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Discussion Starter · #1 ·
Hmm, I've noticed some odd behavior both in max regen mode, and when braking normally. Sometimes I see the charge gauge suddenly go to 0 when braking or letting max regen... regen. It seems to happen most often when I modulate the brakes harder and softer rolling down a big hill with undulations. When it does, regen will only decrease down to 0, until I apply a little throttle, then it's normal again. Regen during cruise control doesn't seem to have this behavior.

Also, oddly, I can't turn max regen off when the charge gauge is at 0 - I wanted to try to see if that would fix it. I had to stop first. I repeated this a few times and it kept up, so it is either some persistent bug, or by design.

Anyone else have weird regen behavior? I'd rather not deal with dealers since everything else in my Wrangler works great.
 

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I remember reading that the 4XE does all these hidden things like when you hit the breaks, it could be applying regen instead of breaks.
It might also get upset if your batteries are really hot. I was using Electric only going 75 or 80 when it was 100f (40c) outside and it kicked on the motor at 20% and gave me an error, and max regen turned off.

I did got a tazer mini, and it will turn on the max regen every time you start the car. I also know that there is a debate in Selantis to have it in by default and that might come in a future update.

Z Automotive Tazer Mini Programmer - Compatible with Jeep Wrangler JL and Gladiator JT 2018-2021 Amazon.com: Z Automotive Tazer Mini Programmer - Compatible with Jeep Wrangler JL and Gladiator JT 2018-2021: Automotive
 

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Several times now I have experienced an event when I am braking and all of a sudden the force from the regen disappears and I have to really push hard on the brakes to stop. The charge/power gauge will also drop to zero. Then I took a trip to Colorado and lost all regeneration on the downhill sides of Imogene and Ophir pass. I managed to get some video...
The first is from Imogene Pass showing loss of regenerative braking and MaxRegen unable to turn off/on, with the loss also occuring with MaxRegen off. The second is from Ophir Pass showing the same behavior, and in addition esave wont start the engine to add engine braking. Sorry for the bouncing :)


 

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So what I do is disconnect the battery and the the purple 5v fuse in the drivers side front of the fuse panel. I let it sit for 15-30. Then re plug it all back in.


I’ve had to do it a few times for various reasons to figure things out.

I believe that when the batteries get too hot, a safety mechanism kicks in and stops all charging and discharge from the 17kw battery pack.

it’s a freak out don’t damage anything mode.
 

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Several times now I have experienced an event when I am braking and all of a sudden the force from the regen disappears and I have to really push hard on the brakes to stop. The charge/power gauge will also drop to zero. Then I took a trip to Colorado and lost all regeneration on the downhill sides of Imogene and Ophir pass. I managed to get some video...
The first is from Imogene Pass showing loss of regenerative braking and MaxRegen unable to turn off/on, with the loss also occuring with MaxRegen off. The second is from Ophir Pass showing the same behavior, and in addition esave wont start the engine to add engine braking. Sorry for the bouncing :)


did you see the regen indicator on the dash flash? Page 40 of the manual says it will do that when regen is not available but I didn’t see the conditions that make it unavailable. Might be helpful to understand what was happening at the time. Were you in 4l,2h, etc?
 

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did you see the regen indicator on the dash flash? Page 40 of the manual says it will do that when regen is not available but I didn’t see the conditions that make it unavailable. Might be helpful to understand what was happening at the time. Were you in 4l,2h, etc?
I have never had the regen icon flash when this happens, no message or CEL either. When this occurs in city driving I am in 2HI, and it drops out just long enough to almost rear end the car in front of me. In the videos above, I was in 4LO on Imogene and 4HI on Ophir and it seemed to take coming to a complete stop to reset.

I had installed a GeoTab prior to the Colorado trip to try and capture any codes that were thrown when it happens, but the Jeep never reported any related codes.
 

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@SpaceCase 4l I can understand as regen braking might be too aggressive at such a low speed but I’m just making that up, I don’t have any info to suggest that is by design. Not sure what would cause it in 2h, I have never experienced that symptom. @Wrangler4XEFan do you have any insight into when max regen is not available? Would be a good question for “ask the expert” since the manual doesn’t describe the conditions.
 

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Discussion Starter · #9 ·
Oh, cool, so it totally just isn't me! Well, not cool, but at least my Wrangler isn't broken in some weird and special way. I really do wonder if it's some thermal or charge limit thing - my Tesla will start limiting regen if you roll down a huge hill after a while, but it's smooth and you can tell since the regen indicator has dots on it to show the decreasing limit. The Wrangler just cuts all regen, just like in @SpaceCase's video.

I've personally seen this mainly in 2h/4h, 4low usually regens fine for me. Hmm, I should try to figure out if this weird stuff happens more with a hot battery - it certainly seems like it's by design, since there's no CEL when it happens.
 

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Discussion Starter · #10 ·
When this occurs in city driving I am in 2HI, and it drops out just long enough to almost rear end the car in front of me.
That's odd, my 4xE seems to use the friction brakes when this weird behavior happens. In max regen, it friction brakes for me, and if I'm the one braking it smoothly applies the regular brakes. There is a moment where there's no brakes while it switches sometimes - is that what you mean, or do you feel way less brakes period?

I also don't need to completely stop to reset, a moment of throttle - even a little - is enough. Just enough to remove all braking.
 

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That's odd, my 4xE seems to use the friction brakes when this weird behavior happens. In max regen, it friction brakes for me, and if I'm the one braking it smoothly applies the regular brakes. There is a moment where there's no brakes while it switches sometimes - is that what you mean, or do you feel way less brakes period?

I also don't need to completely stop to reset, a moment of throttle - even a little - is enough. Just enough to remove all braking.
I see this as two different events. The downhill loss acts just as you say, with the brakes acting as friction only. It is scary, however, when operating in electric mode and this occurs on a steep incline, as there is no engine braking. It almost feels like I am in neutral flying down the mountain. I couldn't test the throttle to reset, as I was always going too fast at that point.

The second event is even scarier. It was best described by bodhi on another forum, "I was slowing down to take a right hand turn, and I did have my foot on the brakes, and all of a sudden the regen braking was gone, and the pedal was super hard, and I really had to react quickly to avoid an accident." In this case, I do lose the ability to brake properly. It feels like the Jeep is expecting the regenerative braking to be there when it isn't, and does not let the friction brakes engage. I wish I could get this on video.

@Wrangler4XEFan, it would be great if you could get to the bottom of these regen issues on “ask the expert”!
 

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Discussion Starter · #12 ·
Yeah, that is scary... I guess I've only experienced the less-scary variant of the underlying issue.

I did go on a quick drive to try and reproduce the problem yesterday, with lots of accel/decel, brake modulation, max regen on/off... it all worked fine, ugh. I guess there's not much I can do now, other than agree that "ask the expert" would be nice for getting some details on how regen is supposed to work.
 

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Discussion Starter · #13 ·
(Reading the JL thread) Oh, interesting! I didn't think about ABS, I was on a loose dirt road when I experienced the issue. Hmm, I might have to do an experiment next time I'm on loose dirt or sand. I can see the control algorithm disabling regen, switching to friction and running the ABS when a wheel slips, that kinda makes sense.
 
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