Regenerative braking

[DaveORD]

I've seen several references to the regen braking and using 'low' in slippery conditions. I'm a little confused about this. In slippery conditions, you mainly slide when applying the brakes (or cornering). Regen isn't doing this, just slowing the car using the motor(s), right? So why would you be concerned about slipping if you're not actually braking?

Slowing down via braking or regen is the same when it comes to tires meeting the road and trying to stop. Regen is braking by not using your brake pads and rotors, but by using the motor as a generator. Both have the same effect to apply a force to slow down the wheels. With the brake pedal at least you can modulate and control how much or little to apply the brakes, as everybody who has driven an ICE knows. However when the regen kicks in you have next to no control over that process, it is linked to how much you lift off the accelerator, so lift a little and a little regen kicks in, lift all the way suddenly to react to something and it would be like jamming on your brakes, depending on the battery temp and state of charge. Hopefully it is as good as anti-lock brakes if that ever happens.

Regen works very well when there is great traction between tire and road. When that traction starts to go away, as with standing water or snow or ice, strong regen is not the best choice and it could get you into trouble. That is why we want the low setting for winter time or wet weather so we can coast and apply as much brake as we feel safe doing. Sure we do not get some power back, but in the winter regen may not be worth much anyway if the battery is too cold. I'd give up that little bit of energy return for more control over slowing down when traction may not be ideal. I have almost 40 years experience driving an ICE, and less than 6 months with a BEV and regen. I'd like to stick with something I am comfortable with for the first winter or so, no surprises.

The first thing they teach you to do if you hydro plane is what? Ease off the accelerator and coast to gain back control, do not apply the brakes. Well with strong regen, if you hydro plane and lift off the accelerator, what is going to happen when regen kicks in? It would be like hitting the brakes.

I want that low setting, and I'm glad that my MY is old enough to maintain and have it, so I can switch back and forth depending on road conditions.

 

[pt19713]

So why would you be concerned about slipping if you're not actually braking?

It's more about the weight transfer and overloading the grip on the front wheels. With a smoother transition from accelerator to regen braking, there is less weight transfer on the front wheels and thus more grip. If the weight transfer is abrupt, the tires may lose grip and you lose control.

 

[mrbloons]

Slowing down via braking or regen is the same when it comes to tires meeting the road and trying to stop. Regen is braking by not using your brake pads and rotors, but by using the motor as a generator. Both have the same effect to apply a force to slow down the wheels. With the brake pedal at least you can modulate and control how much or little to apply the brakes, as everybody who has driven an ICE knows. However when the regen kicks in you have next to no control over that process, it is linked to how much you lift off the accelerator, so lift a little and a little regen kicks in, lift all the way suddenly to react to something and it would be like jamming on your brakes, depending on the battery temp and state of charge. Hopefully it is as good as anti-lock brakes if that ever happens.

Regen works very well when there is great traction between tire and road. When that traction starts to go away, as with standing water or snow or ice, strong regen is not the best choice and it could get you into trouble. That is why we want the low setting for winter time or wet weather so we can coast and apply as much brake as we feel safe doing. Sure we do not get some power back, but in the winter regen may not be worth much anyway if the battery is too cold. I'd give up that little bit of energy return for more control over slowing down when traction may not be ideal. I have almost 40 years experience driving an ICE, and less than 6 months with a BEV and regen. I'd like to stick with something I am comfortable with for the first winter or so, no surprises.

The first thing they teach you to do if you hydro plane is what? Ease off the accelerator and coast to gain back control, do not apply the brakes. Well with strong regen, if you hydro plane and lift off the accelerator, what is going to happen when regen kicks in? It would be like hitting the brakes.

I want that low setting, and I'm glad that my MY is old enough to maintain and have it, so I can switch back and forth depending on road conditions.

You’re right on about how regen works compared to brakes, but I’d say you do have full control over the amount of regen applied, albeit using the accelerator pedal as opposed to the brake.
Also I’ve noticed in cold weather the car usually limits the regen anyway if the battery is cold, and from driving the car for 3+ hours at temperatures just above freezing the battery never warms up enough to have full normal regen.
My Model Y does have the low setting option but I’ve never used it, nor do I plan to. I still thinks it’s odd they would remove this feature.

 

[BobDepot]

I have a model y on order and I talked to a Tesla service representative today so I could retest drive a model y with my daughter who gets car sick very easily. I said if she gets car sick on the standard regenerative braking I would have to buy a used model s instead. He told me that a new update is coming that will remove the low setting from all older Tesla models too.

 

[Kodemonkey]

I have a model y on order and I talked to a Tesla service representative today so I could retest drive a model y with my daughter who gets car sick very easily. I said if she gets car sick on the standard regenerative braking I would have to buy a used model s instead. He told me that a new update is coming that will remove the low setting from all older Tesla models too.

