jgs
Active Member
In a world where Tesla was completely not resource-constrained, sure. As it is, I support them adding this feature to their to-do list, prioritized in the "when we have absolutely nothing else to work on" bucket.
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Why regenerative braking belongs on the brake pedal
- Thread starter JeffC
- Start date
ThosEM
Space Weatherman
That's a good question as it takes some time to get the hang of that. Like the friction brakes, you have pretty fine control of regen so you can iteratively adjust to get the stopping distance you want. OTOH, there is a limit when you've lifted your foot off the pedal completely, and if that isn't enough you'll know it's time to go for the friction brake pedal. Also you need to do that as you come to a stop, since the regen fades to nothing as you get below 5 kph or so, though it is noticeable when you, for example, first back out of a parking spot to drive a Model S.
My coworker had a Signature Edition Model S, he recently traded it in for a fully loaded Model S. I've been in his Tesla(s) hundreds of times. I'm quite familiar how it works, thankyouverymuch.
I also have nearly 120k miles on my Prius, so I know how that works, too. And when I get my Model 3, the Prius will be sold (I already have a potential buyer), and the 3 will become my primary vehicle. I was one of those folks waiting outside in the rain for several hours to put in my reservation on March 31st.
The 'brake pedal pressure to control regen' could probably be done through software. People like me aren't asking for you to lose your "I only drive with one pedal" mentality. Tesla can do things with software that other car companies can't do. So, why limit a car that could be nearly unlimited?
This may be true, but for desktop computers? Not a chance in hell. Windows dominates by a looooong shot. A PC interface is where you'll be doing your command line stuff, not a phone, so you can toss all the Android/iOS devices out the window. There are very few PCs in the world that will need the command line, and even fewer people that would be skilled at it.
The only people out there using the command line are the diehard Linux users or if your job depends on it. Nobody on OSX is using the terminal, so that cuts even further into the Unix crowd. I would certainly agree that Linux users have a better understanding of computers, but not for the reason you're suggesting. Would you say that those who drive stick have a comparable understanding of their vehicle? Didn't think so.
The argument here is that you can drive your car the hard way or the easy way. It doesn't matter which you do because the end result is the same. For computers, you can open up explorer by firing up the ol' command prompt and typing "explorer ." or you can simply click the button on your taskbar. Knowing how to do the former doesn't make you any better at opening up explorer; the end result is the same.
Linux users have a better understanding of computers because they go much more in depth, not because they do comparable tasks with the CL that a normal computer-user would do. There is nothing "more in depth" that a manual driver can do that an automatic driver can't. At least nothing that isn't obsolete.
Hm, discussing computers as an analogy for manual transmissions that was brought up on a thread about EV regen because..., I don't even remember. What is this "manual" or "automatic" transmission of which you speak. Why switch gears at all?
I find the human-factors arguments to be too simplistic: Driving an ICE uphill, what happens when you release the accelerator? You slow down, almost as if you had regen. If you're driving downhill, you'll continue to speed up. There is no fixed mapping of pedal position to acceleration. Drivers already have plenty of practice unconsciously accounting for the moment-to-moment differences in accelerator response. That's why most Tesla owners have no problems: after setting creep and regen to the desired levels, it only takes a few days to get very comfortable with the car's behavior.
Sometimes my Model S has full regen. Sometimes my Model S has no regen (when the battery is very cold). Sometimes I drive a car with significant transmission drag (creep). Sometimes I switch among these environments several times in a day and it only takes a few moments for me to understand the behavior of that car at that moment. Switching is not a problem for me, and I doubt it's much of a problem for most drivers.
Sometimes my Model S has full regen. Sometimes my Model S has no regen (when the battery is very cold). Sometimes I drive a car with significant transmission drag (creep). Sometimes I switch among these environments several times in a day and it only takes a few moments for me to understand the behavior of that car at that moment. Switching is not a problem for me, and I doubt it's much of a problem for most drivers.
SageBrush
REJECT Fascism
And another cough here.
Not to mention all the Uni students who connect to mainframes and supercomputers.
MS Office users may find the CLI difficult but that hardly detracts from its utility and power.
SageBrush
REJECT Fascism
interesting that you mention the Prius since it also has regen on the go pedal, just not as much.
