Any brake pedal blending for more regen?

  • SUPPORT THE SITE AND ENJOY A PREMIUM EXPERIENCE!
    Welcome to Tesla Owners Online, four years young! For a low subscription fee, you will receive access to an ad-free version of TOO. We now offer yearly memberships! You can subscribe via this direct link:
    https://teslaownersonline.com/account/upgrades

    SUBSCRIBE TO OUR YOUTUBE CHANNEL!
    Did you know we have a YouTube channel that's all about Tesla? Lots of Tesla information, fun, vlogs, product reviews, and a weekly Tesla Owners Online Podcast as well!

Dogwhistle

Top-Contributor
Joined
Jul 2, 2017
Messages
461
Location
Delaware
Tesla Owner
Model 3
Country
Country
#1
I have a question concerning about Model 3 braking behavior in Low vs Standard. I understand that accelerator lift-off regen is signficantly reduced in the LOW setting compared to standard, so as to replicate ICE coasting behavior. Is the remaining amount of standard regen just permanently lost, or is it now available through “blending” in the brake pedal?

For instance, in most hybrids, you lift off the accelerator and get a “low” amount of regen, as shown by the small deflection in the “charge” graph as you see on a Prius. Then, when you start to press the brake pedal, you can see the the “charge” line increase until its full, at which point the friction brakes start adding their input as you increase pressure on the brake pedal. This is “blended” brake behavior.

With the Model 3, is there any blending at all when in the LOW setting? Can I still use the full amount of theoretically availble regen when using LOW? Or does Tesla totally separate regen from friction braking, and LOW is just LOW, and the brake pedal only operates the friction brakes exclusively?

I would think an easy way to test this is to put the car in LOW regen, then see if the power meter increases in the regen direction (moves left) as you start to apply some light brake pressure. I’m sure someone has tried this and knows the answer!

I could see myself using LOW more often if I could still tap the full regen capability with the brake pedal through blending. But if that extra regen is just completely lost in LOW, then STANDARD it is!

Thx
 

Bokonon

Self-identified Teslaholic
Moderator
TOO Supporting Member
Joined
Apr 12, 2017
Messages
3,174
Location
Boston
Tesla Owner
Model 3
Country
Country
#4
Got it. It would be nice if they did, but I can see how they prefer to keep it simple. Standard it is!
I kinda wish the brake pedal were blended too (or that it were an option), not because I prefer it, but because it's a lot more intuitive to drivers who are migrating from an ICE, or who aren't the primary Tesla driver in the household and usually drive an ICE. It takes practice to undo decades of using a dedicated brake pedal to slow down, and switching back and forth between an ICE doesn't really help with making that adjustment.
 

Dogwhistle

Top-Contributor
Joined
Jul 2, 2017
Messages
461
Location
Delaware
Tesla Owner
Model 3
Country
Country
#6
As a driver of a blended-brake car for the past 6 years, I'm looking forward to NOT having the brake pedal control regen. It's very disconcerting when you're braking and the car decides to suddenly remove all regen, and feels like it suddenly lunges forward.
Well, that’s not behavior exclusive to blended brake systems. My BMW i3 cuts out regen fairly often when it hits a bump or something. It’s a known characteristic of the system, supposedly related to the fact that all the regen is coming from the rear wheels, which can cause instability in certain situations. I’m surprised Tesla doesn’t have something similar.
 

BigBri

Top-Contributor
Joined
Jul 16, 2016
Messages
1,083
Location
Toronto, Ontario
Tesla Owner
Model 3
Country
Country
#8
As a driver of a blended-brake car for the past 6 years, I'm looking forward to NOT having the brake pedal control regen. It's very disconcerting when you're braking and the car decides to suddenly remove all regen, and feels like it suddenly lunges forward.
Agree 1000%. My only complaint about the Leaf is the breaking. I don't mind the vibration sensation at all but the sense when it 'sticks' and lunges forward is awful.
 

Bokonon

Self-identified Teslaholic
Moderator
TOO Supporting Member
Joined
Apr 12, 2017
Messages
3,174
Location
Boston
Tesla Owner
Model 3
Country
Country
#10
As a driver of a blended-brake car for the past 6 years, I'm looking forward to NOT having the brake pedal control regen. It's very disconcerting when you're braking and the car decides to suddenly remove all regen, and feels like it suddenly lunges forward.
Agreed, I found this behavior alarming (not to mention dangerous) with my first-generation Volt, as it usually happened on snow-covered roads or just after hitting a pothole while braking.

