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A show-stopper for my eventual Tesla ownership...

I've followed Tesla from its early days when the Roadster was first introduced.
My enthusiasm has been steadily solidified.
I was 110% absolute that the model S Performance will be my next car.
...That is until I was "driving home" after a "beautiful" test drive a model S Performance few weekend ago.

Here are my 2 problems:

1. Show-stopper: Tesla cars are not able to "coast".
Letting off you accelerator and Tesla car "actively" slows you down.
In normal driving, both stop-and-go city traffic and highway driving, as a "green" driver, I "coast" my car quite often.
I even coast when temporarily breaking out of cruise control.
In my test drive, from the ram I merged into the fast highway. I got the Tesla to 100 mph in a blink (LOVE IT!!!) and without knowing it. Once I realized that high speed, as usual my foot was immediately off the accelerator.
I expected the car's momentum will gradually, steadily, and safely slow down to desired speed, i.e. 75 mph.
But...NO!
Tesla car "actively" slowed down significantly.
This is very dangerous as my Tesla would be slowing down and obstruct the vehicle behind me.
It thus required me to constantly pressing my accelerator to control the precise deceleration.
HATED THAT!

2. Another lesser but still is a show-stopper: Brake-lights are on...but I didn't even brake.
I supposed this is the programmed brake-light-on by Tesla's own implementation.
Due to its "actively" slowing down when foot-off-accelerator, Tesla turns brake lights on to warn folks behind us.
Though this is only a "visual indicator" and not as critical as the "not-able-to-coast" problem above, it bothers the heck out of me. It annoys me quite a bit when folks apply brake for no real safe-driving reason, especially on the highway.

Obviously I had a GREAT test drive.
I'm still crazily IN LOVE with Tesla.
I'm so PROUD that TESLA was invented and manufactured in the USA.
I even equate Elon Musk to Henry Ford for his innovations.
But I'll confess that unless I'm completely wrong on the above 2 issues or Tesla will correct them, I'll find myself not a Tesla owner :-(

Those who own a Tesla, please, please...prove me wrong! I'll appreciate you so much!

@Redshift, @Jolanda, @JaneW

Having more miles on your battery when you get to the bottom of the hill is not the same as "energy efficiency." @AmpedRealtor is correct about his theroy. I used to be an engineer, so I'll try to resolve the confusion.

If you can coast (in Neutral) down a hill without going too fast, you use zero energy to get down the hill. The only energy loss is in the friction of the tires and bearings and in wind resistance. On that same hill, if you turned on regenerative braking, you would charge your battery, but you would be going slower when you get to the bottom of the hill. Kinetic energy is 1/2mv^2. So, if you wind up going 1/2 the speed at bottom due to regenerative braking, you have 1/4 the kinetic energy. to get it back, you have to hit the accellerator and discharge your battery to get up to the same speed.

Since the conversion of kinetic energy to electricity (to charge your battery) is inefficient, you lose energy as heat in the electrical system of the car. - this is why the Tesla is constantly running those cooling fans over the inverters. Heating up the electrical system is wasted energy.

So, if you can coast without having to hit the brakes the whole way, coasting is better.

If you coast and wind up going so fast that you have to hit your brakes even once, you just blew a bunch of energy by heating up your brake pads and rotors.

If you can use regen to take the place of traditional braking, then you can reclaim SOME of that wasted braking energy as electricity. You'll still lose some of it as heat in the electrical system, but at least you save some of it.

In summary, don't compare regenerative braking mode to coasting mode. Compare regenerative braking to traditional braking, and compare ANY kind of braking to NO braking at all.

Regenerative braking is more energy efficient than traditional braking.
NO braking at all is more efficient that ANY kind of braking, because ALL types of braking waste energy in the form of heat (either heating the pads and rotors, or heating the electrical system).

If you can find a situation that allows you to avoid ANY KIND of braking altogether (e.g. coasting down a hill, or being pulled by a team of horses), then you will preserve the most stored energy in your battery/gas tank.

