ReGen level shifter pedals for Model 3

[JeffK]

Coasting (that is non-powered, non-regen driving) is the most energy efficient movement.

I'm not sure why I waste my time... again when you must slow down because of slower traffic ahead so coasting (in the EV sense) isn't even an option... you're providing nothing but a straw man argument. One thing that'd be really helpful is to read the OP and the OP's second post in this thread.

Options are regen or tap the brake. Slowing the car by adjusting CC is an example of regen.

If a person has that much trouble moderating their speed with the accelerator pedal then they might need other modifications of the car for handicap accessibility.

 

[ccutrer]

???
I think you just don't get what the advantage of coasting is. Imagine the following situation (this happens daily on my commute as well as any other drive):
You leave your town (speed limit 50 kph) and accelerate to the speed limit of the open country road (100 kph). The terrain is flat. With our Touran or the e-Golf I tested I would press the accelerator until I hit 100 kph, then let go of the pedal completely. Those two cars (as well as the B-Class ED or the Ioniq BEV on the regen off setting) would then coast along at 100 kph for a long time without losing much speed, even longer if the terrain has slight downward stretches in between. This can mean amazingly long stretches can be driven without using the accelerator at all, thus saving energy. Now say the terrain changes to downhill, or you enter another town. With those regen adjustment paddles you simply set the regen to a higher level and voila, one pedal driving as you describe on your command.
I always bugged me on my Model S test drives, that I had no such possibility. As soon as I lifted my foot from the pedal, regen kicked in, whether useful or not. Those coasting drives I described above would not have been possible, meaning I would have had to drain the battery more than necessary. Think about it, regen under normal conditions can only give you back part of what you have taken out. If you don't take the energy out in the first place due to coasting, you don't have to put it back in again later.
I can fully understand Bob Llewellyns enthusiasm about that feature, which he displayed both in the Ioniq review as well as that of the B-Class ED. And don't forget he drives a Model S as his standard car, so he surely knows what he is comparing. And no, I am not calling you Shirley

That seems incredibly complicated. Just turn on cruise control, and the Tesla will use the absolute minimum amount of energy necessary to keep you at 100kph. Yes, coasting/gliding if no input of energy is necessary. Remember that there is no idle torque in an EV. If there is no energy being applied to the motor, the car is effectively in neutral (in a similar vein, Park in a Tesla actually doesn't do anything to the gears - it actuates the regular brakes. And you can't accidentally put it in park while at speed, and grind the gears). If you have dual motor, it will even torque sleep between the two motors, which ends up being even more efficient, which is why an AWD Tesla has better range than a RWD one. There's simply no need to constantly be going between neutral and drive and applying a bit of power to get back up to 100kph. In fact, by your own admission of slowing down (regardless of how) and speeding up, over and over again, it's _less_ efficient than just letting the car perfectly maintain your exact speed with minimum amount of energy.

 

[ccutrer]

Thanks, that is exactly the answer I was looking for. I was hoping for a solution that didn't involve switching regen modes all the time or having to put my foot on the accelerator either. It sounds like the Tesla cruise control will work just fine. In my current car, each flick of the cruise stalk only changes the speed by about a half mile per hour. So, on the highway when I need to slow down several miles per hour it was easier to take it out of cruise (instead of flicking the stalk repeatedly), it would slow down fairly quickly then I could change lanes and resume my original speed. If I can do 5mph changes with the Tesla that should be perfect and let me avoid the hard regen of turning it off completely.

For everyone that mentioned AP, I know that that would solve the problem as well, I'm just not sure if I'll be getting it, with the price increase I'll need to consider it and compare it to other options.

Totally. Tesla's "interface" for cruise control is by far the best I've ever used. I always hate the cars that make you turn cruise "on" before you can do your initial set speed. Or that don't have any way to temporarily cancel cruise besides brakes. And then how it anticipates what speed to resume at if it's been canceled (previous speed if you haven't turned onto a different road, and are still under the previous speed, speed limit + personal preference delta if this is the first time enabling cruise in this session, or after canceling and turning onto a different road and you're still under that speed, current speed if you're above the max in the previous two cases, or use a flick down rather than a pull to enable to enable at current speed that's lower than the otherwise inferred speed. It sounds a little complicated, but the end result is that the car seems to anticipate how fast you want to go).

