Harsh transition to regen when canceling cruise control

Harsh transition to regen when canceling cruise control

I've had the car a couple of days and absolutely love it (obviously!)

The one thing I haven't figured out is how to smoothly turn off cruise control. I have regen set to my preferred 'strong' (normal) level which works great when driving around using the accelerator, but causes problems when using cruise control.

In 'normal' cars, you can either disable (pause) cruise by pressing a cruise button or feathering the brake pedal. Ditto in the Model S. OK so far.

BUT - in ICE cars there is no regen so when cruise is paused the car starts a gradual slow down. In the S that car immediately starts an aggressive deceleration.

Anyone figured out a good technique to smoothy disable cruise? There is so much torque that trying to get the accelerator pedal into just the right spot to enable a smooth transition when disabling cruise has proved elusive so far.

tranhv68 | 4 gennaio 2013

the default setting is high regen. try setting it to low regen and try using the cruise control again.

Oliver in Seattle | 4 gennaio 2013

I think they could do some firmware enhancement to smooth all the transitions with the cruise control. If you increase the speed it also jumps up aggressively. 'Fading' to the new setting over 2-3 seconds might be a nice option.

DouglasR | 4 gennaio 2013

Try pressing slightly on the accelerator at the same time you shut off cruise control, then backing off gradually on the accelerator.

Sudre_ | 5 gennaio 2013

Same problem with a manual car. All my previous cars except the one I have now were manual. When I just turned the cruise off the manual ICE slowed briskly. Over time I just learned where to put my foot on the accelerator before turning the cruise off. Just takes practice.
Since the subject is now coming to light maybe Tesla can put something in the next software update to smooth the transition.... maybe a few seconds of coast before Regen kicks in when shutting off cruise. Maybe make a request in the software update topic.

BYT | 5 gennaio 2013

What software version are you all experiencing this on? I still have 3.0 and wonder if it's a 4.x thing? My cruise to regen hasn't been an issue for me so I asked.

nickjhowe | 5 gennaio 2013

I've got a performance model running 4.0. The regen on 'normal' is significantly stronger than the non-perf car I drove at Get Amped. I like the high regen 95% of the time, it is only during the 'disable cruise' scenario that I've found it to be a problem.

@DouglasR - thanks. I was going to try this; maybe with a bit of practice I can smooth out the transition.

GeekGirls | 5 gennaio 2013

I find it helps to put light pressure on the accelerator for a moment before disengaging cruise, which works like a charm.

Velo1 | 5 gennaio 2013

It sounds like there is a definite learning-curve on a number of features with the Model S. Like the car, we need to think outside the box, so to speak.

Volker.Berlin | 5 gennaio 2013

I think they could do some firmware enhancement to smooth all the transitions with the cruise control. If you increase the speed it also jumps up aggressively. 'Fading' to the new setting over 2-3 seconds might be a nice option. (Oliver in Seattle)


Robert22 | 5 gennaio 2013

I'm confident this will eventually be smoothed out with a software tweak. The lady of the house shouldn't need to worry about her sunglasses flying off when she disables cruise control.

nickjhowe | 5 gennaio 2013

I tried the 'light pressure on the go pedal' technique and it works OK at freeway speed. The real problem is a slow speeds. I like to put cruise on when I'm in a 30 or 35 zone so I don't speed. The problem is that momentum is proportional to velocity squared so the regen is REALLY powerful at 30mph compared to 70mph. It is much more difficult to get a low speed transition.

Chuck Lusin | 5 gennaio 2013

I would think that the fading over 2-3 sec might be ok, as long as there was an instant off, if the break is pressed.

DTsea | 5 gennaio 2013

nickjhowe, actually momentum is proportional to velocity- momentum=mass*velocity. You are thinking of kinetic energy- Ek=.5*m*v^2 which is relevant for stopping distance with friction brakes (since they dissipate energy at a constant rate, the deceleration is maximum when speed is low).

If kinetic energy absorption to regen were the issue, the regen would be mild at speed and strong when slow (like brakes).

