Regenerative Braking - regen

[Adopado]

Moderator comment - this thread spun off from Features we didn't know we wanted?

Hopefully a new icon on the main front screen to simply switch between strength of regen braking . I prefer min regen on motorway driving and max regen in city driving. The former activates the brake light everytime i ease off the accelerator and drives the car behind me crazy. You currently need to 3 icon presses to do that on the M3. You can alter the strength on the flappy paddle on the Kona and is really useful.

So you're saying minimum regen causes the brake lights to come on frequently?

 

[tess19]

So you're saying minimum regen causes the brake lights to come on frequently?

With the strongest regen, the brake light always come on as soon as you lift off the gas pedal.

 

[MrBadger]

With the strongest regen, the brake light always come on as soon as you lift off the gas pedal.

I don't think I ever take my foot off the accelerator, except for final stop. We decelerate by feathering the accelerator at whatever rate is needed to slow. As brake light is controlled (whether exclusively or not?) by an accelerometer, gently lifting in standard regen mode will yield the same results (braking and brake light) as a larger lift in low regen mode.

 

[DJP31]

With the strongest regen, the brake light always come on as soon as you lift off the gas pedal.

The brake lights come on when the car is decreasing in speed by a prescribed amount. It doesn’t matter whether that speed reduction is caused by regen, the brake pedal or a combination.

It’s perfectly possible to reduce the pressure on the accelerator on the motorway and not trigger the brake lights.

 

[AllanO]

With the strongest regen, the brake light always come on as soon as you lift off the gas pedal.

If you lift the foot enough to cause a strong deceleration, I assume it is because you want a strong deceleration. Why else lift the foot?

If you cause the car to make a strong deceleration, of course the brake lights will have to come on.

 

[Adopado]

With the strongest regen, the brake light always come on as soon as you lift off the gas pedal.

Right ... I think you had it back to front in your previous post. (Actually the amount of retardation is controlled by your accelerator so even on strongest regen setting you can decelerate as gradually as you choose ... with the brake lights therefore not coming on. The only difference is with AP which does tend to lift off a bit sharpish in my experience.)

 

[15Peter20]

The brake lights come on when the car is decreasing in speed by a prescribed amount. It doesn’t matter whether that speed reduction is caused by regen, the brake pedal or a combination.

It’s perfectly possible to reduce the pressure on the accelerator on the motorway and not trigger the brake lights.

They must also be triggered by either the brake pedal or a calculated retardation/holding torque right?

If the car is stationary with the brake pedal depressed do the brake lights come on?

 

[Adopado]

They must also be triggered by either the brake pedal or a calculated retardation/holding torque right?

If the car is stationary with the brake pedal depressed do the brake lights come on?

Yes, of course. Many models use a combination of retardation and pedal to operate the flashing hazards when braking strongly for example.

 

[mpandrew]

Hopefully a new icon on the main front screen to simply switch between strength of regen braking . I prefer min regen on motorway driving and max regen in city driving. The former activates the brake light everytime i ease off the accelerator and drives the car behind me crazy. You currently need to 3 icon presses to do that on the M3. You can alter the strength on the flappy paddle on the Kona and is really useful.

Agree, I like to think I'm an ok driver but notice now that I'm 'braking' for pretty much every bend in the road despite not touching the brake for the entire journey. I remember being irritated by those drivers that brake for every corner and stop at every roundabout, now I've become one due to how regen works!

 

[AllanO]

I remember being irritated by those drivers that brake for every corner and stop at every roundabout, now I've become one due to how regen works!

You are the one responsible for, how fast your car slows down. The more you lift your foot from the accelerator, the faster the car slows down.

So if you think you are slowing down too fast, why don't you simply stop doing that? Why blame the way regen works?

 

[DJP31]

Agree, I like to think I'm an ok driver but notice now that I'm 'braking' for pretty much every bend in the road despite not touching the brake for the entire journey. I remember being irritated by those drivers that brake for every corner and stop at every roundabout, now I've become one due to how regen works!

It's not how regen works that causing the brake lights to come on. The brake lights only come on when the car's speed is decreasing at or beyond a certain rate. E.G. I followed a vehicle today and its' brake lights were coming on as it slowed down, mine didn't as I was maintaining a sufficient distance to just ease off the accelerator. Regen was cutting in at a max of circa 25kW and I was paying particular attention to the avatar of the car, no brake lights.

 

[Adopado]

Agree, I like to think I'm an ok driver but notice now that I'm 'braking' for pretty much every bend in the road despite not touching the brake for the entire journey. I remember being irritated by those drivers that brake for every corner and stop at every roundabout, now I've become one due to how regen works!

Please don't take offence but I think you need to develop the one pedal driving technique. It is different. You can either "brake" or "coast" or anything in between depending on how gradually you lift off the pedal ... you shouldn't be "braking" any more than you choose so the brake lights won't be coming on any more than they would with any other car. The problem is that we've all just been lifting off the pedal fully for however many years of driving so it takes a bit of practice to make the most of the one pedal technique. At it's most extreme you can inadvertently make your passengers seasick if you just lift off completely all the time!

 

[OneTinyFish]

The M3 regen (is this the same as with other Tesla models?) is strong and takes a fair bit of getting used to.

I would like to thank the very many nameless drivers I have overtaken who thought I was immediately brake-checking them.

 

[mpandrew]

Please don't take offence but I think you need to develop the one pedal driving technique. It is different. You can either "brake" or "coast" or anything in between depending on how gradually you lift off the pedal ... you shouldn't be "braking" any more than you choose so the brake lights won't be coming on any more than they would with any other car. The problem is that we've all just been lifting off the pedal fully for however many years of driving so it takes a bit of practice to make the most of the one pedal technique. At it's most extreme you can inadvertently make your passengers seasick if you just lift off completely all the time!

