Tesla removes regenerative braking strength option

[ftmaybe]

Again, it's all a game and how you play. Some people think it is too much work, sometimes it isn't worth it for all kinds of reasons.

I did a "game" for years and years driving my PHEV to try and conserve what little battery I had available to me. However - once my wife got her Tesla and there was plenty of battery available, I started skipping my "game" route when driving to work.

If I take surface streets to work instead of the freeway, in the Tesla I save 20% of the energy. 20 percent is great, of course. However, it takes longer .. and also, the total energy saved is about 1kw. Which costs me only 13 cents. So ..... I could take longer to get to work while stopping repeatedly for stoplights to save 13 cents, or I could just cruise to work on freeway and not worry about the extra 13 cents.

Years of the "game" is a hard habit to break though, I still tend to be as efficient as is reasonable when driving the Tesla. I did experiment with trying to "coast" by fiddling with the accelerator but again, while I did get some much better numbers as far as wh/mile, the economics never made it worth the bother.

 

[derotam]

If the slope of the hill is still speeding you up, you'll soon be dissipating ever higher excess energy to the environment. You have a certain amount of potential energy at the top of the hill. Every bit of your initial potential energy that you lose to the environment is not there to get you up the other side of the hill. Why do you think the heat you generate in the air is different than the heat generated as losses in regen to the battery?

We're talking about the laws of physics here, not of your local jurisdiction. You made an unqualified statement that coasting was always more efficient than regen, but clearly it isn't.

At lower speeds, 10 mph will be a higher ratio of the two speeds, but the energy required for a given distance will be less than a squared relationship to speed, but still greater than linear.

For a given decline there is X amount of potential energy for a given object(car) right?

If I go down that hill and I regen to maintain a certain speed limit, I capture a PORTION of that potential energy. I do not capture all of it if I still have my foot on the accelerator while in regen.

If I coast down that same hill and I continue to speed up until just before the bottom of the hill I stop speeding up because of drag forces, then I have captured ALL of the potential energy for the given object.

And just to clarify if I hadn't all ready and was mentioned by holmgang... I am only saying that coasting is always better than regen if there is not a stop at the bottom of the hill or I do not have to use the brakes at all.

 

[ftmaybe]

My wife's model 3 was totaled a few months ago, she just picked up her replacement SR+ at the end of Sep. I checked it last night and it does have the regen selector option under the driving menu.

 

[tomas]

I can say with scientific certainty that this thread has skidded off the road due to the elimination of low regeneration option.

 

[TIppy]

For a given decline there is X amount of potential energy for a given object(car) right?

If I go down that hill and I regen to maintain a certain speed limit, I capture a PORTION of that potential energy. I do not capture all of it if I still have my foot on the accelerator while in regen.

If I coast down that same hill and I continue to speed up until just before the bottom of the hill I stop speeding up because of drag forces, then I have captured ALL of the potential energy for the given object.

And just to clarify if I hadn't all ready and was mentioned by holmgang... I am only saying that coasting is always better than regen if there is not a stop at the bottom of the hill or I do not have to use the brakes at all.

This is not correct. You have not captured all the potential energy just because gravitational and drag forces balance. That just means you have stop accelerating. The car requires a given amount of power to go a given speed. When you are coasting down the hill, this power comes from the weight of the car times it speed in the vertical direction. Power is force time velocity. The slope of the hill determines the speed where drag and gravity forces balance. A four percent grade is about 70 mph.

The amount of energy you dissipate going down the hill is the force on the car times the distance. The force on the car goes up as the speed increases, so the energy used to get to the bottom of the hill increases. This energy comes from the only source which is the initial potential energy. Your only source of energy to get back up the hill is the kinetic energy at the bottom of the hill. This will be less than the sum of the kinetic energy plus the energy captured in the battery for the car that used regen at a lower speed.

 

[derotam]

Potential energy is based on ALL factors of a given scenario. MASS of an object, air density, temperature of the road, force of gravity based on where you are on the planet, etc etc etc. If I have two identical cars at the top of a given slope, the potential energy of getting those two cars to the bottom of the hill is the SAME. If you coast all the way down you convert all the energy into kenitic energy. If you use regen, you convert PART(because of regen heating and other losses) of the energy into energy into the battery.

 

[MorrisonHiker]

It would nice to be able to switch from no, low, and standard while driving via the scroll wheel.

Copy your driver profile to a new Snow/Ice profile and under the new profile, set Regen to Low and consider setting Chill mode as well. You can then toggle profiles while driving. It's a couple taps on the screen but easier than going through all the menus to try to make changes while driving.

