Cruisin' in Neutral - Actually a blast!

[smorgasbord]

If you haven't tried hitting the "N" button while driving your Roadster v2.5 - try it! Not accelerating never felt so fast!

If you've read about how low friction the Roadster drivetrain is, but don't believe it, get onto an empty road and while moving at, say, 40MPH, shift into Neutral. It's pretty darn amazing. A Roadster in neutral just coasts and coasts and coasts.

So, besides the non-rush rush, what's interesting about this? Hypermiling. A fellow Roadster owner pointed out to me that while regen is great, true hypermilers want to coast. The thinking being that regen only gets back around 66% (and that's on the generous side) of what you expended, but you'd get more back by letting your car pick up speed going downhill and then continue to coast until the speed drops too low, and then provide power. In other words, the power stored in the moving vehicle is more efficient than converting that power into battery juice which is subsequently used to make the car continue to move.

While popping into Neutral is fun and easy, getting back into Drive can be a bit jarring. I need to play around some, but it doesn't appear that you can "rev the motor" by pressing the accelerator pedal while in neutral, but I need to see if pressing the pedal reduces the regen so the transition back into drive isn't so jarring. And, while this technique might save some watts, it surely seems like it would create more wear and tear on the drivetrain.

Anyone else experiment with this?

[zack]

Sounds fun! When my Tesla's back from Chicago I'll try it!

[Fabrizio]

If you fully charge the Roadster in Range mode, you will not have Regen for the first few miles - you get the same effect. Someone posted that they lost traction control and regen going over a bump in a curve, the Roadster accelerated on it's own - they were actually feeling the coasting sensation rather than unexpected acceleration.

[Doug_G]

First time I lost regen due to cold I thought my Roadster was trying to throw itself out of the parking lot. Of course it was just coasting with no regen braking. You're right... it really rolls!

[ChadS]

Yeah, that's fun. There's been a lot of enthusiast debate about the merits of coasting and regen.

The RAV4-EV doesn't have any regen by default; when you let up on the accelerator, you are coasting. There are two levels of regen that you can apply: there's a button on the shifter for low regen, and a "B" mode on the shifter for high regen. When driving the RAV, I move between them a lot--alternating between coasting and giving it a little juice when cruising, and turning on regen when I have to slow down. Trying to extend the range by coasting is fun to do every now and then; I don't drive the RAV that often. (Why would I when I have a Roadster? Although the real reason is that my wife prefers the RAV, so I have to drive the Roadster. Pity me).

Regen is indeed bad in that it wastes energy; it's only "good" when you compare it to braking which wastes more energy. If top efficiency is your goal, you never slow down unless you really have to, which is why coasting is a good efficiency default. Only when you "have to" slow down do you use regen (instead of braking). This is why some enthusiasts claim that the RAV's setup is better than the Roadster's.

I agree that it would be nice to be able to turn regen on and off (better yet: dial in a level for when your foot is off the pedal). But that really just makes it easier to get top efficiency; you can achieve the same effect by carefully holding the go pedal in the right position, or using neutral. For everyday driving in traffic, where you "have to" speed up and slow down a lot more to avoid annoying other drivers, having sizable regen on by default is a great thing (again, note that being able to adjust it and/or turn it off would still be great! I'm just saying it's a good default). It makes for really easy one-pedal driving that keeps you at just the right speed, yet the regen still is only used when you "have to" slow down. You just "have to" slow down a lot more often (along with accelerating faster) when worried about other drivers.

I figure the Roadster is already the most efficient car on the road, and I don't want ICE drivers to waste more energy than I'm saving to get around me, so I drive the Roadster using the go pedal to keep my speed where I want it to fit in traffic, and enjoy how simple it all is--it's the easiest car I've ever driven in traffic. I've tried neutral a few times, but just to test it out.

Truth be told, I'm not going to win any efficiency awards anyway because the Roadster is so much fun to drive, and I have a lot of years of slow hybrid and diesel driving to make up for. Maybe that's the real reason I like high regen on all the time in the Roadster.

[AndrewBissell]

I tried this extensively early in my ownership, but couldn't find any appreciable range gain so stopped. Btw I agree with the theory that it should work

[suxxer]

One could also try this:

Cruise at a speed >5 mph. Then shift into N. Floor the gas pedal (nothing will happen) and then shift into D (be sure the car is rolling otherwise you get a "gear shift not allowed error"). Now the car takes off instantly

[JRod0802]

...you can achieve the same effect by carefully holding the go pedal in the right position...

I have a question about this. I read that the roadster has "creep" built into it, so at 0 mph it doesn't have a "neutral spot" in the pedal. As you speed up the "creep" diminishes and then regen fades in. Once you hit a certain speed (like 10 or 20), does the behavior of the go pedal stop changing such that the "neutral spot" stays in the same position, or does the "neutral spot" of the pedal always change based on how fast you're going?

[smorgasbord]

Cruise at a speed >5 mph. Then shift into N. Floor the gas pedal and then shift into D. Now the car takes off instantly

Is this akin to the 0-60 times from a "rolling start?" If so, does anyone have a time to report?

[ChadS]

I read that the roadster has "creep" built into it, so at 0 mph it doesn't have a "neutral spot" in the pedal.

Correct. I think that creep goes up to 3mph and then disappears suddenly, but I am not sure.

Once you hit a certain speed (like 10 or 20), does the behavior of the go pedal stop changing such that the "neutral spot" stays in the same position, or does the "neutral spot" of the pedal always change based on how fast you're going?

Interesting question; I'm not positive. I could speculate, but I don't think it matters because there's not really a "dead" spot on the pedal. There's just a point at which you are neither doing any regen nor putting in any power. And whether or not that varies with speed, it will vary with inclines, wind, drafts from other cars...so there is some work involved to keep the power needle vertical to simulate coasting.