 

[David99]

It's interesting, this discussion comes up over and over. I think it's mostly from people who do not drive Teslas. Tesla has made regen perfect. It's just what you expect and how it makes sense. The accelerator pedal is now a speed pedal. The more you push it down, the faster the car goes, the more you let it go again, the more it slows down. All speed related control is conveniently on one pedal. It works just wonderful.

Some just can't seem to let go of the old ways that come with the limitations of an ICE. You have separate controls for acceleration and braking and now people are stuck in that way of thinking and want to add in regen as a third set of controls, hand pedals. That just makes no sense.

In a Tesla you can adjust your speed with just one foot/pedal. You can adjust both acceleration power and regen power from zero to full very easily and smoothly and conveniently with you foot. There is no advantage or benefit to brake it up to separate controls. If you want to coast, just hold the pedal at the same position, JUST LIKE YOU WOULD when you want to keep the same speed on a freeway. Coasting is way overrated. It is not a magical state of driving that would be super efficient. You have all losses that you have one way or another. Coasting is nothing more than letting the car slow down very slowly without control over how fast it happens. Again, it is the old way of thinking driving an ICE car where you have no regen.

Every time you hit the brakes in an ICE you are destroying (kinetic) energy. You can save fuel by looking ahead and putting the car in neutral and let it coast to a red light if you are lucky and have the space and the cars behind you are not getting annoyed with you. In an EV you don't need to do this. You can slow the car down as traffic conditions need and get energy back. The fact that it's not 100% efficient doesn't make it a bad option. Coasting isn't more efficient. Letting the car coast from 50 to 0 over let's say one mile means you are going an average speed of 25. If you drive at 50 the entire mile and then regen just at the end to bring the car to a stop you are driving an average of (almost) 50. If you want to look at it this way, you use less energy for driving that mile, but NOT because coasting is more efficient. It's because you are driving slower. That's all.

 

[david_42]

Although it never went into production, there is a Swedish design combines the accelerator and brake. Toe forward for acceleration, heel down to stop. Jam it down and the accelerator disconnects. the idea was to eliminate the time it takes to move your foot from one pedal to the other. Automatic collision avoidance systems have rendered it obsolete for the original purpose, but it would be great for controlling regeneration.

 

[Topher]

again when you must slow down because of slower traffic ahead so coasting (in the EV sense) isn't even an option...

Hypermilers have this concept that they call 'looking ahead'.

Thank you kindly.

 

[Topher]

All speed related control is conveniently on one pedal.

But I don't just want speed control. I want power control (both out and in).

Thank you kindly.

 

[Dan Detweiler]

I ran into a similar conversation on an early Volt forum. The hypermilers looking to get every possible mile out of every possible watt. I get it. It's like a contest with them and that's fine.

The general car buying public just wants to drive the car. If they have a pleasant experience then it is a good car...period. This is what Tesla does really well. Just drive the car and enjoy it for what it is.

Dan

 

[mhan00]

I had a chance to sit in a Chevy Volt recently and when the sales guy mentioned the regen pedal by the steering wheel I was surprised. What would compel them to not use the existing control interface of brake/accelerator and decide they needed a brand new pedal? Its so natural when driving say a Honda Insight, a Prius, a Tesla, VW e-Golf, etc....

Imo the way Tesla does it now is excellent. You want regen? Stop pressing the accelerator. Some regen? Lightly press the accelerator. Want lots of regen and to come to a full stop? Press the brake pedal lightly and increase pressure as you approach the point at which you want to stop.

The idea of adding an additional steering wheel pedal, or two, seems a LOT more complicated. Do I have to press the brake slightly and pull one of the levers if I want to slow down more? What if I forget?

I have a 2017 Volt, and I love the regen paddle. It becomes completely second nature. I love being able to lift my foot off the accelerator and coast while using the paddle to engage regen to slow down when I need to and hit the brake when I need to stop. The Volt also has an "L" mode which engages regen pretty aggressively upon lifting the foot from the accelerator, and I have to say I prefer the paddle since feathering the accelerator takes a bit more effort.

I would actually prefer Tesla include a paddle or just enable us to use the shifter to toggle between light regen and full regen, but if they don't I'm sure I'll get used to feathering the accelerator when I eventually get my III or S.

