Rumble in re-gen mode.

Definitely not normal. Anything other than electronic humming is unexpected.

 

It sounds like this the only Clarity your dealer has ever seen. It's not normal.

 

The only thing I can think of that could be even remotely related is my Clarity doesn't like me using paddles (i.e. down the hill I live on) when the SOC=100%. The car "stutters" a little for lack of way to describe it. The fix in my case is simple- don't use the regen paddles going down the hill when the state of charge is full. The brakes never cause a problem. Of course the car will turn on the gas engine if it gets too much charge coming down the hill. What I do to mitigate (i.e. winter) is turn the heat way up so i'm not too close to 100%. In the spring/summer it just runs the gas engine. I rarely need AC at all where I live.

 

This is a longshot, but a forum member had a bad engine mount a while back. I think it manifested itself as a 'clunk' when on a hill and shifting from Park to Drive.

But, I can imagine a bad engine mount (when it is heavily loaded by regeneration) could result in metal-to-metal contact. This would transmit any vibrations (which are normally dampened by the rubber) directly into the body, possibly sounding like a rumble.

Purely a guess, but that was an elusive problem that he spent quite a lot of time trying to get diagnosed correctly.

 

Curious behavior. My conditions slightly different but behavior much different: Level ground, always HV mode from start with 100% charge: By the time I get down the driveway and to the end of the small county road on which I reside, all told about 7/8 mile and normally about 97% charge despite HV from the git-go, under 30 mph, paddling to full (4 bars) regen begats flashing bars and an immediate regression to the 2-bar regen state.

 

Talked about a long time ago. When I got my Clarity, like many I think, the traction battery was on 0, and likely been that way for long time. The dealer told me they knew nothing about Clarity and didn't want to sell it, but it came with their allocation of other cars. Anyway, maybe related maybe not. Even my test drive did what we call angry bees. SOC was likely near 0%. I did get $2500 off MSRP and bought the car. Took it home, charged it, and of course the electric experience is WAY better. Sad that the dealer made no effort to maintain the battery state.

Anyway, first about six months of ownership, I'd charge the car fully and drive to PDX (about 109 miles from Eugene, all flat interstate) and my EV range would drop to zero even with HV on all the time. I didn't know this wasn't normal. HV is supposed to try and maintain SOC. My SOC routinely went to 1 bar on the EV range bars, which is also anomalous. Most Clarities when they get to 2 bars stop, and the car automatically does hybrid mode. Nothing doing on my car. The engine would rev like it was going to go ballistic. Anyway, lots of behavior suspect few on these forums have ever seen. For example, my Clarity could never do 'gear' mode where you see the gear icon in the middle of the energy info screen.

Kentucky Ken on these forums (now a few years ago) asked me to reset my car by removing the 12v negative terminal, then replacing it. While this doesn't actually hurt anything you do see scary warnings for a few miles. After doing this once, my car started showing the gear icon on straight drives (like I5) and amazingly now mostly preserves SOC when in HV mode on the highway. I lose a bit even when not stopping, but say never more than 10-30% of beginning SOC if I'm religious about keeping it in HV mode. I also now never let EV go to zero. I've learned to use HV Charge anytime my EV range gets low.

Car's been great, works pefectly now (or as perfectly as it can and good enough for me). I get good gas mileage when in HV mode (~40mpg on average). My commute daily is fewer than 25 EV miles, so I can mostly go all EV although do burn gas in the winter time. My all-EV range is about 22 miles now, 5 years in.

-Dan

PS: I do think even post-reset, my experience isn't same as everyone else. I do need to 'train' others who drive my car. That is to say, I have a piece of paper on the drive button that says 'press HV' before starting out. It keeps them from having a bad experience with my car and is just simpler. I play the game of using as much EV-only miles as I can, but don't expect anyone else to. My car has never been "OK" running on 0 EV miles, and still isn't. Luckily relatively easy to avoid that.
One last thing: Not willing to test 0 EV even for "science" sake. I think it literally hurts my car to do so. That's off the table now. I just don't allow it to ever happen.

 

I also wanted to add something strange to the topic.
Touring 2020, behaving absolutely normally for years until I left it for vacation for couple weeks. What I was away, oil at ATF were changed.
Came back and took fully charged car for a drive (on a cold day, but not freezing).
Normally it will go to 0 EV kilometers on a guessometer and jump into hybrid mode by itself.
This time when I had about 6 EV km left, she turned off the leaf, and switch to HV mode, and was trying to maintain that 6 km, running the engine.
It failed, dropped to 0, engine still running until I plug it in my garage. Never happened before.

Sometimes I did it myself - switch to HV when I had several EV kms left, but this time car did it for me, like she learned from me I have no other explanation.

(not sure if it is related - on the day I left my cat sh-t in the walkway instead of a litter box, and the next day as well. Never happened before. Maybe they both missed me? : )

 

Alex800st, I think we are talking about a similar phenomenon. What I mean is the car is supposed to figure out how to automatically do hybrid mode when needed. There's some set-point where the car just does its thing as need be. In your case, and in the cold it turned on the gas engine/EV "early" and I suspect the problem I've witnessed is the opposite. Meaning the set point is too low, and when the gas engine finally turns on, it cannot recover (reason for high revving which I believe unusual, not the "normal" high revving some have heard). Anyway, the fact that I basically never let EV use the last 10 miles of estimated range (unless I know I'll be home to plugin shortly) keeps me out of that issue completely. The car works fine otherwise, so I don't have other weird problems, just the one problem which I find easy to avoid.