Model 3 - 2018.42.x Regen Issues

[rdturner0]

I'm wondering if anyone else is seeing this.

On two occasions, we noticed that regen is dramatically reduced, usually above 50km/hr. This loss of regen has not been accompanied by a warning, nor associated with any of the normal situations where regen is limited (cold battery, battery too full, etc).

To me this is safety issue, as at random occurrences, you end up trying to slow down and almost hitting the car in front if you aren't really paying attention. Especially since there isn't a warning indicating that regen is limited.

In both occurrences we've had so far, the problem has gone away on subsequent "drives".

This was not a problem before the 2018.42.x update (at least not that we had encountered).

(rant on)
The correct behaviour for when regen is limited is to simulate the regen braking with the regular brakes, so that the driving profile is more or less the same in either situation. Otherwise, you cannot reliably "one foot drive" the car. I'm expecting there are some sort of technical or possibly safety issues with doing this as it seems like a major oversight to me.
(rant off)

 

[talkingevs]

Same here. I posted something on this yesterday and was told it's because the temps are dropping outside.

 

[Kirby64]

I'm wondering if anyone else is seeing this.

(rant on)
The correct behaviour for when regen is limited is to simulate the regen braking with the regular brakes, so that the driving profile is more or less the same in either situation. Otherwise, you cannot reliably "one foot drive" the car. I'm expecting there are some sort of technical or possibly safety issues with doing this as it seems like a major oversight to me.
(rant off)

I would strongly disagree with this. Part of the reason the brake pedal feel is good on these card is they don't do blended brake pedal stuff. Regen is throttle controlled, brake is for brake caliper control. You just need to get used to it. Just like when you use an ICE car for awhile, using the brake a lot more isn't the end of the world.

 

[MP3Mike]

Have you put winter tires on? If so, there is another thread covering the issue of winter tires causing a loss of regen. I think Tesla has said that it can take a lot of driving for it to learn the properties of your tires and re-enable an appropriate level of regen.

 

[SomeJoe7777]

Have you put winter tires on? If so, there is another thread covering the issue of winter tires causing a loss of regen. I think Tesla has said that it can take a lot of driving for it to learn the properties of your tires and re-enable an appropriate level of regen.

I apparently experienced exactly this in my RWD 3LR. The new winter tires had the tread release compound on them when brand new, and the car backed off the regen during the first 200-300 miles of driving, especially in the 40-30 MPH range. Once the tread release compound had been rubbed off with enough driving, the car slowly "learned" (?) that the tires could take more regen without slipping and it returned to normal.

On a side note, that tread release compound had affected the tires' grip pretty bad, I was actually disappointed in the tires when I first put them on, especially in wet conditions. It's now been 500 miles and they're now nicely grippy in the wet.

The news that the regen algorithm is adaptive to the tires' traction is new to me ... I have not heard this before, nor do I have any proof of it. But the theory happens to exactly match the facts of what I have seen over the last month.

The long thread covering this issue is here:

Who has lost regen with winter tires?

I haven't seen this thread because it's in the Canada forum which I don't normally watch, but I'm reading it now.

By the way, this is not a v9 software issue, as I experienced this issue under 2018.36.2, which was still v8.

 

[rdturner0]

I would strongly disagree with this. Part of the reason the brake pedal feel is good on these card is they don't do blended brake pedal stuff. Regen is throttle controlled, brake is for brake caliper control. You just need to get used to it. Just like when you use an ICE car for awhile, using the brake a lot more isn't the end of the world.

As far as I can tell, this isn't true -- pressing the brake pedal doesn't apply the calipers if regen can handle the required negative forward acceleration. In most cases, it's using regen..

This is absolutely the incorrect behaviour IMHO as it changes the driving profile -- imagine if sometimes you pressed the brake and it only sometimes braked normally, and sometimes it didn't. Completely wrong. Imagine if sometimes you pressed the accelerator and it only sort of went faster. It's inconsistent and unsafe behaviour for the vehicle. I like the car, but this is a safety engineering issue IMHO.

 

[rdturner0]

Have you put winter tires on? If so, there is another thread covering the issue of winter tires causing a loss of regen. I think Tesla has said that it can take a lot of driving for it to learn the properties of your tires and re-enable an appropriate level of regen.

Nope, no winters, not cold enough, normal roads, no traction issues, not a cold battery, etc, etc..

 

[rdturner0]

I apparently experienced exactly this in my RWD 3LR. The new winter tires had the tread release compound on them when brand new, and the car backed off the regen during the first 200-300 miles of driving, especially in the 40-30 MPH range. Once the tread release compound had been rubbed off with enough driving, the car slowly "learned" (?) that the tires could take more regen without slipping and it returned to normal.

On a side note, that tread release compound had affected the tires' grip pretty bad, I was actually disappointed in the tires when I first put them on, especially in wet conditions. It's now been 500 miles and they're now nicely grippy in the wet.

The news that the regen algorithm is adaptive to the tires' traction is new to me ... I have not heard this before, nor do I have any proof of it. But the theory happens to exactly match the facts of what I have seen over the last month.

The long thread covering this issue is here:

Who has lost regen with winter tires?

I haven't seen this thread because it's in the Canada forum which I don't normally watch, but I'm reading it now.

By the way, this is not a v9 software issue, as I experienced this issue under 2018.36.2, which was still v8.

For me it's not a traction issue like in your case. I'm aware of the regen being traction sensitive, and it's not the case for me when this issue occurred. Car has been working just fine for regen, except since 2018.42 update, and except for noted warnings related to full or cold battery.

 

[BobAbooey]

For me it's not a traction issue like in your case. I'm aware of the regen being traction sensitive, and it's not the case for me when this issue occurred. Car has been working just fine for regen, except since 2018.42 update, and except for noted warnings related to full or cold battery.

Maybe the 2008.44 update fixed it....

 

[DDotJ]

I'm having the same issue, even in the warm 80 degree California weather after driving 20+ miles. IIRC my car has been doing this since I got it, I was wondering if I should call Tesla Service.