 

[SimpleJack1]

I set mine to low the very first 10 feet, when I first drove my car off the lot. Hate it

 

[TIppy]

Potential energy is based on ALL factors of a given scenario. MASS of an object, air density, temperature of the road, force of gravity based on where you are on the planet, etc etc etc. If I have two identical cars at the top of a given slope, the potential energy of getting those two cars to the bottom of the hill is the SAME. If you coast all the way down you convert all the energy into kenitic energy. If you use regen, you convert PART(because of regen heating and other losses) of the energy into energy into the battery.

Change in potential energy is mass times the acceleration due to gravity times the change in height. It doesn't have anything to do with those other things you mention.

This is a simple problem in energy balance. Going faster wastes more of your original potential energy, so your change in height going up the other side will be less (potential energy).

 

[derotam]

Change in potential energy is mass times the acceleration due to gravity times the change in height. It doesn't have anything to do with those other things you mention.

This is a simple problem in energy balance. Going faster wastes more of your original potential energy, so your change in height going up the other side will be less (potential energy).

So how does "Going faster wastes more of your original potential energy" if you don't account for the "other things you mention".

If I put a brick wall in your path does your potential energy at the bottom not change?

 

[TIppy]

So how does "Going faster wastes more of your original potential energy" if you don't account for the "other things you mention".

I do account for them. They are the drag terms, which have nothing to do with how much energy you start with(potential energy). If you decide to tow your boat behind your ice suv, that doesn't change the amount of gas in your tank. The drag of your boat causes your suv to use more fuel per hour, so your range will be less. The potential energy is what you have to play with (based solely on the difference in height), and the drag terms are what use up some of that energy but don't contribute to making you go higher on the uphill side.

 

[derotam]

I do account for them. They are the drag terms, which have nothing to do with how much energy you start with(potential energy). If you decide to tow your boat behind your ice suv, that doesn't change the amount of gas in your tank. The drag of your boat causes your suv to use more fuel per hour, so your range will be less. The potential energy is what you have to play with (based solely on the difference in height), and the drag terms are what use up some of that energy but don't contribute to making you go higher on the uphill side.

Great!, so back to coasting down a hill... You keep saying that going faster(while coasting) WASTES more of the potential energy, but you are not looking at how much energy is being shifted into kinetic energy, vs how much energy is added to the battery in regen.

 

[TIppy]

Great!, so back to coasting down a hill... You keep saying that going faster(while coasting) WASTES more of the potential energy, but you are not looking at how much energy is being shifted into kinetic energy, vs how much energy is added to the battery in regen.

I don't have to partition the energy in any particular way. You start with a certain amount of potential energy. Along the way some of it is removed. What's left over at the bottom of the hill will change your height on the uphill side. The more of the original energy you have at the bottom, the higher you'll go.

 

[drtimhill]

I really think the car needs a "Snow Mode" anyway .. adjust regen, traction control, reduce motor power etc. I have an approx equivalent using a driver profile, but a true snow mode could do much more.

 

[GtiMart]

I've seen a few people suggesting that low regen is better in winter. I've driven one full Quebec winter with normal regen and have found the regen and stability/traction system to be great. I'm happy to see some other people agree with me.

Now, one person here has put a finger on something: if you remove your foot from the accelerator abruptly to go to the brake, it might slip for a fraction of a second. Sure, anytime you do something abrupt, the stability system will need a little moment to compensate. Letting go of the accelerator quickly is equivalent to pushing brakes hard in an EV. Try hitting the brakes hard and see how much time it takes before ABS recovers. It's the same for the regen and traction control. It is great but don't purposefully do any harsh maneuvers in winter.

With that said, with proper winter driving, and proper tires, I (and others) have found the regen system in the Tesla Model 3 to be very capable, similar to ABS. It is not necessarily true of other EVs. Some will plain cut regen when they sense slippage, and that is an extremely bad feeling when you drive.

I find the same to be true for motor power. I for one don't want to use chill mode in winter... why would I cut myself from potential power. I can modulate power with my right foot, and the traction control does a great job if I'm not careful. In fact it even limits too much IMO, but I recognize that is subjective.

 

[tomas]

I've seen a few people suggesting that low regen is better in winter. I've driven one full Quebec winter with normal regen and have found the regen and stability/traction system to be great. I'm happy to see some other people agree with me.

