I'm not sure what you mean when you talk about traction control through Regen. Regenerative braking assumes that you have adequate traction to decelerate at something like 0.1 to 0.2 G's. Regen braking is smoother probably than almost any human on friction brakes. That said it's still traction Limited in exceptionally slippery environments. I suspect that it is partially to completely canceled out if it causes wheel spin. But I've never tested this under very slippery conditions. It would make little sense to have regen braking create an unsafe circumstance where wheel spin is generated and the vehicle loses control. So I would have to assume that Tesla has an ABS like algorithm applied to regen braking under these circumstances. But I don't know that for a fact
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1st Snow day for my Model 3 SR+ and for the season - lost control and bumped into divider
- Thread starter Kali
- Start date
I'm not sure what you mean when you talk about traction control through Regen. Regenerative braking assumes that you have adequate traction to decelerate at something like 0.1 to 0.2 G's. Regen braking is smoother probably than almost any human on friction brakes. That said it's still traction Limited in exceptionally slippery environments. I suspect that it is partially to completely canceled out if it causes wheel spin. But I've never tested this under very slippery conditions. It would make little sense to have regen braking create an unsafe circumstance where wheel spin is generated and the vehicle loses control. So I would have to assume that Tesla has an ABS like algorithm applied to regen braking under these circumstances. But I don't know that for a fact
There is no traction control under regen. The car will straight uncontrollably slide. This is why I’ll switch regen to low once we have snow covered roads and leave it there until the roads are clear some time hopefully May’ish
At least in 'Track Mode' it will use power/regen/braking balance when turning into corners going through corners. Similar principle as traction is limited in both cases.
Not disagreeing with you however, quite possibly they haven't done that, but it could be done in theory, just with different parameters.
Don't have much call for snow tyres/performance here locally, so wouldn't know.
However, symmetrical 4WD/AWD DOES help in the snow as it will provide engine braking to all 4 wheels. Had a Subaru before, and that was excellent in the snow, even with non-winter/snow tires.
Yes, that's what I was meaning. IF it limits regen to not lock up it's own wheels, then that could well be more 'reactive' and sensitive than ABS which is a much more mechanical(i.e. slower) system.
Could also apply individual wheel braking to turn (or keep the car straight), a bit like is does in Track Mode.
Not saying it does, but could be an interesting experiment in an empty/snowy parking lot.
Like others have said, you need to have winter tires. It just adds an extra degree of safety. Sounds like you have them, but have not had time to put them on yet. I would not lose confidence in the car over this though, as you really need to see how the car operates with the winters on. I have a rear wheel driver Lexus LS long wheel base that handles poorly in the winter with “all season” tires, but very good to excellent once the winters (Nokian’s) are on. My Model S of course handles better than the Lexus though in the winter and is my primary car at all times.
It's unclear if loss of traction with regen results in anything other than backing off of the motor connected to whichever wheel is slipping.
Via ABS though, each wheel (not each side-to-side pair) can be modulated regarding brake pressure. The result is a theoretically better system for slowing down in low traction siutations. Of course, the "all-wheel braking" for regen only applies to dual motor models, but still only provides front or back motor modulation instead of each wheel.
There is, sort of. Regen will back off under loss of traction. The key is, like ABS, it can only react once you have lost traction. Unlike ABS, regen can be inadvertently fully triggered simply by lifting off the throttle in "scary" situations, leading to slipping where one might not expect to be slipping since this is usually coasting, not braking. If you grew up with a Tesla as the only vehicle you've driven, you may react better. In any case, better to simplify what you need to react to in winter: Use Low regen setting, slow down with the brake pedal, accelerate with the accelerator pedal.
Brake pressure. Can't use regen braking because that doesn't help in the very case you need it, i.e. one side has significantly less traction (there is a single motor that provides power to each side, not a motor per wheel, and this motor is used for regen).
Have you tried it? That is full regen on extremely slick surfaces like wet ice, or very cold ice? I have and it straight slides, old school pre abs uncontrolled slide. Once you breaks the force of friction and start to slide it’s a 4000 lb sled. The only way to regain traction is to hit the breaks to activate ABS or accelerate so the wheels can drive. I only had it happen last winter when I was testing the limits never unexpectedly it’s pretty easy to do when going down hill. I guess if you were really used to the regen you could hold it to an appropriate level with out going too much and brakeing traction. For me I feel like the benefit of full regen is not with the risk of uncontrolled slide going down hill.
