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Discussion Starter · #61 ·
Now I'm confused. In your original post, I thought you said it went to 12.6 while driving. It's normal for it to go between mid 13s to mid 14s. That part is all determined by temp of the battery. If it was going into the 12s while stopped and ESS was activated, that's also normal. If it goes I to the 12s while the engine is running, that is the only issue. If its not doing that, you are fine.
It stays in the 12’s most of the time running unless you are off the throttle, the charging number I gave is when it is charging when coasting. I don’t know how it monitors the temp of the battery. It sounds like you are saying the battery temp is what determines the charging levels. The info Jeep gave the techs says something different. We will see, I am just gonna drive it and see
 

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The battery temp is monitored by the IBS (intelligent battery sensor). It's the thing with a plug on it on the negative battery post. Using a good scan tool, or something like obdlink software, you can read all those parameters. The chart Tyler posted earlier is the targeting charging voltage at each temp. Generally, the colder the battery, the higher the volts. It maxes at 14.4, and minimum is 13.6. A battery will charge to the maximum charging voltage with as many amps as possible. When it hits that voltage, the amps will start to back off to not exceed that voltage. Even a 100 perfect, fresh off the charger battery will pull the target voltage, but just push a very small amount of current. Dealerships get vehicles mixed up all the time. If they drove something with thr 4xe (which is a plugin hybrid) then it would probably do what they were saying. It would also have regenerate braking.
 
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I am going to do that at 3 o’clock today. I am going to go straight there after work. I want to see it for myself. I plan on taking a 1,000 mile road trip and I want to make sure.
And get some different opinions from a different dealer...😉😎
 

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Discussion Starter · #66 ·
Well folks I went to 2 different dealers, I test drove a 2021 and talked to a tech and spoke with a service dept at a totally different dealer. I did not get to drive the 2021 model they actually took me for a ride. The 2021 was at 14.4 volts at idle and all RPM's for the first 5 minutes and then dropped to 12.8 volts and would only charge when off the gas and slowing down in our less than 10 mile drive. The tech that installed my alternator said that 2020-2021 models " can have a standard alternator or a smart generator with SAM charging", He also said the alternator is the same it is all with the computer. I want to trust him because he does this for a living and has factory resources. The second dealer is a very large dealer and actually sold my Jeep when it was new and was very familiar with this type of charging system and said it is hit or miss if the vehicle has it or not.

The only thing I can do is just drive it and hope I am being told the truth. The service shop at the second dealer provided me with the same paper I posted here using my VIN number. I feel like I am suspect of a cheating spouse and trying to find out the truth at this point LOL. I have never had a cheating spouse and I have married forever though. I will report back in a few weeks. On a side note we have a low of 25 here in FL and people are worried about crops and they are saying snow in north FL.

I am very grateful for the help here. I am not saying any of this is really true it is just what I have been told. Stanger things have happened....Scott
 

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I would suggest you get an OBD monitoring device like the OBDLINK MX+ and monitor the battery. So you know exactly what the parameters are. My 2021 does not ever get in to the 12v range when running ever. I also don't think the tech talking about alternators being smart and not is correct. The alternators are the same and there should not be differences among the same vehicle.
 

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At this point the dead horse has been properly beaten. You have a new alternator, a new battery, and a functioning ESS system. A test drive of another 2021 has confirmed the behavior you see on yours. And a quick search of the Mopar parts site does indeed show 2 different alternators available for Latitudes, although the descriptions do not say what the differences are.

So if it was me I would just stop looking at the damn gauge and enjoy my Cherokee. ;)
 

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At this point the dead horse has been properly beaten. You have a new alternator, a new battery, and a functioning ESS system. A test drive of another 2021 has confirmed the behavior you see on yours. And a quick search of the Mopar parts site does indeed show 2 different alternators available for Latitudes, although the descriptions do not say what the differences are.

So if it was me I would just stop looking at the damn gauge and enjoy my Cherokee. ;)
I am surprised by these findings, yet I try to always keep an open mind so... why not ? Proven in a second Cherokee, can't ignore that. I just wish we had official technical info available, clearly linked to KLs, to better understand the tech.

