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Regenerative braking on icy roads
- Thread starter Hahne
- Start date
We live outside of Boulder, Co. It's a 2000' climb to our house from town in about 10 miles. On the way to town (school) It's a steep descent and is icy. We just go slow and if I want to try to make the car turn I have learned I can snap oversteer (slightly) by lifting off the accelerator pedal quickly which gives my 5yo a giggle. On the climb is where it's annoying.... I can't make the car turn unless I induce oversteer by lifting mid corner and force it past where the traction control can recover.. so it is decent work to climb the hill fast. Otherwise it'll push slightly or traction control will just slow us down. Again, going a reasonable speed there are no real concerns. We are on winter tires. I wish it had a track mode.
So, is regen annoying on the descent? not really, just lift (brake) slowly as you would normally if you don't want drama. I think it was mentioned in like the second or third post. If you are understeering you are overdriving your tires in the conditions you are in. Realize that the tires can only provide so much traction whether it be accelerating, turning or stopping.. If you are using all of it to stop it wont turn.
It does get weird when the regen fades after a few moments of driving, it's always strong when we leave the house (cold) but quickly drops off. I will agree it can create a lack of feedback that other cars have when you are left wondering if the car is regenerating and sliding or not regenerating and you need to apply the brakes. I don't like having to clance at the regen bar to make that determination.
I will say it's manageable but not my favorite snow car. Not a huge fan of it's traction control.
look up traction circle on the internet it's what we used to teach our PCA/BMW drivers ed students :
So, is regen annoying on the descent? not really, just lift (brake) slowly as you would normally if you don't want drama. I think it was mentioned in like the second or third post. If you are understeering you are overdriving your tires in the conditions you are in. Realize that the tires can only provide so much traction whether it be accelerating, turning or stopping.. If you are using all of it to stop it wont turn.
It does get weird when the regen fades after a few moments of driving, it's always strong when we leave the house (cold) but quickly drops off. I will agree it can create a lack of feedback that other cars have when you are left wondering if the car is regenerating and sliding or not regenerating and you need to apply the brakes. I don't like having to clance at the regen bar to make that determination.
I will say it's manageable but not my favorite snow car. Not a huge fan of it's traction control.
look up traction circle on the internet it's what we used to teach our PCA/BMW drivers ed students :
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Regen should only fade when the battery is still cold. I see the max regen value go down when I use regen, and back up when I accelerate again, when it's not at its peak. Once the battery has warmed enough this shouldn't happen unless you go down a very big hill I would think... You can use the option that applies friction brakes in that case to keep the feeling consistent.
We have a 2000' descent. It's a big hill.
Maybe that's why it doesn't bother me, it's effectively off. The blended braking option sucks.
Some very limited testing today.while using regen, sliding on ice, I found out that the ABS startet working as soon as I put the foot on the brakepedal. Regen was completly disabled while the brakepedal were in use, and came back as soon as I let go of the brake. The solution may be to use your brakes in an emergency. By the way, the regen did decelerate the car faster than ABS. A weird feeling, to feel loss of braking performace with ABS engaged.
It was a limited test only.
Got the 2022.40.4.2 update today.
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Have you tried the off-road assist mode for climbing up this icy road? It allows more wheel slip and, when I tried it on snow, was easier to induce oversteer.
Have you tried pre-heating the battery? From my experience, this should give you full regen for the whole descent. When I tested this in winter weather on a similar profile of descent (but cleared, salted and dried road), the battery charge gain from regen completely compensated the charge used to pre-heat the battery
The off-road assist on the Model Y is excellent! I was very impressed with the difference it made in snow and ice last Winter. Not only does it balance the power applied to the front and back during acceleration, but it also better balances the regenerative braking front to back to minimize loss of control. Well done Tesla! I think they should call it snow mode.
At what speeds and in what conditions did you use it? Some of the things in the manual would suggest to me it's not intended for driving down a 45 mph snow covered road, although some of it features would be desirable. I would like to see a snow mode that specifically is designed for doing so. Maybe I should be less stingy with using it, however.
- Off-Road Assist is designed to provide overall improvements when driving off-road. In addition to allowing the wheels to spin, Off-Road Assist balances the torque between the front and rear motors to optimize traction. Off-Road Assist improves traction on rough and soft surfaces where one side of the vehicle may lose traction while the other side still has traction. When Off-Road Assist is on, the accelerator pedal provides more gradual torque, which is useful for crawling at low speeds (for example, over rocky surfaces). When enabled, OFF-ROAD displays on the touchscreen above the driving speed.
- Note
Although you can use Slip Start and Off-Road Assist at any speed, it is less effective at higher speeds. - Note
Automatic Emergency Braking and Lane Departure Avoidance do not operate when Off-Road Assist is turned on.
I used it when driving on snow covered local streets and country roads last year, not highways. It is concerning that the manual says traction control is disabled when activated, but from my experience, everything about the traction was better when off-road assist was on.
For fun, I connected Tes-Lax and OBD2 adapter and drove around in ice covered parking lot. It was obvious that the torque applied to the front and back wheels was nearly 50/50 when on, and so was the regen. When the off-road assist was off the acceleration torque was primarily applied to the rear wheels, and the braking regen was primarily applied to the front wheels by comparison (If I remember correctly). Haven't had snow yet this year.
For fun, I connected Tes-Lax and OBD2 adapter and drove around in ice covered parking lot. It was obvious that the torque applied to the front and back wheels was nearly 50/50 when on, and so was the regen. When the off-road assist was off the acceleration torque was primarily applied to the rear wheels, and the braking regen was primarily applied to the front wheels by comparison (If I remember correctly). Haven't had snow yet this year.
Just tried driving around on snowpack in Off-Road Assist up to 40 mph and it felt very surefooted. Not very slippery out (18 degrees F), but it felt good, and it stopped straight when I hit the brakes at 25.
When I tried I let the car choose the duration of preconditioning by using scheduled departure. IIRC it took 20 or 30 minutes and used maybe 4% SOC.
When was the last time? Tesla has updated the battery warming, preconditioning protocol (the Tesla Model Y battery management system currently does not perform nearly as much battery warming as was previously the case.)
Yes, I too am in Spokane and have been driving my new MY in all the snow we just received. Before the MY I had a Subaru Forester and with studded snow tires it was the best winter car I ever had. Before Spokane I lived in Anchorage, Alaska and we drove on ice, snow…you name it….and that Subaru did great. And yes, to the Norwegian chap, dry snow and cold, dry ice can be like driving on dry pavement.
The all season tires that came with the MY do not do well in the snow. I just installed some studded Hakka 10s and they feel great! With the MY I notice that one needs to lift off the accelerator slowly to prevent excessive regeneration causing a skid…..kind of like gently applying the brakes to come to a stop. My wife said she does not like how the MY behaved in icy/snowy conditions and she chooses to drive her Toyota Highlander instead. That’s feels more predictable to her.
Light on the skinny pedal gets you what you need, but not everyone can do that in a panic situation.
buddhafree
2022 MYP
Did you try to change stopping mode from Hold to Roll? In theory it should help to prevent wheels lockup on ice.
Hold, Roll and Creep driving modes are only active at speeds below ~4 MPH. At higher speeds you have to actively control the degree of regenerative braking using your foot (even when regenerative braking may be reduced or if your Tesla Model Y has the option to enable low regenerative braking (2020, early 2021 Model Y only else when equipped the S3XY buttons available from Abstract Ocean.)
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