If you want to use a computer analogy to the usability / human factors aspect of regen, single / dual pedal driving, or manual / automatic transmissions, try convincing a user of vi or emacs to use emacs or vi. Assuming you survive the attempt, you will understand that there is no convincing. Humans have preferences, and that is just that. Move on.
I personally prefer a manual transmission to an automatic one, and prefer Tesla's strong regen on the accelerator pedal over a manual transmission. I currently own one of each. But you may prefer differently. So be it.
I personally prefer a manual transmission to an automatic one, and prefer Tesla's strong regen on the accelerator pedal over a manual transmission. I currently own one of each. But you may prefer differently. So be it.
graphic
Member
Jerry, this is simple, and everybody OVERTHINKING this is wrong, Tesla is making it so we can buy the standard braking parts, not wanting to become a brake manufacturer itself is smart.
Why complicate something that works well, and set yourself up for a recall trying to RE-invent the wheel!
Bosch Ibooster is already on AP cars and so regen is already built into braking on tesla cars. Tacc uses it all the time and you don't even notice. But because of limit on amount of regen the battery can take, for the driver ui the regen input is currently limited to the accel pedal. If tesla is able to overcome the 60kw limit and make electricity instead of brake dust, I'm sure they will as they should. And no one will know because the Bosch I booster (which prius and other hybrids didn't have) has already solved the brake feel problem.
SageBrush
REJECT Fascism
Thank you for that not very thoughtful advice, but alas it didn't answer my question.
I did learn a little more about low-temperature, temporary regen limits; however, the 60kW limit still appears arbitrary. I have not found in my searching a battery-based limit for the 60kW of regen.
I don't know why Tesla limits regen to 60kW on the S/X but I don't think it's the battery.
Let me google that for you
Red Sage
The Cybernetic Samurai
There are those who reported that until an over-the-air update around mid-2013, regenerative braking on the Model S was more immediate. Perhaps not exactly 'stronger'... It was probably still 60 kW... But the mapping of the GO pedal was different. Unfortunately, though plenty of people loved the sporty feel that was very much like downshifting to just the right 'gear'... A lot more folks had very vocal passengers who complained of the lack of smoothness in the transition from acceleration to deceleration. They craved a more sedate and luxurious experience that coddled rather than rattled their behinds. Tesla Motors listened, and made the change, and certain folks (bonnie and/or Captain_Zap, I believe) have lamented the decision ever since. Personally, I'd love if they added a SPORT setting to the HIGH and LOW regen settings. That way everyone could get what they wanted.
I theorized before that if someone really wanted to have 'more' regen, they might have to sacrifice initial range to get it. Either the hidden, unusable portion of the battery pack set aside for protective anti-bricking would be enlarged, with a reserve especially for regen... Or they would just never fill their cars completely, maybe only to 85% or 90%, so that the remaining amount of capacity would always be there to accept regenerative input.
I theorized before that if someone really wanted to have 'more' regen, they might have to sacrifice initial range to get it. Either the hidden, unusable portion of the battery pack set aside for protective anti-bricking would be enlarged, with a reserve especially for regen... Or they would just never fill their cars completely, maybe only to 85% or 90%, so that the remaining amount of capacity would always be there to accept regenerative input.
wait... what oversteer? The theorectical in some very slippery conditions that would make a manual transmission car slide?
Ben W
Chess Grandmaster (Supervised)
It wouldn't necessarily require any changes to the brake hardware at all. The car can gauge its own acceleration, so it could clearly deduce when the brakes are applied, purely from its own motion. _Amplifying_ the braking through increased regen should then be fairly simple, particularly at lower speeds. For instance, if the driver is regen-decelerating at 30mph (typically ~30kW at that speed) and touches the brake, the car could detect it and momentarily boost the regen to 60kWh to amplify the physical brake effect. This would save some wear and tear on the brakes, and regenerate energy too, though in the big picture it's quite a minor amount.
I suspect the reason Tesla doesn't do this is because it could give the brake pedal an unpredictable "feel", if the regen level couldn't adjust precisely in sync with the friction braking. If there's even a fraction of a second lag, it could feel very wrong. This also could be a safety issue at high states of charge, if the brake "feel" becomes unexpectedly different because no extra regen can be applied.
In any case, what this approach cannot do is to completely _replace_ the friction braking with regen braking, even over a narrow range. That would require a custom brake pedal setup, and would be prone to the same inconsistencies as above. I don't know if the Prius has this issue, or if its regen is consistent regardless of SOC.
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