(note, for the sake of simplifying this discussion, I'm ignoring wind and road surface resistance, which might make coasting a little less efficient on any given hill, because you would go faster in neutral than you would with regen braking on - faster means more wind resistance, which is less efficient. That calculation is outside the scope of this discussion, depends on the headwind, the slope of the hill, rain, curves, quality of pavement, etc. Too hard to generalize with that level of detail)

Just my two cents. First, I have a Master of Science degree in Civil Engineering which required about two years of physics, so I am somewhat informed about this subject. In real life and in theory regenerative braking is better or in the worst case the same as coasting.

Two simple examples will demonstrate this. Two cars start at the top of a long downhill run say 20 miles with NO battery energy zero zip Nada. The car with the regenerative braking can equal the car coasting by adjusting his accelerator so it neither brakes or applies electricity to go faster than (gravity - wind resistance) would take him. End result both cars would in effect be coasting and their performance would be the same they would both come to a stop at the same spot.

Real world wind resistance does come into effect, wind resistance is proportional to the square of the velocity (a car going 40 mph has 4 times the wind resistance than a car going 20 mph). If the car with the regenerative braking maintains a constant speed down the grade his wind resistance would be less because he isn't going as fast and he would be charging his batteries as he descended. The car coasting would be traveling faster but at some point the wind resistance would equal the acceleration due to gravity and his speed would become constant. When he reached the bottom of the hill he would roll to a stop at pretty much the same place as the car with the regenerative braking if the car with the regenerative, when he reached a spot near the bottom of the hill, simply adjust his accelerator so he was not applying power to the drive train but was also not causing the regenerative braking to engage. Eventually he would equal the speed of the car coasting and ultimately roll to a stop at the same place, BUT because he had used the regenerative braking part of the way down the hill he would have some power left from the regenerative braking to continue further along the road. One caveat, both cars are NOT in a vacuum, if that were the case both drivers would be dead and this argument would be moot (at least to them).

I thought I could express this a little more succinctly but I guess not.

Bill Kiel

My 2 cents: the missing word here (unless I missed it in a previous post) is "feathering". I believe that is the proper term for how you handle the regen and maintain the proper speed. And feathering the accelerator on a Tesla is a new skill -- but one that you acquire fairly quickly. As someone pointed out, when you first take ownership, you tend to slow down too soon. But as an owner for four months, I can tell that it becomes second nature, and you feel much more in control of the car.

I do have a question, though: how do you know that the brake lights are coming on. I was unaware of that very impressive feature until someone from Tesla told me about it. Apparently, the car senses that it is slowing down (accelerometer?) and informs the car behind you so you don't get rear-ended. Sounds like a good thing, but my Tesla informant told me that he had to have someone drive behind him to confirm how it worked. How did @npham know the brakes lights were on? Does that show up on one of the displays!

At night and especially with wet roads you usually can see your own brake lights' reflections in the rear mirrors.

Something about your story sounds fishy. Have you driven any other luxury cars? A lot of them are now designed for you to calibrate your speed and acceleration with active involvement with the gas peddle and let the car sort out and figure out how to use engine power efficiently. A lot of them will go into regeneration mode, if available, and some would downshift. Most modern luxury drive-train implementations seems to assume if you take your foot off the gas peddle you want the car to slow down.

In my Mercedes E550 if I accelerate to a high speed and let go of the gas peddle the car downshifts almost right away and starts slowing down. It is very easy to adjust for that if you have half a functioning brain :)

Click the Tesla logo at the top center of your display screen. That will render a real time depiction of the car and will show you when your brake lights (and headlights, DRL's, etc) are on. You will be able to figue out exactly when they light up when you regen.

@npham1212

Here's the simple answer:

1) You're wrong.
2) You're wrong.

1) If you owned an S you would realize that coasting is easy; just adjust the Go Pedal so that you're not using any energy. It's extremely easy to learn how to one-foot drive and way more comfortable than the pedal-musical-chairs of an ICE. If you don't believe me, thousands of S owners would tell you the same thing.

