Car & Driver test drives and compares the 2014 BMW i3 and the 2014 Mercedes-Benz B-class Electric Drive.
The B-Class Electric Drive is almost identical to the conventionally powered B-Class. The car also shares 85 percent of its architecture with the CLA-Class and the GLA-Class. The power train was developed exclusively for this vehicle by Tesla Motors, a 28-kWh lithium-ion battery that sends electric power to a 177-horsepower electric motor.
The Tesla-powered Mercedes-Benz B-Class Electric Drive received its EPA ratings last month: 85 MPGe City; 83 MPGe Highway and 84 MPGe Combined.
The i3′s electric drive-train generates output of 125 kW/170 hp and peak torque of 250 Newton meters, which is immediately available from a standing start. The BMW i3 sprints from 0 to 60 km/h in 3.7 seconds and from 0 to 100 km/h in 7.2 seconds. Its top speed is limited to 150 km/h for efficiency reasons.
Here is an excerpt from their review:
Mercedes-Benz B-Class Electric
The B-class is indeed the most ordinary car Mercedes makes. It’s a five-door, front-drive steel box, or a VW Golf for people who want a Benz. It’s been available in Canada with conventional powertrains for a few years, but it’s hitting the United States for the first time now and only in Electric Drive form. Well, not all of these United States—just the 10 (plus Washington, D.C.) ZEV ones.
With thick and comfortable power front seats, a swath of wood across the dash, big circular eyeball vents, and the familiar COMAND system aboard, the B-class ED is immediately recognizable as 3935 pounds of pure Mercedes. Except for the Tesla parts.
The B-class ED is to the BMW i3 what the Honda Civic hybrid was to the Toyota Prius: A sensible retrofit, not an attention-getter.
The drive system comes from Musk Industries and consists of a lithium-ion battery pack under the car’s floor and a 132-kW electric motor in the nose. That’s 177 horsepower with an instantaneous 251 pound-feet of torque available. Paddle shifters behind the steering wheel let the driver select three levels of regenerative-braking action, with the most aggressive almost negating the need for the brake pedal during regular commuting.
Silent, laid-back torque production is the goal of most current Mercedes engines, so the Electric Drive in the B-class embodies a Mercedes ideal. On a full charge the B-class waltzed to 60 mph in 6.8 seconds and completed the quarter-mile in 15.4 seconds at 92 mph. All while feeling as if it were floating atop a meringue of electrons.
BMW i3 BEV
This car’s front tires are so skinny that they should be slicing ham. The exterior styling plays as parody of current BMW design. Inside, it looks like a Burberry picnic basket stuck in a fiberglass mop bucket. It feels as if it were whisking you to the exciting—okay, maybe not that exciting—future lying ahead.
It isn’t wholly successful, but the i3 is, like the Tesla Model S, a swing for the fences. That’s apparent at the doorsills, where unpainted carbon fiber shows off the radical structure of the car: a composite cabin sitting atop a welded-aluminum skateboard chassis. It’s also apparent on the scales, where the i3’s 2853 pounds undercut the B-class by more than a half-ton. BMW has placed the heavy battery low and at the center of the car with the electric motor slightly above and forward of the rear axle. So, the i3 has a slight 51.8-percent rear weight bias while lightweight body panels keep the center of gravity low—like a proper BMW.
