No, I'm not showing a picture of my car ditched after hitting black ice patch on highway. Because I kept it on the road. Luckily.
Your natural reaction when sensing loss of traction on ice is to lift the accelerator pedal.
Regen kicks in when you do that. Doesn't matter if set to high or low regen, the car dips into the green zone.
(I set my regen to low for highway driving).
Regen is like hitting the brakes, but only in the rear (I have S85 not a D).
Braking in the rear on black ice is ... nerve wracking.
It creates drag and induces slippage in the rear and the car starts to sway in the rear, and loud CHUNK CHUNK sounds kick out from the rear as ESC and/or other mechanisms of the car back there are realizing the loss of traction and try to lessen the grip of regen.
And you continue swaying and concentrate on steering the car to keep it on a line.
When you get it under control, it's time to go clean your pants.
OK, this would happen on D model too, maybe all four corners start regen and slipping and sway front and rear... Maybe you get smarter "torque balanced" regen and only one end or the other start slipping, and swap slipping duty as front and rear fight for regen duty. Good luck with that! One axle was enough for me.
Q: What the hell would happen if you were auto-piloting your car and this happened... what would the software do? Well, you shouldn't be using auto-pilot in adverse weather conditions anyway... not even cruise control. Driver beware, your fault.
Cause of my incident: SUDDEN shift of driving dynamic and brake drag created by regen, even set to LOW. On sudden appearance of almost frictionless ice surface on road. Surprise!
I could do two things, if I had all my mental faculties working and great reaction time, I could try to NOT LIFT the pedal completely but match speed to energy to be flat-line neutral (not orange not green but flat)... i.e. no torque difference between road and wheel rotation. Good luck with this on patchy ice. NO human could keep this matched using the pedal.
Or, I could bump the gear selector from D up to N. And coast, and keep off the brakes. I chose this approach, and practiced it on non-ice portions getting ready for the next surprise. But if you bump from D up too hard (double bump) car thinks you are asking for R... and beep-beep warning no way can you do that... and keeps you in D doesn't even go half-way and give you N. You must lightly tap up to get N.
Easy to do in panic situation, right? Lightly tap up to N... so your rear end doesn't lose it completely and come around the other way. Tap too hard and .. you lose. You get about one shot at this before its too late. And you have to drive with your finger tip on the gear selector, in ready to tap position. Easy to do miles on end.
I suggest you practice. It's the only thing you can do.
Until Tesla improves this driving dynamic in software.
What should Tesla do? TWO THINGS immediately for next software release please:
1. At least offer a USER CONTROL slider for REGEN selection: OFF. Zero, none, coast when foot off pedal.
Maybe tie the feature to "Cold whether package" for those of us who face icy roads on a pretty regular basis.
What else could they do?
2. When the car is in motion, consider a user input double bump from D to R on the gear lever as a request for N. And put the car in N. Just do it.
Having the car do a NO CHOICE braking maneuver special on sudden loss of traction surface.... is silly. :scared:
Your natural reaction when sensing loss of traction on ice is to lift the accelerator pedal.
Regen kicks in when you do that. Doesn't matter if set to high or low regen, the car dips into the green zone.
(I set my regen to low for highway driving).
Regen is like hitting the brakes, but only in the rear (I have S85 not a D).
Braking in the rear on black ice is ... nerve wracking.
It creates drag and induces slippage in the rear and the car starts to sway in the rear, and loud CHUNK CHUNK sounds kick out from the rear as ESC and/or other mechanisms of the car back there are realizing the loss of traction and try to lessen the grip of regen.
And you continue swaying and concentrate on steering the car to keep it on a line.
When you get it under control, it's time to go clean your pants.
OK, this would happen on D model too, maybe all four corners start regen and slipping and sway front and rear... Maybe you get smarter "torque balanced" regen and only one end or the other start slipping, and swap slipping duty as front and rear fight for regen duty. Good luck with that! One axle was enough for me.
Q: What the hell would happen if you were auto-piloting your car and this happened... what would the software do? Well, you shouldn't be using auto-pilot in adverse weather conditions anyway... not even cruise control. Driver beware, your fault.
Cause of my incident: SUDDEN shift of driving dynamic and brake drag created by regen, even set to LOW. On sudden appearance of almost frictionless ice surface on road. Surprise!
I could do two things, if I had all my mental faculties working and great reaction time, I could try to NOT LIFT the pedal completely but match speed to energy to be flat-line neutral (not orange not green but flat)... i.e. no torque difference between road and wheel rotation. Good luck with this on patchy ice. NO human could keep this matched using the pedal.
Or, I could bump the gear selector from D up to N. And coast, and keep off the brakes. I chose this approach, and practiced it on non-ice portions getting ready for the next surprise. But if you bump from D up too hard (double bump) car thinks you are asking for R... and beep-beep warning no way can you do that... and keeps you in D doesn't even go half-way and give you N. You must lightly tap up to get N.
Easy to do in panic situation, right? Lightly tap up to N... so your rear end doesn't lose it completely and come around the other way. Tap too hard and .. you lose. You get about one shot at this before its too late. And you have to drive with your finger tip on the gear selector, in ready to tap position. Easy to do miles on end.
I suggest you practice. It's the only thing you can do.
Until Tesla improves this driving dynamic in software.
What should Tesla do? TWO THINGS immediately for next software release please:
1. At least offer a USER CONTROL slider for REGEN selection: OFF. Zero, none, coast when foot off pedal.
Maybe tie the feature to "Cold whether package" for those of us who face icy roads on a pretty regular basis.
What else could they do?
2. When the car is in motion, consider a user input double bump from D to R on the gear lever as a request for N. And put the car in N. Just do it.
Having the car do a NO CHOICE braking maneuver special on sudden loss of traction surface.... is silly. :scared:
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