Not a bad idea, but once you learn how to modulate the pedal it should be no different than any other car. In our test drive it took some getting used to but after a short time I liked being able to 1 pedal drive. It's just something you have to re-wire in your brain. I have had Toyota Hylander Hybrids and there was always a "hand off" from regen to brakes around 5 MPH. My wife would ocassionally drive it and we would all slam forward in the vehicle because she wasn't used to it. But after a little bit she would get used to it. Sort of like driving a manual. You start to learn where the shift points are cleanest, etc.

 

[Impaler]

It is cold weather related.

I agree and have had the same experience. I was aware that regen was reduced in lower temps, but hadn't experienced it myself, since I got the MY in July. Once the ambient temp got down to about 50F, I started to notice a few regen limits on the regen bar. At times, no matter how far I drove, it wasn't going away. But the other day I pre-heated the car since it was in the 30s and it was gone, fully restored. I noticed the same thing when I set my car with a charge departure time. The cabin was nice and warmed up and so was the battery. So on the first drive of the day, it was good.

 

[hgmichna]

I have a model y on order and I talked to a Tesla service representative today so I could retest drive a model y with my daughter who gets car sick very easily. I said if she gets car sick on the standard regenerative braking I would have to buy a used model s instead. He told me that a new update is coming that will remove the low setting from all older Tesla models too.

What the passenger feels is the same for regenerative braking as for braking with the brake pads. You can create exactly the same physical forces either way. Unless the driver applies different braking styles, the passenger cannot feel any difference between regenerative and active braking.

 

[Impaler]

What the passenger feels is the same for regenerative braking as for braking with the brake pads. You can create exactly the same physical forces either way. Unless the driver applies different braking styles, the passenger cannot feel any difference between regenerative and active braking.

I found that after about a week of driving my Model Y, I have developed a regen single pedal feathering technique that eases the braking and treats it more as a gradual slow down, while still getting the benefits of regen. It just takes a bit of practice. You just have to ease off the accelerator, rather than just take your foot off it entirely.

 

[ftmaybe]

I don't have any experience in extreme cold weather, so I cannot comment on that. But I have never understood the "learning curve" about regenerative braking, nor the need to have settings about regenerative braking (outside of weather concerns). I can only assume that this comes from a driver decision to "decelerate" translating to the rote process of "releasing the accelerator and applying brake".

No matter what car I drive, when I need to start decelerating, I start releasing the accelerator (not immediately apply brake). When the level of deceleration is not adequate, I start applying brake. This is reflexive for me and it works no problem switching between ICE and tesla, because brake application is always for the same reason: brake when deceleration is inadequate. I do not reach for the brake just because I need to slow down. It just ends up that I need to reach for the brake more often in the ICE, and for sure I have occasionally ended up applying brake in the tesla as well, but in either car it is always for the same reason: additional deceleration is required. Maybe this behavior just comes from years and years of driving a manual transmission, many times I did not need the brakes at all because whatever gear I was currently in was short enough to just let that gear wind the car down (also via gradually letting off the accelerator, not simply dumping it).

I also do not understand the "getting sick" with regenerative braking, as 100% of the people I have taken for demonstrations in the Tesla are always shocked when I tell them I have not touched the brakes one time during the drive. These passengers did not "notice" at all when the car was being slowed with regenerative braking. IMO this proves that when managed correctly, there is no difference. You'll only get a difference when you fully release the accelerator and try to apply brake just to slow down, which would be the equivalent of smashing the brake down on an ICE car ... which you also would not do under the majority of driving conditions.

 

[GtiMart]

I suspect that when passengers are getting sick, it's because the driver is behaving with previous reflexes, letting go of the accelerator abruptly as soon as they don't want to accelerate anymore. That makes for a hard deceleration. Typically the driver will then realize they are slowing down too much and give it some "gas" again. It makes for a jerky ride. People that complain that regen makes them lose control of the car on snow/ice probably drive that way too. There should be no harsh user input when driving so you don't upset the car's grip. Releasing the accelerator quickly is a harsh user input.

Retraining one's brain to driving a different thing is what's needed. After that, sure you can prefer more or less regen, but you need to un-learn some reflexes.

EDIT: I now get the inverse effect: when I drive an ICE car I gently let go of the accelerator and am surprised it doesn't slow down more than that, and I scramble for the brake pedal. Habits...

 

[pt19713]

I suspect that when passengers are getting sick, it's because the driver is behaving with previous reflexes, letting go of the accelerator abruptly as soon as they don't want to accelerate anymore. That makes for a hard deceleration. Typically the driver will then realize they are slowing down too much and give it some "gas" again. It makes for a jerky ride. People that complain that regen makes them lose control of the car on snow/ice probably drive that way too. There should be no harsh user input when driving so you don't upset the car's grip. Releasing the accelerator quickly is a harsh user input.