2) All cars should have brake lights that activate on deceleration like the S does. Drivers of manual transmission cars often downshift to slow down, sometimes less-than-gracefully. If you're behind them you have zero indication that's happening - until you almost rear end them.

Sorry to be so blunt, but having owned a dozen nice ICE's in 30 years (MB, BMW, Lexus), nothing matches the Model S driving experience.

You're missing out man!

I wonder how many of us can jump on this before he responds :-)

Speaking of break lights ... does anyone know exactly how it is determined when they come on? I have seen a thread on this, but for the life of me can't find it (yes I have tried Volkerize). At first I thought it was energy based (i.e. in excess of x kw "in the green"), but that is def not the case. Is it a speed/deceleration thing? If so, I wish I had an easy way of knowing when they were on (some rear window break lights will have an indicator visible in rear view mirror) ... not sure why I care, but I do :-)

I see the brake lights come on when the "green" hits 30KW, not before.

If you touch the Tesla logo at the top of the touch screen, it shows you an image of your car, real time. If the door is open, headlights or running lights on, it shows that. It also shows you when your brake lights go on, either by using the brake pedal or when engaged by regen.

You can see that the brake light does not come on every time you reduce speed or the power gauge is green, but will come on if you completely remove your foot from the go pedal. You can see this for yourself in real time. So experiment with it a little and you quickly get a very good idea of when the brake lights come on with the regen. And you will see that it is entirely in your control!

One-pedal driving is one of the BEST aspects of the Tesla experience, and the one which mosts sets it apart from any other car. Once you really get a hang for driving in standard regen mode, it is easy, since it is perfectly responsive to you at every moment! And yes, you can "coast" using the go pedal to hold the line at no energy in or out. No transmission in a gas car can even come close to this level of responsiveness. Furthermore, the braking distance of the Model S is superior to gas cars because of the combination of braking + regen. Quicker to accelerate and quicker to decelerate, combined with superior responsiveness.

Learn to drive with the regen and you will never want to go back to manual or automatic transmissions!

Imherkimer, nice post.

WEB_SRFR;
+1
pedal

Efficiency is the goal of all the modern car tech, but it's much easier to achieve with the Tesla. It's "fundamental", Watson. ;)

Sucks for you then.

This is such an awesome care I wouldn't care if only came in raging pink.

@npham,

So many current MS owners have proved via this thread that you were wrong. Where are you and what do you want to say? If you are not a troll, please let us know what is your view on this matter now after learning from so many MS owners here.

1. I have owned a Model S since December. I coast all the time. In an an ICE car, making the car coast requires that you leave your foot off of either pedal (actually not true in an automatic, you also have to shift to N if you truly want to coast). In the Model S. coasting is done by depressing the accelerator to a certain position. It's not that hard at all. You CAN coast in a Model S. The input to the car is just different than you're used to.

2. The brake lights work really well and nothing should be changed about that.

PS earlier posts mentioned that you can turn off the regen. This is not true. You can set it to Normal or Low, but you can't turn it off.

*This*

is a "show stopper" ?

Really?

Just what sort of show is this?

I'm really curious to know what car actually meets your criteria.

Is there an EV that coasts to your satisfaction? If not, I have a hard time believing that the ability to coast is more important than overall energy efficiency and carbon impact [but at least you can coast into the gas station, I suppose].

sgc

If this is a show stopper.......maybe stepping a foot in Mobile should be for this poster............

@Kiel

I'm sorry, but you are not correct. The car with reg braking would go down the hill more slowly than the car in neutral. They would not come to rest at the same spot. Remember your physics: you can't get energy for free. If you bleed energy to charge the battery, you MUST take kinetic energy away from forward motion. This is obvious to anyone who drives a model S... When regen braking is on, the car goes slower. That's why it's called braking.

Do your thought experiment this way:
One car goes downhill in neutral.
The other car goes downhill with their foot pressing halfway down on the brake. Nobody hits the accelerator at any time.
do they stop in the same spot at the bottom of the hill, or does the car in neutral continue to roll farther?