None taken , but the reality for me at least is after driving the car for over a year and used one-pedal since the day it was offered it isn't quite right IMHO. The drive itself is lovely, very easy to modulate speed and I don't simply lift off each time I want to slow, I am feathering the power. However I maintain that when slowing the car at a deceleration similar to what I used to driving an auto BMW e330, the brake lights illuminate. So unless I fully engage Driving Miss Daisy mode (future option?), the cars behind see a lot of brake lights from me where previously my smooth driving in an ICE vehicle would not have done this. Therefore upset those behind by constant brake lights or upset those behind by driving so gently I'm failing to make 'normal' progress. I guess the third option is to stop overthinking it, just drive the f*** thing and to hell with worrying about everyone else but that seems a little too much the norm these days, better to be considerate I think

 

[Adopado]

However I maintain that when slowing the car at a deceleration similar to what I used to driving an auto BMW e330, the brake lights illuminate.

Ah, fair enough. I'm not really sensing that difference as, I must admit, I'm not paying sufficient attention to screen brake lights to make a comparison! At least it's something that should be capable of being tweaked in software so that the deceleration trigger is more appropriate. Perhaps if enough people highlight the issue with Tesla they might review that feature and incorporate a future change.

 

[AllanO]

owever I maintain that when slowing the car at a deceleration similar to what I used to driving an auto BMW e330, the brake lights illuminate.

OK, so you are having a problem with the threshold for switching on the brake lights. You are not having a problem with regen strength. However, the person you agreed with, were complaining about the regen strength.

Anyway, in our Model 3, the brake light will not turn on before the deceleration is stronger than it would have been when engine braking with our previous ICE-car (Mercedes E 220d). In that car, if I wanted more deceleration (without manually downshifting to increase engine braking), I would have to press the brakes - which would also turn on the brake lights. So the threshold seems quite right to me.

 

[M3-Newbie]

None taken , but the reality for me at least is after driving the car for over a year and used one-pedal since the day it was offered it isn't quite right IMHO. The drive itself is lovely, very easy to modulate speed and I don't simply lift off each time I want to slow, I am feathering the power. However I maintain that when slowing the car at a deceleration similar to what I used to driving an auto BMW e330, the brake lights illuminate. So unless I fully engage Driving Miss Daisy mode (future option?), the cars behind see a lot of brake lights from me where previously my smooth driving in an ICE vehicle would not have done this. Therefore upset those behind by constant brake lights or upset those behind by driving so gently I'm failing to make 'normal' progress. I guess the third option is to stop overthinking it, just drive the f*** thing and to hell with worrying about everyone else but that seems a little too much the norm these days, better to be considerate I think

I totally agree - this is my first car with regen (first elec car) and I’m so conditioned to mostly or even fully lift off the accelerator in an ICE to gradually slow for a roundabout/junction etc that I’m very conscious that I (think in my head!) that i look like a boy racer dramatically slamming brakes on for a round about having not been a good driver and read the road.... (I can hear my mother’s commentary in my head as if she was the car behind! Look at this idiot...!) but I have read the road - it just looks different now! the car is going at the same speed and feels fine but I do wonder what others think or how it affects their judgement if the situation - especially on the motorway if I ease off too fast and the brake lights pop on.

I’ve always thought it’s me needing to learn to be lighter on lifting off (if that makes sense?!) but also I think I need to learn to trust the car will break adequately if I leave the lift until later - it’s just years of doing it a different way!
(Or likewise decide not to care!) but I also want to avoid scaring or worrying the driver behind

 

[AllanO]

I’ve always thought it’s me needing to learn to be lighter on lifting off

It is.

I am getting curious now, after reading all these posts. It is obvious that we think differently, but it is not exactly clear to me what is causing this difference. Since you are the first one to actually express your thinking about how you lift the accelerator pedal, I hope you don't mind that I pry into your brain a bit.

First I will describe my own thinking:
Before I test drove a Tesla for the very first time, I knew the concept of one pedal driving, but I had no idea what it would feel like. However, as soon as I tried it, my thoughts were "Okay, this is a function, which can brake the car with the accelerator pedal. So I will need to modulate my lifting of the accelerator pedal in the same way I would modulate my usage of the brake pedal."

And then it immediately became natural to do it that way.

(I had also been worried that this would not work very well with the TACC, when taking over manual control of speed after using TACC. Luckily, it turned out that TACC doesn't disable abruptly like in my other cars - it actually ramps down slowly, so I have plenty of time to catch it with the accelerator pedal and modulate the regen.)

And now back to you:
When reading your post, I get the impression that you think Tesla wants you to drive the car with a lot of regen. So when you lift the foot gradually to control your regen, you feel that you are not trusting the car.

Is this correctly understood? And how have you reached that conclusion?

 

[AndrewGR]

I don’t think there is any difference between the way the car slows down when you disengage TACC and the way it would slow down if you took your foot off the pedal at the same speed.

 

[AllanO]

I don’t think there is any difference between the way the car slows down when you disengage TACC and the way it would slow down if you took your foot off the pedal at the same speed.

Oh, yes, there certainly is.

If I lift the foot, I get instant, full regen.

If I disengage TACC, the regen slowly ramps up over a few seconds.

You can easily test this difference for yourself.

The slow ramp-up of regen makes it very easy to seamlessly take over control with the accelerator pedal without any sudden jumps in regen.