The e-Golf seems to handle it differently, though, more inline with how I'd expect it to work: when regen becomes temporarily unavailable, it seems to apply the friction brakes just enough to achieve the expected braking force for the current level of pedal displacement, just as it does when regen is unavailable due to temperature or full charge. Maybe I don't have enough appreciation for the complexity of blended braking systems, traction control, and the pertinent mechanics, but from an end-user perspective, I wouldn't expect it to work any other way.
 

jsmay311

Top-Contributor
Joined
Oct 2, 2017
Messages
411
Location
Chicago Suburbs
Country
Country
#12
As a driver of a blended-brake car for the past 6 years, I'm looking forward to NOT having the brake pedal control regen. It's very disconcerting when you're braking and the car decides to suddenly remove all regen, and feels like it suddenly lunges forward.
So what do Tesla vehicles do (particularly RWD Teslas) when they detect wheel slip during regen?

Do they not cut out regen altogether like some other EVs do? If not, how do they regain traction?
 

Mad Hungarian

Resident TOO Wheel/Tire Guru
Joined
May 20, 2016
Messages
1,073
Location
Montreal, QC
Tesla Owner
Model 3
Country
Country
#13
I always thought Tesla should offer a "winter regen" setting for RWD models that would use the friction brakes in front in correct proportion to the regen out back so that it would be as controllable as a full friction system in bad conditions. Obviously that's the intent of being able to turn down the regen, but it's a shame to have to lose the energy recoup just because it's icy out.
I'd KILL to have this on my Volt, as @garsh and @Bokonon point out the horrible delay that happens in transitioning from regen to friction when it senses loss of traction is nasty. Only thing I find poorly developed on the car. I'd gladly even take the Tesla solution of just being able to turn it off.
 

Dogwhistle

Top-Contributor
Joined
Jul 2, 2017
Messages
461
Location
Delaware
Tesla Owner
Model 3
Country
Country
#14
I always thought Tesla should offer a "winter regen" setting for RWD models that would use the friction brakes in front in correct proportion to the regen out back so that it would be as controllable as a full friction system in bad conditions. Obviously that's the intent of being able to turn down the regen, but it's a shame to have to lose the energy recoup just because it's icy out.
I'd KILL to have this on my Volt, as @garsh and @Bokonon point out the horrible delay that happens in transitioning from regen to friction when it senses loss of traction is nasty. Only thing I find poorly developed on the car. I'd gladly even take the Tesla solution of just being able to turn it off.
No kidding. My i3 can be a bit scary when it tries to full regen rear-wheel only on slippery roads. A bit disconcerting when the rear end tries to slide out around you! In the Tesla, it’ll be LOW regen if the roads look even remotely slippery!
 

fsKotte

Well-known member
Joined
Jan 18, 2018
Messages
264
Location
Walnut Creek, CA
Tesla Owner
Model 3
Country
Country
#15
Hmmm. This might explain my higher than expected wh/mi with the 3 (270-ish v. the rated/expected 240).

I just assumed, as with my former EV the Fiat 500e, that my M3 was using more regen when I hit the brakes (until it got to a slower speed, around 8 mph, where the pads would then come on exclusively). I thought that would be the ideal combination for efficiency, since in "Low" regen mode you coast more, and coasting to me seems more efficient than constantly having to re-acellerate due to the regen kicking in a lot, in "standard" regen mode.

But that posted video I guess is definitive - "Low" regen mode does not include any additional regen component when you hit the brakes. I'm gonna see if I get the same results when I hop in my example later today. . . .

I've got only 494 miles on my 3, and I've been using almost exclusively "Low" regen mode, partly because I just haven't gotten used to the one pedal, and more importantly it seemed to me that "Low" mode should be more efficient than Standard, but only because I assumed the brakes would be at least partly using additional regen when I applied the brakes, as with my previous EV's.

My average energy consumption, for the life of the car (494 miles), is around 270-ish watt hours / mile. That's above what I believe Tesla estimates that it should be under normal driving conditions/habits (about 240 wh/mi, I believe, they say it should be).

So now I wonder if that's because I've been using "Low" and not "Standard" regen. Sure, with a new Model 3, in the first 500-plus miles of its life, you're going to test the acceleration more than usual (because it's awesome, and riders want to experience it), and otherwise see how it performs, but now that I understand that "Low" mode really does not add ANY regen upon braking, I better switch to "Standard" and see if that makes any difference in my energy consumption . . . . .

