First Tesla Model S test drive with Elon Musk (video)

[daniel]

Originally Posted by darelldd

I need to stop you right there. You may intensely dislike the *idea* but I can't imagine how you could possibly dislike the process - without having at least experienced it. I know you've ridden in a roadster, but you have not driven with the ACP controller, have you? Yes it is different. Yes it is something new to learn. And yes you absolutely can coast (and yes, I still think it should be defeatable - as it is in the roadster and I see no reason to expect otherwise in the S). This method of driving is *FANTASTIC* to those of us who have used it - and in fact I've found nobody who owns an ACP-controlled car that wished it operated any other way.

Hating the idea that you haven't yet experienced is like gas-car drivers hating EVs because of all the new scary stuff that they have not experienced.

Okay. I have not driven a Tesla or an ACP-controlled car. But I've driven my Prius, which applies re-gen braking when I lift my foot off the pedal, and my Xebra, which does not. And I much prefer not.

However, you say it will be possible to turn it off, and with that I'd be entirely satisfied.

I like the idea of re-gen, but not the idea of lift-to-slow. I want my braking on the brake pedal, and I like the way the Prius does the brake pedal: re-gen braking when you press lightly; friction braking when you press hard, or below the useful re-gen speed. I don't like the way the Prius does the accelerator pedal. Yes, you can coast, by applying just the right amount of pressure. But it's easier to coast in the Xebra where you just leave both pedals alone.

[PeakOilGarage]

Then need a neutral position for regen on the acceleration pedel. On the Roadster when you lift off of the acceleration, it almost feels like you are braking as the regen kicks in. You don't even need to hit the brake pedal to slow down to a crawl speed.

It would be nice if they had a neutral position on the acceleration pedal so that you could coast.

[daniel]

Originally Posted by PeakOilGarage

Then need a neutral position for regen on the acceleration pedel. On the Roadster when you lift off of the acceleration, it almost feels like you are braking as the regen kicks in. You don't even need to hit the brake pedal to slow down to a crawl speed.

It would be nice if they had a neutral position on the acceleration pedal so that you could coast.

You mean that there is no neutral position on the accelerator of the Roadster, as there is on the Prius? That's even worse than I thought!

My point is that it would be much better to keep the braking on the brake pedal. And, as with the Prius, have the brake pedal apply pure re-gen until you press it hard enough to indicate that you need more braking than re-gen can supply, or the car was going too slow for re-gen, and then apply friction braking.

The Prius does it right on the brake pedal, and this is one of the things I love about it.

The Prius does it wrong on the accelerator pedal, and it sounds as though you are saying the Roadster takes that wrong philosophy to an extreme. Apparently Darell likes it that way. But I like the way my Xebra does it: The accelerator is only for accelerating, and the brake pedal does all the braking.

BTW, here's an odd discrepancy: The Zenn (in some versions) has re-gen braking. Sean Rarey of Grants Pass Electric Vehicles has discovered, and confirmed on multiple vehicles, that disabling re-gen braking on the Zenn increases range.

[Fibb222]

Originally Posted by PeakOilGarage

Then need a neutral position for regen on the acceleration pedel. On the Roadster when you lift off of the acceleration, it almost feels like you are braking as the regen kicks in. You don't even need to hit the brake pedal to slow down to a crawl speed.

It would be nice if they had a neutral position on the acceleration pedal so that you could coast.

Ha. I knew it. All this talk about pulse and glide in an EV that people go on about in various threads is nonsensical. The fact that there is a neutral position on the prius' go pedal was a lucky fluke and the whole concept of pulsing (accelerating "briskly") in a EV is nonsensical.

I agree that gliding in an EV would be nice. I sure was impressed with Darrelldd's video of the EV1 gliding at 60 mph and barely slowing down. Darell's EV1 video.

Overall, would the occasional glide, if done right, actually use less electricity than always on regen?

[Flying White Dutchman]

that music is iritating.
and i dont want too drive with that bright LCD screen during the night so i hope it can be dimmed..

but it looks nice haha

[daniel]

Originally Posted by Fibb222

Ha. I knew it. All this talk about pulse and glide in an EV that people go on about in various threads is nonsensical. The fact that there is a neutral position on the prius' go pedal was a lucky fluke and the whole concept of pulsing (accelerating "briskly") in a EV is nonsensical.

I agree that gliding in an EV would be nice. I sure was impressed with Darrelldd's video of the EV1 gliding at 60 mph and barely slowing down. Darell's EV1 video.

Overall, would the occasional glide, if done right, actually use less electricity than always on regen?

Pulse and glide improves mpg in a gas car because the gas engine is so much more inefficient outside a very narrow range of rpm and power output that it's beneficial to run it in that very narrow optimal band (the pulse) and then shut it off for a while (the glide). The Prius was the first car to make this approach practical, because of the ease with which it shuts off its engine, and the relatively efficient way it starts it up again.

An EV is a horse of a different color entirely. An electric motor (unlike a gas engine) is extremely efficient at low power output. Therefore the most efficient way to drive an EV is to accelerate gently, and then maintain constant current to the motor (analogous to constant throttle in an ICE) until you want to stop, and then coast (glide) to a stop (keeping in mind that following the flow of traffic may be more important than maximizing efficiency).

However, an EV that requires you to be either applying power or applying re-gen, without a "neutral" accelerator position, won't allow you to do this. And it's easiest when re-gen is on the brake pedal, and the accelerator is only for sending current to the motor.

I don't think the Prius's pedal operation is a fluke. I think it was designed the way it was intentionally. Toyota wanted it to feel like an automatic, which moves toward a constant, slow, speed when you do not touch the accelerator, but which has a spot where just enough gas is given the engine that it seems to coast.

[Fibb222]

Originally Posted by daniel

I don't think the Prius's pedal operation is a fluke. I think it was designed the way it was intentionally. Toyota wanted it to feel like an automatic, which moves toward a constant, slow, speed when you do not touch the accelerator, but which has a spot where just enough gas is given the engine that it seems to coast.

Until I hear something official from the original design team that they designed the pedal to provide the user a neutral glide point, I'm going to say it was a fluke. A fantastically useful fluke mind you....

I've never heard Toyota officially advocate pulse and glide.

And I want to something like Argonne labs to tell me whether some gliding in an EV is better than always-on regen coasting.

[daniel]

Toyota will not advocate P&G. Toyota wants you to "just drive it." I'm not saying they sat down and said "our pedal must have a neutral point. I'm saying that their intention of making the car behave like an automatic, necessarily meant that there would be a neutral point.

Sean Rarey of Grants Pass Electric Vehicles disabled the re-gen in several Zenns, and found they uniformly got greater range. I'm not sure you could convince Argonne labs to repeat his experiment.

[Fibb222]

Originally Posted by daniel

Sean Rarey of Grants Pass Electric Vehicles disabled the re-gen in several Zenns, and found they uniformly got greater range. I'm not sure you could convince Argonne labs to repeat his experiment.

Thanks, that's a start.

[donee]

Hi Fibb...,

There were a few pages in "The Prius that Shook the World" about the pedal operation. Its no fluke, it is designed that way.

The differences are that they put the coast point waaaay back, and the full off deceleration is much greater than most automatics they were trying to mimic.

And that is actually good, because it gives a whole bunch of accelleration dynamic range. I find that very handy in traffic.