Retraining one's brain to driving a different thing is what's needed. After that, sure you can prefer more or less regen, but you need to un-learn some reflexes.

EDIT: I now get the inverse effect: when I drive an ICE car I gently let go of the accelerator and am surprised it doesn't slow down more than that, and I scramble for the brake pedal. Reflexes...

I've owned manual cars for the last 19 years, so the transition to Tesla Standard braking was easy because it works similar to letting off the throttle with a manual car in a lower gear. Some people just need to learn how to feather off the Tesla accelerator and be smoother. Can't blame people since it's a different way of driving for many people.

 

[BobDepot]

I test drove the model y yesterday brought my daughter to test her car sickness, and it was pretty much the same as my current cars. I have a GTI and a Ford Edge, both automatic, and she gets car sick in those which is why I was concerned about the standard regenerative braking in the first place. One of the replies said they drove a manual before so they made the transition easily. I drove a manual years ago so using that mentality helped a lot. Thank you all for your help.

 

[imola.zhp]

I test drove the model y yesterday brought my daughter to test her car sickness, and it was pretty much the same as my current cars. I have a GTI and a Ford Edge, both automatic, and she gets car sick in those which is why I was concerned about the standard regenerative braking in the first place. One of the replies said they drove a manual before so they made the transition easily. I drove a manual years ago so using that mentality helped a lot. Thank you all for your help.

The more time you spend driving an EV, the better at one-pedal driving you will get. It might be possible that the sickness will be less frequent or go away completely.

 

[Puma2020]

The only issue with driving a Tesla is NOT regen and learning how to control that. That part is easy. The hard part is learning how to not mash the accelerator on takeoff. There is way too much pleasure in the takeoff. I actually find myself slowing down approaching the on ramps just to get a few extra tenths of a second of pleasure. Very enjoyable. Better than sex! Ok, maybe not that, but it's close.

 

[Jimt29]

The standard regen makes me sick. I always use low. I’ll sell my Tesla if they remove the low regen option from existing cars.

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my·op·ic
/ˌmīˈäpik/

adjective

1. • lacking imagination, foresight, or intellectual insight.
     "the government still has a myopic attitude to public spending"
     
     Similar:
     unimaginative
     uncreative
     unadventurous
     narrow-minded
     lacking foresight
     small-minded
     short-term
     narrow
     insular
     parochial
     Definitions from Oxford Languages

 

[Spaghett]

For what it's worth, I initially tried standard regen as well. Girlfriend and I both felt a bit queasy/uneasy after the experiment. So I switched to low and drove that way for about a month a half. Then one day I decided to try standard again. I did a much better job at modulating the accelerator.

Morale of the story, if you have a Model Y (or other Tesla) and have been on low regen since buying it, try doing standard regen now. I think low serves as a good training mode, because even it is a bit more aggressive compared to how a normal ICE vehicle slows down.

 

[Levelheadsteve]

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my·op·ic
/ˌmīˈäpik/

adjective

1. • lacking imagination, foresight, or intellectual insight.
     "the government still has a myopic attitude to public spending"
     
     Similar:
     unimaginative
     uncreative
     unadventurous
     narrow-minded
     lacking foresight
     small-minded
     short-term
     narrow
     insular
     parochial
     Definitions from Oxford Languages

Presumptuous:
overstepping due bounds (as of propriety or courtesy): taking liberties
A person who is presumptuous shows little respect for others by doing things they have no right to do:
It would be presumptuous of me to comment on the matter.

An example of being presumptuous would be for me to presume you are of low intelligence or possibly not successful in life thus causing you to live in a hell hole like Rhode Island or calling someone myopic because they don’t do something the same way you do it. Maybe I should have posted the definition for irony.

 

[drtimhill]

The standard regen makes me sick. I always use low. I’ll sell my Tesla if they remove the low regen option from existing cars.

Perhaps you mean "the way I drive with the standard regen makes me sick" ?

 

[drtimhill]

The key thing for me is preserving the brakes.. I hate having to use them.. but probably unavoidable in the winter months...

Why do you think that? At the end of the day both regen and brakes slow the car by retarding the wheel motion. Unless you reach the point of needing ABS, both should work equally well even in reduced traction. To be sure, the way you apply regen vs brake might make it harder to modulate the braking effect using regen, but I had no trouble all last winter using it. Am I missing something?

 

[Levelheadsteve]

Perhaps you mean "the way I drive with the standard regen makes me sick" ?[

Perhaps the way I drive and the way the Tesla rep I rode with drove and the way a colleague of mine drives his Tesla and the way my friend drives her Tesla with standard regen makes me sick

People with their assumptions. It’s like nobody can have a contrary opinion.