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Any brake pedal blending for more regen?

10K views 45 replies 21 participants last post by  PNWmisty 
#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
 
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#5 ·
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.
 
#6 ·
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.
 
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#10 ·
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.
 
#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.
 
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#14 ·
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!
 
#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.
 
#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.
 
#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?
 
#19 · (Edited)
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 . . .
 
#22 ·
I was just thinking today that I wish Tesla would add a Regen setting like 'natural', which would be the same as the low setting until the brake is detected, then switch to standad until you hit the accelerator and then go back to low.

This way you can relax your right foot more and the grab point is somewhere closer to the zero accelerator input, so when you remove your foot completely it doesn't throw you forward .
 
#23 ·
Me, too. This also, in my mind would be the most efficient way to do things. Coast when it's appropriate/convenient, and regen when you need to slow down. As it stands, the "one pedal" driving that everyone talks about really seems to me to be not efficient and would not increase range, because you never get the advantage of momentum to go forward; you're always needing to push through the regen resistance to move forward. The only thing I can think of, is when you're pressing the accelerator in "standard" (high) regen mode, the regen resistance is actually switched off and is only engaged when you decrease pedal pressure. But it seems like it isn't, because as soon as you reduce pressure on the pedal, the regen is so immediate that it feels like it's been on the whole time.
 
#24 ·
fskotte -
I think you have a misunderstanding of how Tesla regen works.
If you're driving down the road at 50, the power bar (just below the speed display) will be showing a slight amount of power - it'll extend to the right of center. If you release a little pressure on the wheel, the power bar will retract to the center - that's the equivalent of coasting in neutral in an ICE. If you release a little more pressure, the power bar will extend slightly to the left - indicating a little regen is being applied and you should note the car slowing. Release a little more pressure, the bar extends more the left and you feel more regen. Take your foot all the way off, and you're at full regen and now you can start applying the brake if you need.
If the power bar is left of center, no power is being sent to the motor - instead the motor is regen-ing power into the battery. If the power bar is right of center, power is being sent to the motor and no regen is occurring.
 
#25 ·
My comments come from only driving manual transmission before this, and being used to pulling my foot all the way off the pedal in gear. I like the way the low regen feels, but the efficiency is at about 285 wh/mi for me, so I'm going to give standard regen a go and see if I can get used to it.

My main beef with standard regen is that the zero point between go and regen is a slightly depressed pedal, and if you let all the way off quickly t slows too fast, so you're always feathering it slightly on. I'm having a tough time going from 3 pedals to 1.
 
#28 ·
It's funny how strongly people react to the regen behavior, some love it and some not so much

I have a friend who has driven my 3 all of 2 times. Both times he gets in the car and is flummoxed by the regen as he normally drives a manual Mini Cooper. I too have a ICE manual transmission car, turbo charged (so it even has a wider range of acceleration/deceleration behaviors than his Mini)

I have zero problems moving between cars and not tossing myself or passengers out the front window. It's not 'cause I'm special (well some may disagree o_O) but because I'm used to the behavior. I have zero problems not removing my foot all the way off the throttle to slow down in the 3.

I also don't simple take my foot off the gas pedal in the turbo car to slow down, it's a modulation there as well - it's just different amounts - but honestly I could also say that it is because my turbo gas car is a tiny thing compared to most vehicles driven in the USA and the 3 is quite big compared to it - so weight of the car also effects handling/braking/etc. I've driven tiny cars and stupid big box trucks and they all respond different to differing amounts of throttle modulation

I wonder if the folks (sans my friend) who have the biggest dislike of heavy regen are those used to driving slushbox automatics since they seem to have zero engine braking unless forcibly downshifted

Caveat - I have driven my Roadster in wet weather and you do need to be mindful of engaging full regen as it can provide interesting behavior out back due to rear drive and heavy rear regen - traction controll will step in here. The amount of wet weather I've driven the 3 in is pretty low - I expect to see the same behavior but hopefully a bit more refined since 10 years of development has gone by between the 2 cars.

I also spent too many years dealing with winter weather in the Boston area so the whole concept of controlling a car both with throttle and brake, as appropriate, is not new to me.

All that said, more options for controlling these settings wouldn't go unappreciated but it's low on my list of wishes for the Tesla software ;)
 
#32 · (Edited)
It's funny how strongly people react to the regen behavior, some love it and some not so much

I have a friend who has driven my 3 all of 2 times. Both times he gets in the car and is flummoxed by the regen as he normally drives a manual Mini Cooper. I too have a ICE manual transmission car, turbo charged (so it even has a wider range of acceleration/deceleration behaviors than his Mini)

I have zero problems moving between cars and not tossing myself or passengers out the front window. It's not 'cause I'm special (well some may disagree o_O) but because I'm used to the behavior. I have zero problems not removing my foot all the way off the throttle to slow down in the 3.

