Tuesday, March 20, 2012

I am an Electronaut

Warning: This post really has nothing to do with LAX or airplanes in general, beyond the fact that I took some of these photos on an airport.

I've got a new set of wheels: It's a BMW ActiveE. Said another way, it's an electric BMW: essentially, it's a 128i with the gasoline engine and associated hardware replaced by an electric motor and 192 lithium-ion battery cells. This is the second electric car field test model from BMW; the first was the MINI E. BMW built about 1,100 of these cars, of which 700 are being assigned to test markets in the United States. As such, I am more or less paying for the privilege of being a beta tester (BMW calls these people "Electronauts"); at the end of the two-year lease period the car goes back to BMW. In 2013, BMW plans to introduce their first production electric car, the i3, and a lot of that model's hardware is getting proven in this car. This is my first experience with an electric car (I don't think golf carts really count), and I'm looking forward to it. As I write this, I've had the car a little over a week and have put about 400 miles on it so far.

The first question everybody asks is how far can it go? The published range is about 100 miles, although that is dependent on driving technique. The car has an energy-conserving setting that stretches that to about 110 miles by reducing power to the motor and air conditioning, and I've been using that setting almost exclusively. My daily commute to work is around 42 miles round trip, so theoretically I could make that trip twice before recharging.

The next question is usually how long does it take to recharge? This depends on the charger being used. The car comes with what amounts to a trickle charger that can be plugged into a household 110-volt outlet. This charger gives about four miles for every hour of charge. Put another way, if you drive four miles it will take an hour to recharge the car. As mentioned, my daily commute is about 42 miles both ways, and the recharge time for that is over ten hours. Fortunately, because of the car's capacity, I don't have to recharge the car while I'm at work if none of the public charging stations or outlet-convenient parking spaces is available. Thus far, the longest day I've done is 92 miles, and it took over twenty hours to recharge the car after that. There is a much quicker option: a wall-mounted charging station. The charging station cuts the charging time down to a much more reasonable four hours, but requires 220-volt power and must be installed by an electrician. I've got one ordered for the house, but it has yet to arrive.

The charging port is located behind what is normally the fuel filler door

The trickle charger that comes with the car, shown here with a 12-pack carton for size reference.

The third question I get asked is what's it like? In a word, quiet. At speed, there is a whine from the motor, but it's not objectionable and is easily covered by the radio. The tire and wind noise is the same as any other car, but is more easily heard because there's no engine making even louder noise. There's also a noticeable lack of engine vibration, especially when stopped at a stop light. With the radio and air conditioning off, the car is still and silent when stopped, and would be indistinguishable from parked except for the instrument indications.

The other big difference from a gas-powered car is the regenerative braking. When the driver lets up on the accelerator pedal, the electric motor becomes a generator driven by the car's momentum, and recharges the battery by a modest amount. The amount of regenerative braking can be regulated via the accelerator pedal, and it is possible for the car to essentially coast down the road. Alternatively, it is also possible to bring the car to a virtual halt without using the traditional brakes. Naturally, it takes a bit of practice to get used to this - but not as much as you might expect. The bigger adjustment for me has been when I get back into a 'normal' car and have to remember to use the brake pedal.

The electric motor is mounted in the trunk, above the rear axle. About a third of the normally-available trunk space is lost to the motor.

After a trip to work and back, with an errand along the way, the trip odometer shows almost 47 miles (and it actually was 47 miles, since I was late to reset the odometer)


  1. Cool! I remember when the attorney I worked for got a brand spankin' new M3 off the showroom floor in Manhattan Beach. I loved the color but the car road like it was going over railroad tracks.

    This electric version BMW sounds like a wonderful car for short commutes.
    Enjoy your new baby.