I haven't on ice, but very loose gravel (and very recently too). Either there's been a change or we're somehow experiencing different things, though to be fair we are since I'm having us compare gravel to ice which isn't exactly apples to apples.
But agreed, it's better to just limit regen in low traction environments for daily driving.
Gravel is no where close to as slick as clear solid ice at -20F, or rain on ice, or any ice for that matter.
Mind you at that temperature with winters the ice feels more like driving on gravel than compared with driving on ice near freezing temps
That's a fair point. Converting is -30C... yeah, I call that "grippy ice" compared to the normal wet near-freezing deathtrap ice we normally get.
Also very loose gravel on a hard packed surface can be extremely slippery. Again not really comparable to ice, but it's way less traction than most people would expect.
I disagree with this sentiment. I've seen many a time where it was clear that the car was modulating regen in slippery conditions. I wouldn't really want to depend on it to do the job perfectly, but I've intentionally induced regen when it was clear there wasn't anywhere near enough traction for it, and the green bar danced all around as the car adjusted regen but didn't go notably out of control. I guess its possible that the regen was just dropping off as the wheels were stopping and therefore stopped providing power back to the battery, but that wouldn't explain it not going out of control.
That said, if its notably slippery, I wouldn't hesitate to set regen to low for the trip. The risk is too high to save a buck or two on regen.
sorry to hear about your accident ...
you must realize if you have driven for any significant amount of time in a cold climate that most people don't drive correctly in the snow(especially the first snow of the season) ... and Ice is not driving... it is sliding.. and it does not matter 4wd /awd/snow tires... maybe chains would help
you need to slow down period! or better yet if you can help it don't drive in the snow ...you said you were going 40 MPH ... still too fast especially since you indicated icy conditions ... you have to assume there is ice under the snow in that case ... i don't care what tires or vehicle it is recipe for disaster ... it is not a Tesla issue that is for sure
I have a RWD Model S and it handles fine in the snow ... not ice ... and i don't even have snow tires .... i will not drive it if there is any chance of ice ...
even if you think you are a great driver in snow there will be an many fools going way too fast and you may still end up with damage
you must realize if you have driven for any significant amount of time in a cold climate that most people don't drive correctly in the snow(especially the first snow of the season) ... and Ice is not driving... it is sliding.. and it does not matter 4wd /awd/snow tires... maybe chains would help
you need to slow down period! or better yet if you can help it don't drive in the snow ...you said you were going 40 MPH ... still too fast especially since you indicated icy conditions ... you have to assume there is ice under the snow in that case ... i don't care what tires or vehicle it is recipe for disaster ... it is not a Tesla issue that is for sure
I have a RWD Model S and it handles fine in the snow ... not ice ... and i don't even have snow tires .... i will not drive it if there is any chance of ice ...
even if you think you are a great driver in snow there will be an many fools going way too fast and you may still end up with damage
One thing I do, and I might be beaten up for is this.
Keep in mind, If conditions are bad, I'm pretty conservative to begin with.
What I do, when nobody is around me, is a give the brakes a quick light jab. You will know immediately what your traction is, or is not.
If it's bad, I slow down more, if it feels solid, I might go a little faster or continue the speed I was at. I'm testing how much (if at all) the ABS activates. If they active on a light jab, things are pretty bad.
I think this has saved me, many times. You don't want to wait until you are in an uncontrolled situation to find out you we're driving past your traction ability. So I do a mini-test, when it's safe.
There is a risk I could go out of control. That has never come close to happening. But if I didn't do the test now and then, I may be shortly out of control any way. To me it's the only way to assess how much traction you really have. You could be driving on black ice or something and not realize it. Quite often I'll slow down to slower than I was going then test and return back to the speed I was going. I never do that in hydroplaning risk situations. That you just feel and keep a good margin below.
I always run with some the best snows I can get my hands on and AWD etc. but that's not always enough either.
Common sense helps, like why am I driving in this horrible mess to begin with, because 9 times out of 10 it's by choice, but I don't always apply that, I just want to get from point A to point B before time C.