 

[saltsman]

Just to clarify, on the GM vehicles (Volt, Bolt, or Spark), regen works best with the decelerate (brake) pedal. Pressing the decelerate pedal provides a fully variable amount of regen up to max regen. Once max regen has been reached, the car mixes in friction brakes as needed to match the drivers commands. From a safety point of view, this is pretty nice since it allows the driver to slam the brakes at any point during a slowdown with no hesitation in moving the foot over. It is also familiar to most drivers. One pedal to go, the other to stop.

Driving in L (as opposed to D) allows a GM vehicle to drive somewhat like a Tesla where high regen is applied when lifting pressure off the accelerator (one pedal driving), but with the added advantage of still more regen still being available on the decelerate pedal.

The paddles on GM vehicles are not variable and are largely a marketing gimmick. This paddles actual use is surpassed with fully variable regen available on the accelerate and decelerate pedals.

Of all the things Tesla got right, having regen available on the decelerate pedal is the one feature it would be nice to borrow from GM.

 

[David99]

But I don't just want speed control. I want power control (both out and in).

Thank you kindly.

That is exactly what you have with the way Tesla is doing it. You can adjust the power both ways perfectly with one pedal.

 

[Topher]

That is exactly what you have with the way Tesla is doing it. You can adjust the power both ways perfectly with one pedal.

Sure would be nice to have cruise control for that (power, again, not speed).

Thank you kindly.

 

[David99]

Just to clarify, on the GM vehicles (Volt, Bolt, or Spark), regen works best with the decelerate (brake) pedal. Pressing the decelerate pedal provides a fully variable amount of regen up to max regen. Once max regen has been reached, the car mixes in friction brakes as needed to match the drivers commands.

Having never driven a Volt or Spark, how do you know and control between regen and friction brakes when both are on the same pedal and both are activated by pushing it?

 

[Topher]

Having never driven a Volt or Spark, how do you know and control between regen and friction brakes when both are on the same pedal and both are activated by pushing it?

You don't. If they do it the same way as a Prius, it is controlled by the computer. Regen is used until it can't support the level of braking requested, or under 7 mph. The transition is very smooth and mostly unnoticeable (again on the Prius), unless you haven't used the friction brakes since the last rain, in which case you get some grinding to get the rust off.

Thank you kindly.

 

[David99]

You don't. If they do it the same way as a Prius, it is controlled by the computer. Regen is used until it can't support the level of braking requested, or under 7 mph. The transition is very smooth and mostly unnoticeable (again on the Prius), unless you haven't used the friction brakes since the last rain, in which case you get some grinding to get the rust off.

Which EV do you have?

 

[ccutrer]

Which EV do you have?

(@Topher this is said in jest - I really do -- mostly -- appreciate your input )

None. Then he'd have to worry about conserving every single Watt-hour. With an ICE, he can be blissfully unaware</troll>

 

[lklundin]

Hypermilers have this concept that they call 'looking ahead'.

Thank you kindly.

Maybe you were trying to be funny, but it is exactly when looking ahead and seeing slower traffic that the measured reduction of speed via regen is useful.

 

[Topher]

Maybe you were trying to be funny, but it is exactly when looking ahead and seeing slower traffic that the measured reduction of speed via regen is useful.

And if you look further ahead, you can perform the same action with coasting. For a net gain in energy.

Thank you kindly.

 

[Topher]

(@Topher this is said in jest - I really do -- mostly -- appreciate your input )

None. Then he'd have to worry about conserving every single Watt-hour. With an ICE, he can be blissfully unaware</troll>

I'll put my worrying about conserving of every single watt-hour against anyone's here. That is what "Energy Curmudgeon" implies.

Thank you kindly.

 

[Buckeye2320]

I understand how it works, I'm just trying to find out if I can continue to do what I have been, or something close to it. Since no one has said so I'm guessing I can't without turning off regen.

Tesla has the same feature as a normal ICE car with Cruise Control. If you click the Cruise Control Lever up, then you increase speed by +1 MPH, or if you click down it reduces speed by -1 MPH. If hold up or down on the Cruise Control Lever for 2 sec or more, then the speed will raise/drop +/- 5 MPH.

Hope that helps.