I also don't simple take my foot off the gas pedal in the turbo car to slow down, it's a modulation there as well - it's just different amounts - but honestly I could also say that it is because my turbo gas car is a tiny thing compared to most vehicles driven in the USA and the 3 is quite big compared to it - so weight of the car also effects handling/braking/etc. I've driven tiny cars and stupid big box trucks and they all respond different to differing amounts of throttle modulation

I wonder if the folks (sans my friend) who have the biggest dislike of heavy regen are those used to driving slushbox automatics since they seem to have zero engine braking unless forcibly downshifted

Caveat - I have driven my Roadster in wet weather and you do need to be mindful of engaging full regen as it can provide interesting behavior out back due to rear drive and heavy rear regen - traction controll will step in here. The amount of wet weather I've driven the 3 in is pretty low - I expect to see the same behavior but hopefully a bit more refined since 10 years of development has gone by between the 2 cars.

I also spent too many years dealing with winter weather in the Boston area so the whole concept of controlling a car both with throttle and brake, as appropriate, is not new to me.

All that said, more options for controlling these settings wouldn't go unappreciated but it's low on my list of wishes for the Tesla software ;)
I like the thought you've put into this, and the only explanation I can come up with for your friend who should be use to low gear compression in his manual cars is that some of us who regularly hop from manuals to automatics and back become "programmed" to expect a certain set of behaviours from each. So even though I've been a manual trans guy most of my life (swapped out not one but two slushboxes 'cause I hated them so much), when I don't have a clutch pedal I "automatically" expect the car to coast. It's 100% subconscious. I certainly had no problem adjusting to the Model S's I've rented, but prior to having the Volt it did take a bit of a transition period to overcome my programming.
 
#29 ·
After driving the Volt for so long I think I will miss the instant choice of regen mode (D vs L) and downshifting. There was 2 definite advantages... 1) Much more efficient if you want to do the work (not much work, but you had to pay attention driving to extend the range as much as possible). Now this may not be a problem with the range of the Model 3.
2)...After 170,000 km (106,000 miles) my brakes still look brand new. Almost no wear since even when you touch the brakes the first bit of brake pedal travel just increases the regen. No actual brakes until you really need them and depress the pedal past a certain point. This is so efficient that I found that after not using the brakes almost at all for weeks I would have to do a fast deceleration from highway speed to rub some of the service rust off the rotors (not visible, but would cause a bit of noise on braking that I did not like).

I know everybody has an opinion, but if you listen to the majority of those that have been driving EV's for years. Greater control over regen is preferred. If you don't want to use it you don't have to but it is nice to have the option. Here's hoping it will come in a software update, which is one of the great things about a Tesla.
 
#31 ·
For the first 500 miles, Blanche's EAP and TACC were not working. Tesla SC fixed that, but during the absence, I didn't like the fact that I had to keep my foot engaged with the throttle at all times. It led to fatigue and muscle cramps and I missed driving my slushbox where I could pull my foot off the throttle from time to time and relieve the stress.

Once EAP and TACC were in place, everything changed. I can engage either one and then I'm able to move my right leg to a more relaxed position. With these in place, I'm completely comfortable with regen. After 2800 miles, about 80% at highway speeds Blanche is averaging about 245 wh/mi.

EAP provides another benefit: the ability to relax your shoulders, arms and hands. You can maintain contact with the wheel, but rest your arm on your knee. When using EAP, I usually keep one hand on the wheel, resisting torque and keeping EAP engaged. I swap hands occasionally to avoid one hand fatique. After 4 hours of highway driving, my shoulders and arms are in way better shape than they are when I have to keep my hands on the wheel and actually steer. :)
 
#34 ·
This is my first car with Regen so a bit of a newbie. Switched to low and have been breaking like I did in my ICE.. learning here I should toggle my Regen more. But just to confirm that when I apply pressure to the break pedal I am cancelling all the Regen?
Thanks
 
#35 ·
This is my first car with Regen so a bit of a newbie. Switched to low and have been breaking like I did in my ICE.. learning here I should toggle my Regen more. But just to confirm that when I apply pressure to the break pedal I am cancelling all the Regen?
Thanks
No.

All this thread is saying is that pressing the brake pedal on a Tesla doesn't add any additional regen.

The brake pedals only apply/control the brake pads and have no effect on regen.
 
#36 ·
I have some of that programming, my 3 has creep enabled - some folks find that the height of blasphemy ;)
I tried turning creep off, which I thought would be great, but the amount of pedal travel/force required to get the car moving was weird. I felt like that made it more likely for me to get into an unintended acceleration situation if I thought I was in reverse or drive and I was in the opposite.

I wish Tesla had a manual transmission/neutral mode, where the car wouldn't apply any holds/etc and just rolled based on the topography. I'd take that in a heartbeat over creep/no-creep. I can always enable hold if I want anyway, so turning creep off seems limiting.
 