You can't get energy for free. Anytime you convert energy from one form to another (kinetic to battery), you lose some to heat (inefficiency). Coasting is more efficient. If you start going too fast while coasting, turn the regen back on to control your speed and gain some charge in the meantime.

Normal regen makes lifting off the throttle feel very much like putting on the brake or downshifting n ICE.

Low regen feels pretty much like an ICE when you lift off the gas. The car slows a bit, but not dramatically.

Neutral feels like Neutral in a Tesla or an ICE.

If a driver can't find one of those options comfortable enough to feel save driving a Tesla, they are probably a really horrible driver. Some people just don't have good eye hand coordination, awareness of spatial relationships, or mastery of the multiple pedal dynamics involved in driving a typical car. We've all seen people that can't maintain a constant speed, people that brake whenever the road curves in the slightest, stop short at intersections then creep forward and stop again, or brake too late and have to mash the pedal to get stopped. These people will not likely be any better at driving a Tesla, regardless of settings. They might do better with low regen and creep, but they will still suck at driving.

I think Tesla did an amazing job of making the Model S speed up and slow down in a way that feels very familiar to the average ICE driver by choosing low regen and creep. Of course, a 7 liter AMG and a Tercel behave very differently, so moving from a big luxury sedan to a Tesla is probably easier than transitioning from an econobox.

For good drivers who notice the feedback from their car through the wheel, pedal and seat of the pants, the Tesla presents driving dynamics that are new and unique. They are easy to master is you have average skills and are a delight, if you like that kind of thing. I DO! One pedal driving is the best. Rolling out of the throttle and using regen to stop precisely where I want to is a brand new game to play. I like it far more than driving a manual. I was surprised by that. # years ago I had to give up three pedal driving and go back to a slushbox due to neck and back problems. Discovering this new game was a delightful surprise. I pity those who lake the skills to master or appreciate the new driving style the Tesla offers, but to each his own. If you like the ICE feel, put regen on low and turn on creep.

Tesla also got the brake/decel light algorithm spot on IMO. As mentioned by others, TAP THE T BUTTON AT THE TOP OF THE SCREEN TO SEE A RENDERING OF YOUR CAR ON THE SCREEN. This will show you when the brake lights illuminate. Whether from regen or braking, the lights come on an appropriate times to alert drivers behind that your car is slowing. I was not immediately aware of this feature when I got my Tesla in February, but I figured it out the first day. Watching that display is distracting so keep your eyes on the road and just glance down a few times under decel and it will ease your mind. A little tap of the brakes if your unsure will insure the brake lights will flash, but I don't find it necessary.

Driving a Tesla has profoundly changed me. I have confidence in my car that I did not have in any other car. I can pass, change lanes and merge with speed and grace that belie the weight and size of Model S. The new aural input that I hear due to the absence of engine noise heightens the pleasure. There are dozens of new revelations and subtle differneces that make driving a Model S a daily joy. Last week I discovered how deeply I have been changed when I had to drive the Mercedes that has been sitting idle since I got my Tesla. I found it distracting, disconcerting, primitive and lacking in every respect. I loved that car but the Tesla has changed me and I think I would find it difficult, if not impossible to go back to an ICE. I am regarded as a good driver by my friends and family. Nobody complains about my driving style, flinches, closes their eyes or prays. I could always jump into a new vehicle and adjust to it within minutes. Now I find driving my old car disconcerting. Even more surprising, the Model S is the first car I feel is "fast enough." I have yet to think "oh, if this car had just a little more grunt."

If the OP's story is a little hard to accept. Did he not mention his disdain of regan and did the rep not adjust it? Seem unlikely, but not impossible. If it is real, he should try again with regen turned down and creep turned on. If it still feels unacceptable, he should get a Camry or something of that ilk. I pity anyone who doesn't "get" the Model S. It's a major evolutionary step in automotive transportation, but it is impossible to make a car that is all things to all people

The troll hunters are smelling something. Again. The poster did respond on earlier comments (2nd page 7th post) and he may do again.

