[NeilBlanchard]

Regenerative braking aka regen - is using the electric motor in the opposite way it is used to move the vehicle. The motor can be powered by energy from the battery to move the car - or the moving car can be slowed down, by using the motor to *generate* energy, that recharges the battery a bit.

So, instead of using the friction brakes to slow the vehicle - which simply turns the kinetic energy of the moving vehicle into HEAT - it instead is able to regain a portion of that stored kinetic energy of the moving vehicle, and turn it back into electricity that can be put back into the battery. Some energy is still lost (to heat) - but a good portion of it is regained, to then be used again. Regenerating ​electricity is an important way to make electric cars even more efficient than they already are.

While I am on the subject of the stored energy of the moving vehicle - the MOST efficient way to use this energy (that you have "invested" by accelerating the mass of the vehicle) - is to *coast* whenever possible. So, backing off the accelerator when you are anticipating a stop, or when you see that you don't need to keep accelerating - means that you stop using any more energy, and then use the stored energy of the moving vehicle - to continue to move the vehicle forward *essentially* for free.

This is why some electric vehicles - VW and Hyundai and Kia, among others - can coast by default. An electric car doesn't need to idle the engine when coasting (like an internal combustion engine (ICE) vehicle - so when they are able to coast (without any regen) when you lift your right foot, you can move the vehicle forward *for free*. This can vastly improve your driving efficiency.

Once you drive an EV that does this, you intuitively just learn how to do it. You will find that coasting opportunities are much more common than you would have expected them to be. And when you need to slow the vehicle down - use regenerative braking to do so.

BUT - this is why 1-pedal driving by default is problematic: just because regen is better than friction brakes, does NOT mean that regen should be implemented when you lift your right foot. Please understand that many EVs are designed to have some regen integrated onto the accelerator pedal - mainly this is done for an understandable reason - but in my opinion, this is short sighted - it makes a vehicle behave like an ICE vehicle.

But it negates the ability to coast.

One pedal driving takes the idea that if regen is a good idea - and it IS a good thing - then it leaps to the idea that MORE regen is better. I think that 1-pedal driving BY DEFAULT - or especially as the only option - is too much of a good thing, so to speak.

Here's why I think that having 1-pedal driving is not necessarily a good thing - you can try to "feather" the accelerator, to just keep the vehicle moving forward at a constant speed - but this takes a lot of effort, and you will inevitably accelerate (a bit or a lot) more than you need to, and then you will use regen to slow back down - which by definition, is less efficient than coasting.

Let's state the obvious: ​we are driving a vehicle (most of the time) to move ourselves / things from point A to point B.​ And the most efficient way to do that - is to accelerate only as much as needed, to accomplish that.

One-pedal driving is more likely to cause the driver to accelerate more than is needed, to just get from point A to point B. One-pedal driving tends to "encourage" a racier mode of driving - to accelerate right up to point that you need to stop. SINCE regen can only regain some of the energy "invested" in the moving vehicle - and since 1-pedal driving makes it essentially impossible to coast freely - it removes the best way to move the vehicle forward i.e. coasting. Coasting is the most efficient way to use that stored kinetic energy - so EVs that don't even have the option to allow coasting - is less than ideal.

If you live in a mountainous area, then having strong(er) regen modes when you lift your right foot ARE a good thing. We should trust the driver, and make it possible to choose whether you coast by default, or have mild/medium/strong level of regen, when you lift your right foot. I do think that regen should always be integrated onto the BRAKE pedal - and MOST EVs do this.

The big exception though - is Tesla. While most other things are very well designed on Tesla vehicles - and in the case of having very low aerodynamic drag, Tesla is better than most, if not all of other EVs available today - this design choice is a puzzling exception.

So, to sum up my points - we should have coasting by default on all EVs (at least as a set option), and we should have driver selectable regen modes, for having regen integrated onto the "go pedal" - and regen should always be integrated onto the "stop pedal".

Please discuss!