#37 ·
after reading these comments I'm really glad that Tesla does what it does and ignores most of these suggestions :cool:
I personally like the simple, two choice regen that doesn't involve the braking system. All the blended braking systems I've tried have had some issues.
A great example would be the Leaf version that seemed to work - until you need to brake hard really bumpy roads, at which point braking just quits completely.
 
#38 ·
I do hope they enable multiple degrees of regen at some point. Standard is very very heavy (obviously for 1 pedal driving) and low is pretty low. Slightly more than my Leaf. I'd like a middle ground as I can't see me doing 1 pedal driving but I'll probably try at some point.
 
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#40 ·
I really like one pedal driving on standard regen but think it could be improved with a small hardware change. That said, I think Tesla's implementation of throttle/regen has more going on than most are aware of. First, a few observations:

1) When holding a steady throttle position on a level road and encountering a steep hill, in an ICE car it is necessary to depress the throttle considerably more in order to maintain the same speed up the incline. On the Model 3 very little (if any) extra throttle is needed to maintain the same speed. Some might attribute this to the superior torque of an electric motor. I'm not sure it's that simple and think Tesla engineers have added in extra throttle when the load on the motor increases. Even computerized "throttle by wire" ICE engines do not do this.

2) When accelerating from zero, it is only necessary to depress the pedal slightly to begin. Therefore the throttle is in the same position during mild acceleration that it will be in during regen braking when coming off the throttle. How is that possible? The throttle mapping must be variable depending upon the speed of the vehicle.

3) Regen braking is about 50% efficient. Therefore, the most efficiency is obtained during cruise if it is not necessary to enter regen. However, when following another vehicle there is almost always a little speed variation. In this situation, particularly if the road is on an imperceptible decline, I find that I tend to "hand-off" between slight regen and slight throttle on to maintain appropriate following distance and it's difficult to discern which mode I'm in (or whether I'm coasting) without looking at the screen. Even then I find the narrowness of the regen/power indicator as well as the light green color of the regen indicator, makes it difficult to easily tell the difference between coasting and slight regen. I recommend Tesla make the indicator line thicker and use a darker green color to indicate regen. I will point out that I, like 10% of all males, have some form of colorblindness. While I can distinguish the green regen color from the background, it's difficult because both colors have roughly the same luminance.

4) I propose a hardware change to the throttle pedal. It involves a light spring pressure for the first third of pedal travel followed by a slight detent and then a more firm spring pressure for the remaining two-thirds of pedal travel. The first third of throttle travel would be reserved for regen braking and it would be necessary to push past that to begin accelerating. When cruising, the detent would be a tactile clue that the coasting position had been reached so drivers could efficiently coast for maximum efficiency when appropriate.

Change #4 involves a change that would be foreign to all drivers. However, I suggest that regen braking is essentially foreign to 99% of drivers anyway. Learning a slightly new driving technique is required either way.
 
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#41 ·
I really like one pedal driving on standard regen but think it could be improved with a small hardware change. ...

Change #4 involves a change that would be foreign to all drivers. However, I suggest that regen braking is essentially foreign to 99% of drivers anyway. Learning a slightly new driving technique is required either way.
In the spirit of the internet, I oppose this change vigorously just because I don't like it. An indent in the throttle position is an abomination!
 
#42 ·
1. This has more to do with how an electric motor is controlled compared to controlling a combustion engine. For a combustion engine, the throttle controls the fuel & air flow to the engine. The speed at which it spins is highly variable. For an electric motor, the accelerator mostly controls how fast the stator's electrical field spins. When you start going uphill, if you don't change that speed, then the rotor just starts working harder to keep up with that field. Now, I say mostly, because you can't keep doing this regardless of the load - eventually, the force working against the rotor will cause it to slip too far, or cause the motor to attempt to draw more current than the batteries can supply, or the rotor will overcome the tire's friction and cause traction control to kick in, etc.

2. Yes, throttle mapping is definitely variable. Much different at low speed than at higher speeds.

3. At low power levels, I wouldn't worry about it too much. Those differences are probably small compared to the constant load of the system.

4. YES! I remember wanting something like this when I got my Leaf. Some sort of "bump" in the accelerator travel to allow me to physically sense when the throttle position is at "coast", and hold it there a little easier.
 
#43 ·
When you apply the brakes, does Model 3 regeneration power increase at the same time and/or proportional to the applied pressure?

We're having a discussion in PriusChat and one non-Tesla owner claims they do not have 'blended braking.' This not something that sets my hair on fire but I'm curious.

Also, I'm a fan of shifting into "N" for coasting. It isn't a hard requirement but I didn't find the Owner's Manual really addressed whether or not we can shift between "N" and "D" while rolling. Does this work in a Model 3?

Thanks,
Bob Wilson
 
#44 ·
When you apply the brakes, does Model 3 regeneration power increase at the same time and/or proportional to the applied pressure?
regen happens when you slow down. stepping on the brakes doesn't directly increase the regen, except for the fact that you slow more while still rolling. Watch the green line on the dash to get an idea when regen is happening. (or the energy chart).
 
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