OT: With only two test drives and no car yet my first reaction would be to take the MS as it comes. It did not feel the need for coasting. Traffic is quite heavy where I live (near Rotterdam) and that was also true in Antwerp and Eindhoven. Holland is flat. The only coasting I can imagine would be entering a tunnel. I pass 3 of those on my every day commute.

I do have a question for those who say after a few days/weeks you get accustomed to the MS style (just about everybody). What happens when you have to drive an old fashion ICE car? Is it easy to remember you need the brakes? Did anyone 'forget' to press the brake in a situation?

I ask because I will be driving the MS 99% of the time but there will be times I need to get into our Toyota Auris.

Lush1: thank for your writing down your experiences, also nicely written. These are the things I enjoy reading the most and if possible should be made available on major blogs. Even I'd have to wait for GenIII, the MS is a dream car for me and I talk to friends about it in advance of any deliveries reaching Germany. At that time the press here will have way more coverage and I expect a run on the Tesla stores here.
Thanks again!

Fred O,

I don't think you will forget how to drive your ICE, but it will probably not feel as natural. The biggest problem for me is during warm up when the idle speed is at it's highest. When I lift, the car does not slow at all (on slow city streets) and I sometimes have to jump on the brakes a little harder than usual. The Mercedes does not get power to the ground as well as the Tesla so traction control on the ICE intervenes a lot when I drive it. Almost never happens in the Tesla. Parking the MB in the rain the other day and having to do a 4 point u-turn in my narrow street made me very nervous. The noise and lack of visibility gave me the feeling I might back into something so I had to take it very, very slow. I didn't have any mishaps but is was on edge. If I went back and forth more frequently, I would probably adjust more quickly, but I am clearly spoiled by the Tesla. I trust myself to adjust to conditions and drive appropriately for conditions, including choice of transportation, but I don't like driving the ICE at all.

Thanks Lush1. I guess changing between the one pedal MS (I know there are 2 pedals ;-) and the two pedal Auris Hybrid, is similar to changing between the automatic and the three pedal manual shift I have in my current Volvo. I have been doing that for years.

I have not been reading all the post here, but give me a brake. This is a show stopper. I am no longer a day to day forum reader, but I just had to weigh in. The reason why I don't read is because I am too busy driving and having a wonderful experience in the best car ever made. Shut up and buy the car, you will be happy you did.

@npham1212 - I may be one of the few people with an S who actually use low regen all the time. I do so because I the car feels smoother to me, much more pleasant to drive. I know how to drive in standard regen. It takes very little time to learn. I just prefer low regen and am not too proud to admit it.

I always have plenty of charge so I'm not concerned about the lost energy savings in low regen. And I'm not worried about wearing out the brakes sooner than standard regen because brakes are replaced free in the Tesla service plan.

As mentioned by posters above you can emulate coasting in the S by watching the energy usage gauge. And don't let anyone intimidate you into driving in normal regen if you like the feel of low regen better.

You can indeed get the S to both drive and feel very much like to what you are now used to.

TFMethane +2

@ddruz - I also use low regen almost all the time. The only time I switch to normal is for a long downhill.

"SHOW-STOPPER" my A$$!

Notice that the OP subject line has "MY EVENTUAL TESLA OWNERSHIP". He can't buy a Tesla yet and is just making excuses.

The Tesla already uses momentum most efficiently.
If your car goes downhill faster than needed, regen captures the waste. If you need to go faster than the downhill speed, you'll add a small amount of energy.

Just watch your usage monitor next time you go downhill, most likely you'll expend very little energy.

nppham1212 is not wrong....I feel the same way in that keeping the foot on the accelerator is a little straining. Although it's not a show stopper for me. It's a matter of preference and he only stated his preference. Everyone's post on this matter was helpful at first, but then it got nasty. I love my Model S and and was one of the ones who waited 1.5 yrs almost 2 years to get mine and didn't even test drive it until a week before I took delivery. VIN # 3964. I use this forum to help me get advice and prospective buyers may do the same. Troll or not, if the advice we give is in a way that will cause readers to think us Tesla owners are evangelizing robots who worship Elon Musk (I do worship him. My husband thinks I want to be Elon's next wife) and who get beligerant when anyone says anything negative about Tesla, we give ourselves a bad rep and turn off legitimate prospective buyers. Let's try not to do that. Or is it the trolls that defend Tesla in a negative way.....hmmm....

