2009 Mini E: You Drive it Like a Slot Car

The term "regenerative braking" is familiar from the world of hybrids. In those cars, coasting energy is recovered by reversing the electrical flow through the electric motor, turning it into a generator that sends electrons back to the battery. The act of generating electricty saps a car's forward momentum and slows the vehicle, hence the name.

But regenerative braking in hybrids feels like nothing more than engine braking in a traditional car. You can't use it to stop the car or check-up for corners -- you still have to use the traditional brake pedal as usual. Braking-wise, the typical hybrid regen braking system is invisible and requires no change in driving style.

But this all-electric Mini E is different -- very different.

First and foremost, regenerative braking is much more critical to an electric car. Driving range is limited, and pure electric cars have no internal combustion engine to act as a safety net. Recovering every scrap of coasting and deceleration energy is vital. But every time you use the mechanical brake pedal you are robbing energy that could have gone back into the battery.

What's more, electric cars have batteries of much larger capacity than those found in hybrids, so they can accept a much more agressive level of regenerative braking.

Here's the Mini E's throttle/brake pedal, reference lines drawn all over it. They're not postioned precisely, but they do illustrate my point.

The rightmost line represents the at-rest position. The return spring snaps the pedal all the way back to this point when I step off the pedal.

The middle line is the neutral position. The car doesn't start to move until I get to this point. Take-offs were a little weird until I got used to it and understood why it happens.

Pushing beyond the neutral position (white arrow) towards wide-open throttle accelerates the car like any other vehicle.

When I relax my foot and back-off past the neutral position (green), the car slows. And, just like a throttle in reverse, the aggressiveness of the deceleration is proportional to the distance from the neutral point.

With my foot fully off the pedal the effect is strong enough to throw my head forward in a non-violent way. But it comes nowhere close to locking the wheels.

I kept looking in my mirror the first few times I experienced this in traffic, wondering if the folks behind would rear-end the Mini. After all, I wasn't touching the brake pedal. I needn't have worried because the brake lights are programmed to come on when anti-throttle is used to slow the car.

After a few tries I learned to modulate the throttle for braking and slowing, and that's when the Mini E started to get fun. It's easily possible to come to a controlled stop at a red light using nothing but the throttle pedal. Slowing for 90-degree rights where I have the green or a yield sign are easy one-pedal affairs. Roundabouts, had I had one in my neighborhood, would have been handled likewise.

And I'm not talking about stretched-out hypermiler stops, either. There's enough regenerative braking here to let you flog the Mini E like any Mini.

I found that the only time I ended up using the actual brake pedal was to fine-tune the 10 mph-to-zero portion of my friskiest stops, really tight corners and for unexpected traffic situations. No matter, the standard brakes are always there when the need arises.

The downside to all this, if in fact it is one, is this: the Mini E doesn't coast. It never glides along when my foot is off the throttle. I'm always using the throttle pedal to accelerate, maintain speed or slow down.

It all sounds weird, but it turns out to be fun in the Mini E. If this is how all all-electric cars will drive, then sign me up.

Now if we can only do something about the range, unified 240V charger standards and the price...

Dan Edmunds, Director of Vehicle Testing @ 911 miles