Regenerative braking vs Coasting

Regenerative braking vs Coasting

My apologies if this has been covered already, as I'm new here.

My current vehicle uses an ICE with a manual transmission. Being curious about hype-rmiling techniques, I occasionally disengage the gearbox an let the car coast. At other times, simply letting go of the gas pedal in a high gear will cause the car to slow down over a long period of time. Both of these techniques will increase the measured MPG average according to my car's computer.

My concern involves something I read that the Tesla Model S would immediately engage the regenerative braking system if the gas pedal were let go. Is this true? Can one not coast in a Tesla?

Have there been studies done regarding the cost/benefit ratio of immediate regenerative braking vs coasting?

If this is true, I would strongly recommend your software includes an option for the customer to select their desired behavior.

Thank you,

SteveU | 9 september 2011

Sigh. This has been discussed before. There doesn't seem to be much agreement on the answer.

In my opinion, the Roadster lets you do anything you want to with respect to coasting or regenerative braking. You just adjust (with your foot, of course) the position of the accelerator pedal. If you push down you go faster. If you let up you go slower. Whether your foot position cause the car to draw power to accelerate, draw no power (coast), or generate power (regenerative braking) depends on where you position the pedal, how fast the car is going, and what the terrain is like (if you are going down a hill you can maintain a constant speed and draw no power while uphill you can't).

For me, the way the Roadster works is completely intuitive and easy. Others have complained it is completely wrong and broken.

VolkerP | 9 september 2011


rumors have it that in Model S there will be user-adjustable regen. Setting it to zero would be equivalent to coasting, but Tesla may chose not to allow zero as a valid setting. Regen braking is a requirement for a highly efficient EV.
Try driving a roadster and see how it feels to accelerate/decelerate with only one pedal.

ggr | 15 september 2011

@SteveU: I can't recall an instance of an owner of a roadster (that is, someone who's done more than just a test drive) who complains about its regen-on-the-accelerator behaviour. So I think there IS agreement, among those who qualify to have an opinion...

Volker.Berlin | 23 november 2011

Here's another thread that deals with the topic, including a confirmation that the Model S will most likely allow for driver-adjustable regeneration:

AlfredG | 26 november 2011

Regenerative braking is well chosen in the Roadster. Within minutes I felt at home. The car feels very controllable and safe.

I would have failed my driving test by coasting with a disengaged gearbox or by pressing the clutch. This type of coasting is considered to be dangerous. We were trained to shift down seamlessly before every turn and to hold the car with the engine braking as much as possible. Also in local traffic it was compulsory to choose appropriate gears to be able to slow down at least partially with the engine alone. In this way, in an emergency, you already slow down while moving your foot to the brake.
- Alfred

Brian H | 26 november 2011

Yes, to that extent the positioning of the goose pedal is similar to partial clutching, and engine braking, etc. Really miss that stuff driving automatics.

DHrivnak | 28 november 2011

I drove an EV before the Roadster and really liked the coasting capability. BUT after a few weeks with the Roadster I have to admit I really like the regen as set up in the Roadster. If one is a hypermiler I agree regen is not ideal but I think the set up in the Roadster is safer and your fellow drivers will thank you for it.