The issue is not momentum- the issue is that regen response is nonlinear. It is mild if you just let up the accelerator a bit; if you take your foot completely off it is strong and the brake lights actually go on! So if you disengage cruise without your foot on accelerator, the car thinks you are trying to stop. It's like jamming the brakes.

Brian H | 6 gennaio 2013

So guesstimate where the goose pedal would be at current speed before disengaging, and put it there with the right foot! Practice makes perfect. So guesstimate where the goose pedal would be at current speed before disengaging, and put it there with the right foot! Practice makes perfect.

Brian H | 6 gennaio 2013

Oops. Double pasted. Howdid that happen? Dang "validation errors"!

jkirkebo | 6 gennaio 2013

Yep, that's how I do it in the Leaf. Finding the correct spot on the accelerator pedal quickly becomes muscle memory, I do not have to think about it anymore.

Richard_P85-Grey | 6 gennaio 2013

A work-around is instead of cancelling the cruise control pull the stalk down to reduce the set speed by 5 mph. The transition is gentle allowing you to take control with the accelerator. Finally cancel the cruise control. However I hope Tesla changes the software to make this work-around unnecessary.

nickjhowe | 7 gennaio 2013

@DTsea - you are right. Basic error on my part. Long time since I did physics at school. Whatever the reason, it is still much more problematic at low speed (c.30 mph) :-)

mkh1437 | 7 gennaio 2013

The other annoying thing about this behavior is that the brake lights likely turn on when the "aggressive regen" kicks in. I always feel like the person behind me is going to think I'm riding the brake. I know I am always irritated when I see someone who appears to be two-foot driving... either accelerating or braking. There is no "coasting" in the Model S, unless you employ one of the methods suggested here (e.g., feathering the Go pedal).

Michael37 | 7 gennaio 2013

I'm also bothered by this behavior. I've learned to work around it by rolling in a little accelerator pressure before I disengage cruise, provided that I have enough time to do that, but it would be much preferable if the car would bring the regen on slowly in this situation.

olanmills | 8 gennaio 2013

This bothered me too at first. Now I just make sure to push down on the accelerator before turning of the cruise control. Of course, this isn't perfect as I can't be sure exactly how far to push the accelerator unless I push it far enough to actually speed up a littler beyond the cruise control setting and then turn cruise control off, but that's not always something you can do depending on the situation.

I like the idea of cruise control "easing off" as Oliver described. However, I think that it should still cut off completely if you use the brake pedal, in case you need to stop or slow dramatically. "Fading" out though if you push the switch would be a great option.

Also, on an unrelated note, I wish that stupid light on the lever could be disabled.

Mel. | 9 gennaio 2013

Olanmills, push the lever in , light should go out.

nickjhowe | 9 gennaio 2013

@olanmills - re the light - that was the first thing I thought, but after a couple of night-time drives it isn't anywhere near as bright as I was afraid it would be, and it doesn't bother me. I actually like it now.

olanmills | 9 gennaio 2013

@Mel, I'm not sure if that's supposed to be a joke or not.

I understand that you can turn the cruise control system off by pushing the lever in, and then the light goes out, but the light stays on when the cruise control system is on.

I find the light annoying, and unnecessary given that the screen already shows you that the cruise control system is on, even if it not currently active, with the little white arrow.

Mel. | 9 gennaio 2013

Olanmills,, no joke, I had that light on all the time. I finally pushed the lever in, I was not using cruise control. I do not use cruise control except on trips, thought your situation might be similar,.

olanmills | 9 gennaio 2013

Ah, no worries. Yeah, I am saying that even when you are using cruise control, I find the light kind of annoying. It's not the biggest deal in the world though...

nickjhowe | 9 gennaio 2013

Small piece of black electrical tape...

Brian H | 9 gennaio 2013

Black tape?

Mark E | 9 gennaio 2013

Manual ICE vehicles have the same behaviour when cancelling cruise control. You simply put some pressure on the accelerator to match speed and then cancel. I've been doing that for years without a problem. Then again, I don't like automatic cars because of the wafty horrible habit of coasting when you back off rather than the immediate response of a manual.

This with regen makes the electric drive so much nicer.

