Current parameter shows the battery's charge acceptance rate (used by AGM chargers to determine charging stages).

In your case, remember the IBS is monitoring the Genesis AUX battery which isn't always connected to the Jeep (and otherwise acts in parallel with the primary Genesis battery to perform JL CR[an]K battery duties).

 

[WranglerMan]

I typically monitor these parameters:

Checking IBS Resistance and SOC might give you insight into whether your Jeep agrees with your tester about the need for charging.

With the vehicle running, the Current parameter shows the battery's charge acceptance rate (used by AGM chargers to determine charging stages).

In your case, remember the IBS is monitoring the Genesis AUX battery which isn't always connected to the Jeep (and otherwise acts in parallel with the primary Genesis battery to perform JL CR[an]K battery duties).

Well if I start the Jeep within 2 minutes of running the Cole Hersey relay tells the solenoid to connect both batteries as one so with that said would it still give me the correct info as once connected the IBS sees both batteries as one

 

[THAW]

Well if I start the Jeep within 2 minutes of running the Cole Hersey relay tells the solenoid to connect both batteries as one so with that said would it still give me the correct info as once connected the IBS sees both batteries as one

Not exactly. Current is measured for only the battery to which the IBS is attached. Most IBS calculations rely on current (A) data. The IBS does measure parameters that are effectively the same for both connected batteries, but for all intents and purposes it's only tracking one battery.

Also, the Genesis relay/solenoid potentially causes the IBS to not see any starter load, which likely affects its resistance calculation (I suspect the Genesis ignition wire accessory fixes this starter load "problem").

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