Now, one person here has put a finger on something: if you remove your foot from the accelerator abruptly to go to the brake, it might slip for a fraction of a second. Sure, anytime you do something abrupt, the stability system will need a little moment to compensate. Letting go of the accelerator quickly is equivalent to pushing brakes hard in an EV. Try hitting the brakes hard and see how much time it takes before ABS recovers. It's the same for the regen and traction control. It is great but don't purposefully do any harsh maneuvers in winter.

With that said, with proper winter driving, and proper tires, I (and others) have found the regen system in the Tesla Model 3 to be very capable, similar to ABS. It is not necessarily true of other EVs. Some will plain cut regen when they sense slippage, and that is an extremely bad feeling when you drive.

I find the same to be true for motor power. I for one don't want to use chill mode in winter... why would I cut myself from potential power. I can modulate power with my right foot, and the traction control does a great job if I'm not careful. In fact it even limits too much IMO, but I recognize that is subjective.

TOTALLY agree. 8 years of winter Tesla driving on “normal”.

 

[JulienW]

Maybe Tesla's new FSD 4-D code has ice/wet/snowy/cold weather accounted for and will automatically adjust regen. Of course if it is as good as Tesla's "Deep Rain" windshield wipers........

 

[BR666T]

I've seen a few people suggesting that low regen is better in winter. I've driven one full Quebec winter with normal regen and have found the regen and stability/traction system to be great. I'm happy to see some other people agree with me.

Now, one person here has put a finger on something: if you remove your foot from the accelerator abruptly to go to the brake, it might slip for a fraction of a second. Sure, anytime you do something abrupt, the stability system will need a little moment to compensate. Letting go of the accelerator quickly is equivalent to pushing brakes hard in an EV. Try hitting the brakes hard and see how much time it takes before ABS recovers. It's the same for the regen and traction control. It is great but don't purposefully do any harsh maneuvers in winter.

With that said, with proper winter driving, and proper tires, I (and others) have found the regen system in the Tesla Model 3 to be very capable, similar to ABS. It is not necessarily true of other EVs. Some will plain cut regen when they sense slippage, and that is an extremely bad feeling when you drive.

I find the same to be true for motor power. I for one don't want to use chill mode in winter... why would I cut myself from potential power. I can modulate power with my right foot, and the traction control does a great job if I'm not careful. In fact it even limits too much IMO, but I recognize that is subjective.

I don't think full regen is safe in very slippery conditions because throttle lift-off it is more difficult to modulate than braking in my experience. And I use "normal" regen 100% of the time in non-slippery conditions so I am very familiar with it.

Ultimately, I want to be able to lift my foot off the pedals and have forward acceleration go as close to zero as possible IMMEDIATELY.

 

[bruce4000]

So how does "Going faster wastes more of your original potential energy" if you don't account for the "other things you mention".

If I put a brick wall in your path does your potential energy at the bottom not change?

If you put a wall in the way, you won’t get to the bottom but you will convert your kinetic energy into deforming the structure of your car and heat! Starting to remind me of physics class in college. I think a snow mode be good.

 

[GZDongles]

I've seen a few people suggesting that low regen is better in winter. I've driven one full Quebec winter with normal regen and have found the regen and stability/traction system to be great. I'm happy to see some other people agree with me.

Now, one person here has put a finger on something: if you remove your foot from the accelerator abruptly to go to the brake, it might slip for a fraction of a second. Sure, anytime you do something abrupt, the stability system will need a little moment to compensate. Letting go of the accelerator quickly is equivalent to pushing brakes hard in an EV. Try hitting the brakes hard and see how much time it takes before ABS recovers. It's the same for the regen and traction control. It is great but don't purposefully do any harsh maneuvers in winter.

With that said, with proper winter driving, and proper tires, I (and others) have found the regen system in the Tesla Model 3 to be very capable, similar to ABS. It is not necessarily true of other EVs. Some will plain cut regen when they sense slippage, and that is an extremely bad feeling when you drive.

I find the same to be true for motor power. I for one don't want to use chill mode in winter... why would I cut myself from potential power. I can modulate power with my right foot, and the traction control does a great job if I'm not careful. In fact it even limits too much IMO, but I recognize that is subjective.

Thank you for sharing your experience. It's my first winter with a Model 3 LR AWD in Michigan. Our winters are cold, but only moderately snowy in Southeast Michigan.

Just to confirm that I understand how the car reacts with regen, will the stability/traction control activate with regen on but no braking? Your post seems to indicate that it will activate but there would be a slight delay if you lift off the pedal abruptly. However, the car would not lock the wheels and go into a continuous slide if you lifted your foot off the pedal but didn't push the brakes, correct?