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No regen yesterday (briefly)

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daniel

Well-Known Member
May 7, 2009
5,732
5,508
Kihei, HI
Yesterday was the first time I've ever charged in range mode. I didn't think I'd really need it, but there was just enough uncertainly about where I'd be going, that I did it. As a result (of course) I had no regen for a while.

I knew there's no regen when the battery is above some level, but it still kind of took me by surprise.

My ideal EV would have pure glide when there's no foot on either pedal, and would use regen on the brake pedal (as the Prius does). I find it's a more relaxed driving experience when the car can glide and the accelerator pedal only applies power, not braking. Both the Xebra and my ill-fated EV Porsche glide. With the Roadster, it's much harder to maintain a steady speed since a slight reduction in pedal results in strong braking.

And yet, it felt very odd to me not to have regen, and not to be able to slow down without using the brake pedal. I guess I'm getting used to the way Tesla does it.
 
Yes. At first I did not like/want regen. Then after a range or performance charge you will lose regen for a few miles and then I realized how much I really liked regen. I have always missed it. So this is by design as you do not want to overcharge a battery and this will protect the battery for you.
 
Like so many other unique characteristics of EV driving (home fueling, no shifting, no throaty engine sounds, one foot driving, etc.) once you "get it" then you wonder why everyone else is doing it the old way.
 
Well, for the steady speed there is cruise control. I am using it everytime I drive.
I hate the cruise control on the Roadster. The buttons are hard to press, and any time I need to slow down, the c/c disengages and has to be reengaged. Traffic is not a problem in Spokane, but there's enough of it that driving at the same speed for long is seldom possible. The Prius makes c/c very easy, as it's just a matter of moving the entire stalk, which I can do without much thought. But in the Roadster, those buttons at the end of the stalk are hard to find and hard to press and hard to get right. And then because the buttons are difficult, I risk accidentally putting on the high beams or turn signals.

The result is that I very seldom bother using it.

In the end, I'm torn: When I do want to maintain my speed right at the speed limit on city streets, it requires constant attention, and I don't like that. But when I'm driving it hard (which is most of the time) I'm constantly accelerating and decelerating, and then the one-pedal operation is really slick. So I guess that, being as it's a sports car, they've done it right. I just wish the c/c was easier to quickly engage and change speed. A stalk dedicated to just the c/c would have been nice.
 
I cannot stand having regen on the brake pedal. I've driven a number of Prii and the transition from regen to friction brakes is violent. It's impossible to smoothly move from regen to friction brakes. Keeping the brakes solely for braking is the right way to do it IMO - that way the brakes always feel the same.

I use c/c a lot and you get used to the buttons. I can do it by feel now and quite easily (but I agree that it's the worst c/c setup I've seen. I blame Lotus :p). You do know that you can click forward or backward on the c/c rocker to increase or decrease speed by 1 mph? The only thing that you have to remember is that when you go to cancel the c/c to apply some pressure to the accelerator so you don't slam into full regen upon c/c cancel. Initially I had thought Tesla should implement a more gentle application of regen when you cancel c/c but if I'm driving down the freeway and I see brake lights the car doesn't know how quickly to slow down so it defaults to full regen. Perhaps in future models they'll have adaptive c/c where the car could decide how quickly to slow.
 
I cannot stand having regen on the brake pedal. I've driven a number of Prii and the transition from regen to friction brakes is violent. It's impossible to smoothly move from regen to friction brakes.
In my 2004 Prius I absolutely cannot tell when the car switches from regen to friction brakes. There is no noticeable transition. I've never driven any other Prius, except the 2004 demo I drove before buying mine.

You do know that you can click forward or backward on the c/c rocker to increase or decrease speed by 1 mph? The only thing that you have to remember is that when you go to cancel the c/c to apply some pressure to the accelerator so you don't slam into full regen upon c/c cancel.
Yes, I know both of these things. But the rocker switches are awkward, and require heavy pressure, and if I don't press exactly the right spot nothing happens. I don't have any problems with the transition out of c/c.

Somehow I missed it: does Roadster have a Speed Limiter or not?
It does. Limited to 125mph I believe.
That's what I've read. I'd be terrified to ever take the car up that fast. I had it up to 90 once, for about 5 seconds, and I can say that the acceleration from 75 to 90 is breathtaking. The charts say there's less torque at those speeds, but I would not have been able to tell. (Caveat: the Roadster is the only sports car I've ever driven, so I have nothing to compare it to. My Xebra took 31 seconds to get from zero to 35 mph.)
 
I use the Roadster cruise control all the time. I agree that the buttons could be better, but at least I am able to use the Set (Accel) and Cancel buttons reliably. The Resume (Decel) button is the one I find hard to push. I also had the idea that when the Cancel button is pushed, the regen should come on more gradually so the driver has time to adjust the accelerator position, whereas when the cruise is cancelled by stepping on the brake then regen should not be delayed. In three years of driving I have been able to learn how to work around this by judging how much to depress the accelerator to match my current speed before using the Cancel button so I get a smooth transition. I think the +1 MPH adjustment is also too abrupt. My biggest complaint, though, is that the cruise works only down to 30 MPH, whereas I often drive on streets with 25 MPH limits strictly enforced. That is the first thing I'd fix if I had access to the software.
 
I agree with everyone that the cruise control buttons are not that comfortable. I got used to it and am quite confident with them, so on open roads I can drive even without using any pedal. With the 1mph clicks I adjust the speed, it works. I only find it a bit strange that the car accelerates noticeably every time you add 1 mph, but if you go up by 10 mph in letting it pressed down it feels alright.

Cruise control is far from perfect, but I'm glad it's there.
 
I guess I wasn't clear enough: Speed Limiter limits the power when car attains preset max speed. Unless you completely floor it (or disable the limiter) the car wont accelerate above that speed. This is very useful in city driving with lots of acceleration and rather low speed limits.

So, does Roadster have such functionality or not?
 
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I guess I wasn't clear enough: Speed Limiter limits the power when car attains preset max speed. Unless you completely floor it (or disable the limiter) the car wont accelerate above that speed. This is very useful in city driving with lots of acceleration and rather low speed limits.

So, does Roadster have such functionality or not?

Not. Unless you count 125mph as the limit. :smile:
 
In my 2004 Prius I absolutely cannot tell when the car switches from regen to friction brakes. There is no noticeable transition. I've never driven any other Prius, except the 2004 demo I drove before buying mine.

I can tell, but I have to really try hard to feel for it and it's easy to miss. The transition is the same in both the 2004 and the 2001--even though the programming is very different between the two cars.

My best guess is that if you only have driven brand new Prius, then you would be able to feel the transition. The Prius is quite tight when new and requires some driving to loosen it up. MPG improves during this time as well (mine increased by about one MPG every month for the first year). During this time you can also feel the engine shut down as well.
 
I'd be terrified to ever take the car up that fast. I had it up to 90 once, for about 5 seconds, and I can say that the acceleration from 75 to 90 is breathtaking. would not have been able to tell.

I've had my Roadster well over 100 (on a track not the street) and it felt perfectly stable. I'd have happily tried for the top speed if I didn't have to turn a corner before I got there.
 
I had mine up to 105 on a closed road, but had to brake because of a barrier at the end. It was about 1/2 mile long and I was drag racing a 750HP 1970 Monte Carlo (with drag slicks) to the quarter mile. The only reason I won was that his suspension was weak... it was the only thing he hadn't modified fully yet. He kept going sideways and had to feather. He caught me immediately after the finish line.