Keep in mind, If conditions are bad, I'm pretty conservative to begin with.
What I do, when nobody is around me, is a give the brakes a quick light jab. You will know immediately what your traction is, or is not.
If it's bad, I slow down more, if it feels solid, I might go a little faster or continue the speed I was at. I'm testing how much (if at all) the ABS activates. If they active on a light jab, things are pretty bad.
I think this has saved me, many times. You don't want to wait until you are in an uncontrolled situation to find out you we're driving past your traction ability. So I do a mini-test, when it's safe.
There is a risk I could go out of control. That has never come close to happening. But if I didn't do the test now and then, I may be shortly out of control any way. To me it's the only way to assess how much traction you really have. You could be driving on black ice or something and not realize it. Quite often I'll slow down to slower than I was going then test and return back to the speed I was going. I never do that in hydroplaning risk situations. That you just feel and keep a good margin below.
I always run with some the best snows I can get my hands on and AWD etc. but that's not always enough either.
Common sense helps, like why am I driving in this horrible mess to begin with, because 9 times out of 10 it's by choice, but I don't always apply that, I just want to get from point A to point B before time C.
How do you know the regen was modulating vs chaotically getting grip, applying regen, losing grip, letting up on regen until it gripped again. I don't I'd consider that controlled modulating
But for the record I never set regen to low all winter. And we get plenty of snow. I never felt it modulate or cause problems. It was AWD with X-Ice snows. But the Model 3 was often in limited regen on its own.
If the wheels could not grip well enough for what regen was available they won't grip well enough to stop when I need to either. So I either slowed down or didn't travel in those conditions. It might be more wise to put regen on low on a RWD.
Took delivery of my LR AWD this Saturday and tried to get my winter tires installed the same day knowing we had two storms coming but everyone had the same idea so couldn't get the tires installed. This morning I had to drop off my daughter to daycare so drove the car for about 6 miles on snow-packed roads while it was still snowing hard. Even with the stock Michelin tires the car felt easily controllable (chill mode and low regen) accelerating, turning and slowing down except for one instance where I was going about 25-30 slight downhill and on quarter throttle. All of a sudden both the rear and front lost traction. It was as if an invisible hand gave the car a counter clockwise push on the passenger door and the car tried to correct it giving it a push clockwise. It only lasted for a about a second and driving in snow for 20 years I just kept the steering wheel straight and my foot on the same throttle position.
Based on my very limited experience with the car, it felt like both the front and rear motors were providing torque to the wheels but at significantly varying rates thus unsettling the car momentarily and then the traction control kicked in to even things out. I am pretty sure it wasn't black ice because the cars in front me followed the same exact path and did not have any issues.
I know this has already been said many time but a dedicated snow mode to lock the front/rear torque split 50/50 would really help the car feel even more secure in slippery conditions. Happy to give up some efficiency for safety...
Based on my very limited experience with the car, it felt like both the front and rear motors were providing torque to the wheels but at significantly varying rates thus unsettling the car momentarily and then the traction control kicked in to even things out. I am pretty sure it wasn't black ice because the cars in front me followed the same exact path and did not have any issues.
I know this has already been said many time but a dedicated snow mode to lock the front/rear torque split 50/50 would really help the car feel even more secure in slippery conditions. Happy to give up some efficiency for safety...
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How do you know the regen was modulating vs chaotically getting grip, applying regen, losing grip, letting up on regen until it gripped again. I don't I'd consider that controlled modulating
But for the record I never set regen to low all winter. And we get plenty of snow. I never felt it modulate or cause problems. It was AWD with X-Ice snows. But the Model 3 was often in limited regen on its own.
I consider the car re-allowing wheels to spin when they stop spinning and start sliding to be modulation. That's how anti-lock brakes work too... I'm not sure how else the car could tell it was approaching the limits of adhesion without noticing a wheel going slower than it was supposed to. I did propose at one point that the Tesla system could potentially be more precise because it has a bunch more cameras than other vehicles, but in a nice snow-white environment, I'd assume that aspect would be useless.
I also almost never go to low regen. Also AWD with X-Ice3 snows.
I also do the experimental will-it-slide test occasionally while driving, and adjust accordingly.