Ryan M | 24 aprile 2014

I was searching the forums to see if anyone else had this same complaint and ran across this old thread.

There is a stretch of road I commute that has a low speed limit and is heavily patrolled and ticketed, so I have always favored cruise control as a way to keep my eyes on the road instead of the instrument panel. In my Tesla disengaging the CC is a jolting prospect, and while I have learned to compensate with the accelerator, it would be nice to have it fade.

Also, the CC seems to be hypersensitive. When driving a road with rolling bumps (like the 405 freeway in the Valley), the CC senses the slow down from hitting a bump and immediately accelerates. As the car comes down the other side and accelerates, regen engages. I end up with speed oscillation for 3-5 seconds after bumps like this. I've never experienced this in another car, probably because the acceleration delay in an ICE is just long enough.

It seems like the CC could benefit from some stronger low-pass filtering or a small (100-200ms?) delay. Does anyone know if this is something Tesla has looked at? I can't find anything in the "feature" threads.

NKYTA | 24 aprile 2014

@Ryan, if you select "low" regen on the control panel the regen won't be as agressive, which sounds like it solves one of your issues.

hillcountryfun | 24 aprile 2014

I would love to see the option added such that when you set the cruise control the system would also "optionally" set the regen to low. And change it back when the cruise is disabled. I think it would help quite a bit.

SamO | 24 aprile 2014

+1 hillcountryfun

Great idea. Also agree with NKYTA that low regen is a lot less jarring than strong regen when disengaging CC.

jordanrichard | 24 aprile 2014

What I have been doing is putting my foot on the accelerator with out putting pressure on it and then tap the brake to kill cruise control, then immediately put pressure on the accelerator and ease her down. It helps if you have experience with driving a stick shift because it's like letting out the clutch as you give it gas.

SoCal Buzz | 24 aprile 2014

+1 slight pressure on accelerator solves the problem.

Bob W | 24 aprile 2014

I like the way the car slows down rapidly when you disengage the cruise control, and I sure hope they don't change it, otherwise I'll have to use my brake lot more. If I want to slow down slowly, I just hold down the accelerator with my foot before I disengage the cruise control. With a little practice, you can slow down as slowly as you want.

BTW, did y'all know that the cruise control has a very nice 5 mph up/down feature? Move the CC stalk up or down a lot (to the stop), and the CC speed goes up or down by exactly 5 mph instead of by 1 mph. Speed limits tend to go up and down in 5 mph increments (at least around here), so this feature is really very handy.

Finally, yes, similar to the bumpy road issue, I noticed that with CC on in heavy rain on the freeway (bad idea), whenever I hit a big puddle, the car really did seem to fight the deceleration with a sudden acceleration. So yes, thanks to instant torque the CC does operate much more aggressively than in any other ICE car I've driven, so be careful out there.

Mark E | 24 aprile 2014

My experience driving the Roadster with cruise control was very similar to driving a manual car with cruise - apply pressure to the accelerator before cancelling if you want it smooth. I suspect that putting any kind of 'fade' into the cancel could scare people into thinking that the cruise wasn't cancelling if there wasn't some kind of indication.

Captain_Zap | 24 aprile 2014

The cruise control deceleration has been adjusted since the OP and it is more refined. I think the change impacted overall deceleration rates at higher speeds.

David Trushin | 24 aprile 2014

I keep my foot on the accelerator and use the wand to turn off the cc. Works very smoothly.

Tâm | 24 aprile 2014

I prefer to maintain the meaning of regenerative brake as in an abrupt "slow down" whether by discontinuing the accelerator or the cruise control.

I should feel an instant "slow down" which makes the use of conventional brake pedal unnecessary in most of cases.

As David Trushin recommends, if you want a smooth brake, then apply the accelerator to control the speed of slowing down.

Brian H | 24 aprile 2014

React in advance with your foot on the goose pedal.

Rocky_H | 25 aprile 2014

@Ryan M: I have also noticed that uncomfortable aspect that a bump instantly causes the car to accelerate hard. I think it would be quite reasonable to have some kind of slight filtering for those very quick instances.