OMG!!!
I can't believe it! You guys are awesome! Your posts are so informative to read. I've learned so much from reading all of these posts.
Sorry for the late response. This weekend I had 5 parties to go, in 3 nights, home between 2-4 am... just spent an hour reading now.

But let me say one important thing before I will go into the details:
@hademarco@yahoo.comYou are my HERO!
Not only because you have hit the bullseye on keeping the foot on the accelerator is a little straining, but also your reason of if the advice we give is in a way that will cause readers to think us Tesla owners are evangelizing robots who worship Elon Musk (I do worship him. My husband thinks I want to be Elon's next wife) and who get beligerant when anyone says anything negative about Tesla, we give ourselves a bad rep and turn off legitimate prospective buyers.

Gosh! I LOVE you!
Or shall I say “I LOVE how your brain works!” ;-)

Exactly to @hademarco@yahoo.com's point, I was turned off by the degree of “blind love” from the few who has shown their disrespect, lack of civility to others. I’m not referring to any one post in this thread, but I’ve read it on another thread where a Tesla-enthusiast-MD expressing his genuine opinions and concerns. What were the responses? I’m telling you guys, it was disheartened to put it mildly.

Who with commonsense and reasonable knowledge can / will claim that any new product, especially as innovative and as exceptionally futuristic design as this wonderful Tesla, has achieved all of its technological superior objectives from day-one, or needs no additional enhancements / improvements, or has no presence of short comings?

Regardless, calling people names or even poking fun just because of a typo will severely negate the very assistance your message intends to deliver, not to mention it reflects poorly on the authors’ characters. It sure won’t be the same for me when I run into a Tesla owner from now on. Blind love seems to impede the ability to take an objective, unbiased pondering of Tesla Roadster / MS / MX perceived negativities.

To sum up this distractive / un-constructive behavior, I’d like to repeat a quote from another thread by @GReese | June 23, 2013
It's always better to mistakenly treat a troll with respect than it is to mistakenly treat someone with a valid concern as a troll.

Those points aside, while I’m certain that I’ll enjoy driving / owning the MS based on my own test drive, as well as experience shared here by many (thank you), I’m definitely deferring my MS purchase.

Here is the reason: I’m objecting to Tesla’s current decision to eliminating support for a very fundamental physic law: the ability to let the vehicle continue in motion (kinetic energy) without any artificial interference (i.e. standard/low regen) which slows down the vehicle above and beyond the usual physics attributes (quote from @ TFMethane’s great post) …the headwind, the slope of the hill, rain, curves, quality of pavement, etc. Tesla’s current design allows ONLY controlled acceleration and controlled deceleration.

I understand that it doesn't matter how we express our near absolute satisfaction of what the Tesla’s current capabilities are, or even how few among us blindly worships this new futuristic vehicle, that will dictate the course of Tesla engineers on “next release”.

I understand too that controlled acceleration and controlled deceleration are much more sophisticated to implement than to enabling such simple option as “a complete regen turn off”.

So…to all: I sincerely thank you for your time, efforts, and knowledge. Your posts are both intelligent and informative.
I learned more from here than from the test drive.
I will confess that the “standard regen” realization sadden me (a personal, subjective, and non-scientific reaction), however, the few un-constructive / negative comments here sadden me even more. To those, you had managed to turn down my enthusiasm from the prospect of sharing stories of fun driving experience that only Elon Musk and the crowd can deliver right here in the US of A.

Lastly, for those who thought I was a troll, just FYI, from my own initial quote
Obviously I had a GREAT test drive.
I'm still crazily IN LOVE with Tesla.
I'm so PROUD that TESLA was invented and manufactured in the USA.
I even equate Elon Musk to Henry Ford for his innovations.

Ciao...


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