The other reason I liked "Low" is that it seems you really have to use your right foot more with "Standard", constantly adjusting pressure/etc to achieve the speed you're looking for. Less stress on my right foot, it seems - even accounting for having to use the brake a bit more.

Anyway, I'm gonna do a test now: "Standard" regen for awhile, set one of my trip odo's to zero (and rename it "Standard Regen") and then see if the wh/mi gets better, or not.

Will report back . . . . . if all is as it seems, I should see an improvement.
 

fsKotte

Well-known member
Joined
Jan 18, 2018
Messages
264
Location
Walnut Creek, CA
Tesla Owner
Model 3
Country
Country
#16
No. Teslas don't add more regen when you hit the brake pedal.
I wonder, why not? Why *don't* they use regen any time you hit the brakes (which I was assuming they did, but they don't it turns out)? A lot of other EV's do that, and really it offers more flexibility for the driver.

If they blended regen with using the pads (or, better, just used regen when you hit the brakes until you got to a suitably low speed - 8mph or so), then *I* get to control the regen. I get the benefit of coasting in "Low" when I want to do that, but then every time I hit the "brakes", it would still be regen, and I'd still be putting energy back into the battery pack. Why is that such a bad thing, to always be using regen (or at least some extra regen) when you hit the brakes?

As it stands, "Standard" and "Low" regen settings are exclusively setting just what happens when you let your foot off the acellerator pedal, but do not include any regen in the actual use of the brake pedal. So, I can only choose between all regen all the time, or a little regen, but mostly brake pads. This is disappointing, really. Other EV's have this option. I just wonder why Tesla decided to forgo it.

Perhaps on the plus-side, this might be something that could be added with OTA (after all, they just fiddled with the brake settings after CR came out with their report, last week).

After all that typing, really what I'm most interested in knowing is why does Tesla not incorporate regeneration into braking (versus letting off the accelerator pedal). They're a bunch of smart folks, and I bet they've got their reasons, which I'd be happy to learn about.
 
Last edited:

jsmay311

Top-Contributor
Joined
Oct 2, 2017
Messages
411
Location
Chicago Suburbs
Country
Country
#17
I wonder, why not? Why *don't* they use regen any time you hit the brakes? A lot of other EV's do that, and really it offers more flexibility for the driver. If they blended regen with the pads (or, better, just used regen when you hit the brakes until you got to a suitably low speed - 8mph or so), then *I* get to control the regen. I get the benefit of coasting in "Low" when I want to do that, but then every time I hit the "brakes", it would still be regen, and I'd still be putting energy back into the battery pack. Why is that such a bad thing, to always be using regen (or at least some extra regen) when you hit the brakes?

As it stands, I now have to choose between all regen all the time, or a little regen, but mostly brake pads. This is disappointing, really. Other EV's have this option. I just wonder why Tesla decided to forgo it.
I think the main reason is engineering simplicity / braking performance.

Engineering a blended regen+friction braking system and doing it well is quite difficult. Keeping regen and friction braking controls separate is much easier to execute well.

I drove a pre-production Volt back in 2010 and the braking response in stop-and-go traffic was quite bad. There were "dead bands" in the brake pedal travel where you would depress the brake pedal further but get no commensurate increase in braking response. It kinda freaked me out a couple times. GM eventually got things fixed part way through the first model year and I think the brakes on my 2013 work very well, but you can imagine if a company with as many automotive expert resources as GM struggled to execute this well, Tesla would likely struggle even more.

Add in the fact that Tesla vehicles are geared more towards the performance / sports-car side of things, and having good braking response is even more important than with other EVs, so there'd be less margin for error.

Lastly, with many Teslas being RWD, I suspect that further complicates trying to blend increased regen and friction braking when pressing the brake pedal.

(Coming from an EV with blended regen, and being an energy-miser myself, I've come to prefer the blended appraoch, but most Tesla owners seem content without it.)
 
