Regen on ice?

[milleron]

In the comments of a Transport Evolved YouTube video, one viewer mentioned that his experience driving some sort of utility device with a "retarder" leads him to believe that regenerative braking could put an EV into a skid or spin if it engages on ice. I am skeptical because i don't believe that regen can lock wheels, but I'm wondering if anyone ever experienced loss of control in such a situation OR if any testing organization or manufacturer has ever published any experimental results.

 

[ewoodrick]

I highly suspect that traction/ABS control is going to take over and control the car.

 

[ckoval7]

I think the general advice is to set regen to low for icy conditions. Of course if you just keep your cool and control your foot on the go pedal, you should be able to keep yourself from going into a skid. If you're about to hit something and you have ice under your tires, there's probably nothing you can do anyway.

 

[Graffi]

I live in San Diego so Ice is NEVER a problem, and my trips are always in warmer weather.

However I have read here on this forum that Regen should be set to lowest level when driving in Ice and Snow. Maybe in Owners manual, so check there.

 

[Jhelin]

There is some sort of Anti Locking system on the regen as per Regen braking in slippery situations

 

[Barry]

I think the general advice is to set regen to low for icy conditions.

Absolutely. I've been through 3 Colorado winters with the MS. Whenever the roads are icy/snowy, I set regen to low.

It's not necessary for the wheels to lock up to skid. The wheels decelerating faster than the reduced friction surface can handle is enough.

 

[Babaron]

Count me as another who always sets regen to low when road conditions are slick. I believe it gives the driver more feel and control of tire traction or loss thereof.

 

[coleAK]

I originally posted this on the model 3 but think it applies as I can’t imagine the traction control can be all that difference, may be worse in the S since it is heavier.

winter started my way 8 days ago and my thoughts so far on winter with the 3. Since Sunday it has been below freezing down to 8F and roads of fresh snow, packed snow, and straight clear ice with little contact with the asphalt. I have AWD LR 3 and am running Nokian Hakkapeleta 9’s.

I turned regenerative breaking to low and think I’ll keep it that way all winter. The reason is even with the best winter tires (Hakka 9) going down hill when regen kicks in it isn’t controlled like ABS and the traction control seems confused. I could tell you will straight slide and without winter tires it would be highly uncontrollable. Also “chill” mode is my friend. It acts similar to a 2nd gear start and limits torque that is the enemy on winter roads

As for the tires. I’m a huge Nokian fan, I would never put another brand of winter tires on a vehicle. They are the safest and longest lasting. I’ve had Hakka 3,4,5,7 and now 9. The 9 is amazingly quiet although I will admit they were only on dry roads for 1 day. They have much less “stud tap” at low speeds than any other studded tire I have had before.

Overall so far I put the Tesla similar to the three best winter cars we have owned over the years: Subaru Legacy (which I think is also the winter driving gold standard) Audi allroad (a6 version), and Mercedes e 4Matic.

 

[cdeleo]

I kind of wish there was an off mode for regen. I just got my M3 and I'm concerned mainly with a situation that I have found myself in more than a few times in the past. Which is a black ice covered bridge on the expressway. I've pretty much have trained myself over the years with gas vehicles to let off on the gas and coast over the bridge if any possibility of ice. I have felt the wheels unlock from the road at times even doing this. Some times there is just nothing you can do but I feel that even on low regen this situation will occur more often. I'm partly tempted to try and get myself into the habit of maintaining speed with no acceleration or regen. But I think this will be hard and also I have a deeply ingrained habit of letting off the "gas"

 

[Seawind300]

Living in Newfoundland I see my fair share of ice and snow. Last winter and the start of this one, I leave the regen on "standard". I find it predictable and easy to control. I'm sure there are circumstances that the regen may not be the best option but as of yet, it has worked very well for my driving style.

Mike

 

[skitown]

Living in Newfoundland I see my fair share of ice and snow. Last winter and the start of this one, I leave the regen on "standard". I find it predictable and easy to control. I'm sure there are circumstances that the regen may not be the best option but as of yet, it has worked very well for my driving style.

Mike

I love Standard Regeneration on slick roads too - both with RWD and AWD Teslas. Reminds me of downshifting with manual transmissions and using engine compression vs. brakes in my old Subarus when driving to and from the ski hill. I don't personally understand the issue people have. Sure, if I panic and pull my foot off the accelerator that's no good, but it's no different than panicking on Low Regen or in an ICE car and hitting the brakes. Don't Panic! Panicking on slick roads is a recipe for disaster in general. With Standard Regeneration, my foot never needs to leave the accelerator - I can just feather carefully under almost any situation to decelerate. When set to Low Regeneration, I would be more likely to have to remove my foot from the accelerator and use the brake. IMO, this transition from accelerator to brake is where the real problems can arise quickly on slick roads. And even if that doesn't cause a problem, I'm forced to still feather the brake just as carefully. Far easier to just keep my foot glued to the accelerator.

 

[Seawind300]

I love Standard Regeneration on slick roads too - both with RWD and AWD Teslas. Reminds me of downshifting with manual transmissions and using engine compression vs. brakes in my old Subarus when driving to and from the ski hill. I don't personally understand the issue people have. Sure, if I panic and pull my foot off the accelerator that's no good, but it's no different than panicking on Low Regen or in an ICE car and hitting the brakes. Don't Panic! Panicking on slick roads is a recipe for disaster in general. With Standard Regeneration, my foot never needs to leave the accelerator - I can just feather carefully under almost any situation to decelerate. When set to Low Regeneration, I would be more likely to have to remove my foot from the accelerator and use the brake. IMO, this transition from accelerator to brake is where the real problems can arise quickly on slick roads. And even if that doesn't cause a problem, I'm forced to still feather the brake just as carefully. Far easier to just keep my foot glued to the accelerator.