You did good investigating there @Ocracokenc . Time to enjoy the Jeep now, and the spouse ;)
 
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Yep, what they all said. I guess we all still learn something new everyday...Everything is working, I wouldn't worry about, mission accomplished...😉😎
 

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The 2021 was at 14.4 volts at idle and all RPM's for the first 5 minutes and then dropped to 12.8 volts and would only charge when off the gas and slowing down in our less than 10 mile drive.
Looks to me like a way to increase MPGs. Top-off charge when first starting and/or battery low, then only charge when off the gas. I'll bet heavy ESS would keep it around 14.4vdc for a while.

It's a bit like regenerative braking in the EVs.

I'll have to see if it does this in my 2019 TH/E.
 
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@15THgobrrr : not to put you on the spot or anything... but have you heard about this ? Smart alternators or whatever they call it, in Cherokees ? Thx...
 

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@15THgobrrr : not to put you on the spot or anything... but have you heard about this ? Smart alternators or whatever they call it, in Cherokees ? Thx...
Not so sure it's a "smart alternator", but rather a "smart PCM". From post #9 in this thread:

The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM. This circuitry is connected in series with the second rotor field terminal and ground.


Makes sense to me the PCM can effectively lower the voltage by lowering the current provided by the alternator.
 
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Not so sure it's a "smart alternator", but rather a "smart PCM". From post #9 in this thread:

The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM. This circuitry is connected in series with the second rotor field terminal and ground.


Makes sense to me the PCM can effectively lower the voltage by lowering the current provided by the alternator.
That makes sense. One day, maybe, we'll get substantial documentation on this.
 

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Discussion Starter · #75 ·
At this point the dead horse has been properly beaten. You have a new alternator, a new battery, and a functioning ESS system. A test drive of another 2021 has confirmed the behavior you see on yours. And a quick search of the Mopar parts site does indeed show 2 different alternators available for Latitudes, although the descriptions do not say what the differences are.

So if it was me I would just stop looking at the damn gauge and enjoy my Cherokee. ;)
Lol, my gauge watching days are over. I will say when the Jeep is slowing down and it goes to 14.4 volts I can feel a slight increase in drag. The tech said it free’s up around 5 HP. I wish Jeep had a way to contact them and confirm it. I know this doesn’t apply here but my friends Audi SUV charges the exact same way and it is not a hybrid.
I tried to get better documentation for you guys but the papers I posted earlier was all they could give. I am gonna keep digging but not let it bother me. I am sure if you guys dig up something it will get posted up. All the best
 

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Discussion Starter · #76 ·
Looks to me like a way to increase MPGs. Top-off charge when first starting and/or battery low, then only charge when off the gas. I'll bet heavy ESS would keep it around 14.4vdc for a while.

It's a bit like regenerative braking in the EVs.

I'll have to see if it does this in my 2019 TH/E.
They did say it is 100% MPG driven tech
 

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I'll bet heavy ESS would keep it around 14.4vdc for a while
I wonder how many times I need to tell people that voltage does not indicate whether the battery is charging or not!!!!!

Example

14.2v charging at 22 amps



14.2v charging at 111amps



So can someone explain to me how they can assume based on voltage that the battery is charging or not? You can't

Just because someone is a tech at a dealer doesn't mean they are the authority on how things works. They follow procedures set out by Stellantis. There is no fancy regen feature, there is no clutch in the alternator, its giving the same resistance and spins at the same speed as the engine does (the idler pulley).
 

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Just because someone is a tech at a dealer doesn't mean they are the authority on how things works.
You got that $#*t right!!! They apparently barely know the difference between the engine, and the transmission...😳😎
 

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Would you look at that, instead of theories and trying to think the vehicle has some fancy regen feature.......it doesn't. Simply monitor the IBS and that will tell you 99% of the time what kind of issue you are looking at whether it's battery or charging system related.
Also of note is the last paragraph, large amounts of charging current delivered after an ESS event if the battery is low, this mirrors exactly the behavior i've been able to monitor on my vehicle.
 
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