Last edited:

TOFLYIN

Active member
Joined
May 28, 2018
Messages
32
Location
Toronto
Tesla Owner
Model 3
Country
Country
#18
For the 7 years I drove my 1st Gen Volt, I downshifted (D-L) when I wanted to increase the regen. D being the equivalent to Low and L being standard in the Tesla. My wife and most people apparently liked to drive in L. I found that "downshifting" was better as I did not lose as much energy if I wanted to coast in D and slow down in L. The 2nd Gen Volts had a steering wheel mounted switch (like a gear shifting switch in some sports cars) which I think would be better. The new Honda Clarity has an interesting system of steering wheel mounted switches to increase or decrease the regen with 4 settings. So my point is couldn't Tesla make one of the steering wheel mounted thumb wheels to "dial in" more regen as you want it? Elon are you listening?
 

fsKotte

Well-known member
Joined
Jan 18, 2018
Messages
264
Location
Walnut Creek, CA
Tesla Owner
Model 3
Country
Country
#19
For the 7 years I drove my 1st Gen Volt, I downshifted (D-L) when I wanted to increase the regen. D being the equivalent to Low and L being standard in the Tesla. My wife and most people apparently liked to drive in L. I found that "downshifting" was better as I did not lose as much energy if I wanted to coast in D and slow down in L. The 2nd Gen Volts had a steering wheel mounted switch (like a gear shifting switch in some sports cars) which I think would be better. The new Honda Clarity has an interesting system of steering wheel mounted switches to increase or decrease the regen with 4 settings. So my point is couldn't Tesla make one of the steering wheel mounted thumb wheels to "dial in" more regen as you want it? Elon are you listening?
Yes, exactly this. I was actually thinking of the paddle on the Volt as I posted, as I understand that it gives you the ability of using more regen when you want/need it, and then you can still brake when you need that, but then you can still "coast" when that's most efficient.

It seems to me that you'd have a more efficient car if you could coast when you could/needed to coast, and then apply regen as much as possible when - and only when - you wanted to slow down.

Maybe I'm missing something about one pedal driving in "high" or (with Tesla M3) "standard" regen. It seems to maintain your speed, you're always having to apply energy to offset the regen, since it's always on. You're never coasting, then, but always applying energy against the regen. You're never coasting . . .
 
Last edited:

Mad Hungarian

Resident TOO Wheel/Tire Guru
Joined
May 20, 2016
Messages
1,073
Location
Montreal, QC
Tesla Owner
Model 3
Country
Country
#20
Hmmm. This might explain my higher than expected wh/mi with the 3 (270-ish v. the rated/expected 240).

I just assumed, as with my former EV the Fiat 500e, that my M3 was using more regen when I hit the brakes (until it got to a slower speed, around 8 mph, where the pads would then come on exclusively). I thought that would be the ideal combination for efficiency, since in "Low" regen mode you coast more, and coasting to me seems more efficient than constantly having to re-acellerate due to the regen kicking in a lot, in "standard" regen mode.

But that posted video I guess is definitive - "Low" regen mode does not include any additional regen component when you hit the brakes. I'm gonna see if I get the same results when I hop in my example later today. . . .

I've got only 494 miles on my 3, and I've been using almost exclusively "Low" regen mode, partly because I just haven't gotten used to the one pedal, and more importantly it seemed to me that "Low" mode should be more efficient than Standard, but only because I assumed the brakes would be at least partly using additional regen when I applied the brakes, as with my previous EV's.

My average energy consumption, for the life of the car (494 miles), is around 270-ish watt hours / mile. That's above what I believe Tesla estimates that it should be under normal driving conditions/habits (about 240 wh/mi, I believe, they say it should be).

So now I wonder if that's because I've been using "Low" and not "Standard" regen. Sure, with a new Model 3, in the first 500-plus miles of its life, you're going to test the acceleration more than usual (because it's awesome, and riders want to experience it), and otherwise see how it performs, but now that I understand that "Low" mode really does not add ANY regen upon braking, I better switch to "Standard" and see if that makes any difference in my energy consumption . . . . .

The other reason I liked "Low" is that it seems you really have to use your right foot more with "Standard", constantly adjusting pressure/etc to achieve the speed you're looking for. Less stress on my right foot, it seems - even accounting for having to use the brake a bit more.

Anyway, I'm gonna do a test now: "Standard" regen for awhile, set one of my trip odo's to zero (and rename it "Standard Regen") and then see if the wh/mi gets better, or not.

Will report back . . . . . if all is as it seems, I should see an improvement.
Here's where Tesla could learn something from GM.
With the Volt you have the choice of 1-pedal (well, up to a point) driving with the shifter in the "L" position, as it will regen decently just by lifting... or if you prefer you can select the "D" position and when the pedal is lifted it will just coast, but will regen when you apply the brakes.
I like both. When cruising on the highway I find I'm more efficient in D as it prompts me to coast more without even thinking about it. When bombing around the back roads I go to L and 1-pedal it, where it makes it easier to transfer the car's weight going into corners with just a lift of the right foot.
Seems to me that would be an easy setting to add.