Exactly

 

[cdeleo]

Maybe I'm over reacting. I went out this evening and found a safe place to play around with the car and see how it handled in a slide. With snow it seems to handle very well, even with the all season tires. I haven't experienced any wind blown iced over road yet and hard to find safe places with that kind of condition to get a feel for it. Maybe tomorrow I can find a place supposed to get to a low of 7F

 

[coleAK]

I love Standard Regeneration on slick roads too - both with RWD and AWD Teslas. Reminds me of downshifting with manual transmissions and using engine compression vs. brakes in my old Subarus when driving to and from the ski hill. I don't personally understand the issue people have. Sure, if I panic and pull my foot off the accelerator that's no good, but it's no different than panicking on Low Regen or in an ICE car and hitting the brakes. Don't Panic! Panicking on slick roads is a recipe for disaster in general. With Standard Regeneration, my foot never needs to leave the accelerator - I can just feather carefully under almost any situation to decelerate. When set to Low Regeneration, I would be more likely to have to remove my foot from the accelerator and use the brake. IMO, this transition from accelerator to brake is where the real problems can arise quickly on slick roads. And even if that doesn't cause a problem, I'm forced to still feather the brake just as carefully. Far easier to just keep my foot glued to the accelerator.

That is the way I feel going downhill from my house with low Regen. The hill I go up and down every day is ~1000 vertical feet over 4 miles and going down it in low Regen is about the same as riding down it in 3rd gear in my truck. We’ve had pretty insane ice in Anchorage over the last 2 weeks though much more ice than snow. I guess it’s personal preference normal to me slows it down way too much unless I’m trying to crawl at 10-15 mph.

 

[OlderThanDirt]

Depends how you “feel” your car with your back side.

I much prefer the standard regen setting. To me if you’re going to fast for conditions it doesn’t matter if you’re using regen braking or standard brakes.

The reality is that there’s a good chance regen braking may be limited by cold conditions anyway. So why switch to the low setting?

But then it’s back to personal feel.

 

[skitown]

That is the way I feel going downhill from my house with low Regen. The hill I go up and down every day is ~1000 vertical feet over 4 miles and going down it in low Regen is about the same as riding down it in 3rd gear in my truck. We’ve had pretty insane ice in Anchorage over the last 2 weeks though much more ice than snow. I guess it’s personal preference normal to me slows it down way too much unless I’m trying to crawl at 10-15 mph.

I'm all for personal choice, so you'll get no argument from me on your preference. Whatever makes people feel comfortable, to each their own, and you obviously drive in a lot of snow and ice. I'm curious though what you are doing with your right foot when you experience this: "normal to me slows it down way too much". Are you removing it completely from the accelerator? I would totally agree if that's the case. Or are you saying that even when you feather it, you feel like it slows you down too much? I would guess it's the latter, but just haven't experienced that. Just like when I'm driving on the interstate on dry roads, I feather the accelerator ever so slightly to mimic coasting in an ICE. The first road trip home with the Tesla I learned fast that I'd spent my whole driving career coasting it seemed! LOL. That habit ended quickly.

 

[cdeleo]

I'm not sure how my habits are going to adapt. I have an ICE truck and the new M3. I guess time will tell

 

[skitown]

I'm not sure how my habits are going to adapt. I have an ICE truck and the new M3. I guess time will tell

Every time I drive an ICE car now I feel like I'm in a horse and buggy just trying to hang on for dear life.

 

[coleAK]

I'm all for personal choice, so you'll get no argument from me on your preference. Whatever makes people feel comfortable, to each their own, and you obviously drive in a lot of snow and ice. I'm curious though what you are doing with your right foot when you experience this: "normal to me slows it down way too much". Are you removing it completely from the accelerator? I would totally agree if that's the case. Or are you saying that even when you feather it, you feel like it slows you down too much? I would guess it's the latter, but just haven't experienced that. Just like when I'm driving on the interstate on dry roads, I feather the accelerator ever so slightly to mimic coasting in an ICE. The first road trip home with the Tesla I learned fast that I'd spent my whole driving career coasting it seemed! LOL. That habit ended quickly.

We’ve only had the Tesla a little over a month so still getting used to it. Going down the hill with Regen low I don’t touch either pedals much. Feather the accelerator a little when needed but for the most part just ride the Regen break all the way down and it holds me at a nice controlled ~40 mph. If I do the same trip in regular I have to feather a lot more and feel like I just can’t get the speed correct, but that could just be the learning curve.

 

[OlderThanDirt]

We’ve only had the Tesla a little over a month so still getting used to it. Going down the hill with Regen low I don’t touch either pedals much. Feather the accelerator a little when needed but for the most part just ride the Regen break all the way down and it holds me at a nice controlled ~40 mph. If I do the same trip in regular I have to feather a lot more and feel like I just can’t get the speed correct, but that could just be the learning curve.

While I can't speak to a rear wheel drive Tesla I can on the dual motor. Feathering the accelerator (keeping the power slightly on) works exceptionally well for me. Especially on sharp turns like roundabouts the car tracks very well. Just keep easing into it and I'm thinking you will get the feel. We live in the Lake Michigan lake effect snow belt so snow covered and icy roads tend to be a daily occurrence once the cold settles in.