The 2014 BMW i3 is primarily a battery-electric car, but buyers can choose to add an optional range-extending two-cylinder engine as well. BMW suggests that the car's ability to deliver its range will make the range extender unnecessary, but we suspect that in the U.S. many customers will want it anyhow.
Like any battery-powered car, the BMW i3 has smooth continuous torque from takeoff. It will accelerate from 0 to 60 mph in "approximately 7 seconds", BMW says, and 0 to 35 mph takes just 3.5 seconds. We observed a speed of 134 km/h (83 mph) with the car still accelerating; top speed is given as 93 mph. On the road, the i3 moves out crisply and its nimble handling and tight turning circle of 32.3 feet make it a joy to navigate in crowded city streets. Even in Amsterdam, where any given street may feature trams, buses, commercial trucks, cars, taxis, motorcycles, scooters, cyclists, and pedestrians all within inches of each other, the i3 was easy to place and a pleasure to drive.
The i3 is also a fine highway car, within the limits of its range, but we found it slightly sensitive to sidewinds and quite firm riding.
The electric BMW's 22-kilowatt-hour lithium-ion battery pack in mounted in the floor and liquid-cooled. It powers a 125-kilowatt (170-horsepower) electric motor that produces 184 lb-ft of torque to drive the rear wheels. That makes the BMW i3 the only rear-wheel-drive electric car on the market aside from the Tesla Model S. The motor is located under the load deck on the left side of the differential; at the right is an empty space where the range extender and generator package goes on cars ordered with it.
The BMW i3 differs from every other electric car, however, in its approach to regenerative braking. The solution BMW chose distinguishes the i3 drive experience from electric cars that simply mimic the behavior of a gasoline car with an automatic transmission. The strong regenerative braking makes the i3 the first production car we've driven since the original Tesla Roadster that truly permits one-pedal driving. And the effort BMW put into its well-calibrated control software really shows.
The feature can catch new drivers unaware--on our first drive, lifting off the accelerator while going down a parking garage ramp slowed the car to a complete stop, pointed downhill--but it takes only a few minutes to learn. There's no idle creep, though we didn't miss it. And BMW has retained a gliding or coasting mode, between acceleration and regen, although the software control is now so seamless that you have to watch the power display through the steering wheel to find it. There's no tactile or seat-of-the-pants indication that the motor has disengaged, unlike the cruder software used in the BMW ActiveE test fleet, when you could feel the motor disengage.
Because the regenerative braking can slow the car by recharging the battery at up to 50 kilowatts, the brake pedal only triggers the friction brakes--it does not induce or increase regeneration, which is controlled entirely from the accelerator pedal. In most uses, once a driver has learned how to modulate the accelerator, the friction brakes rarely need to be used in real-world conditions. They're mostly for sudden or panic stops.
We noticed that in both BMW i3 cars we tested, there was a slight creak from the front of the car just as it came to a stop using the brake pedal. BMW engineers said this is a slight slippage of the pad on the disc, a sound normally masked by engine and transmission noise in other cars. That may be, but we've not experienced it on any other electric car; the engineers said they are working on a fix for the problem.
To start the BMW i3, the proximity fob must be in the car, and the driver's foot must be on the brake pedal. The start button is on the inside of a rotary controller behind the steering wheel on the right that lets the driver choose forward or reverse, and also holds a "Park" button. The electric parking brake is far enough back on the tunnel, at the base of the storage bin and armrest, that we had to have it pointed out to us.
Buttons on the console let the driver select "Eco Pro" or "Eco Pro+" mode, to stretch battery range a bit further (BMW says about 12 and 25 percent, respectively). Unlike Eco modes in most other cars, the BMW i3's efficiency modes leave the car responsive and capable of keeping up with traffic. The EcoPro+ setting more aggressively restricts the energy devoted to heating or cooling the cabin; it's the "wear a down jacket" setting that will keep the car going as far as it can in cold winter weather. A kickdown function in the accelerator lets drivers override either EcoPro mode when sudden performance is needed in unexpected driving situations.
The i3's ride is well controlled, but the stiffer sidewalls of the very tall, narrow tires mean it's not soft. During a handling test, it was relatively easy to get the front tires to squeal on fast, sharp turns. We also noticed that the rear of the car jittered and skipped in fast cornering on broken surfaces. And because the car's heavy battery pack is mounted low, in the floor, but occupants sit straight up on top of it, the sensation of body roll is amplified. The BMW i3 rides well enough, but it's not a car you're going to want to take to track days or slalom courses.
Our two test cars were delivered with full batteries that registered available range of 132 km and 141 km (82 and 88 miles, respectively). It's rated by the EPA at a range of 81 miles, and because the sum of distance traveled and distance remaining stayed close to those original figures on our test cars--regardless of driving style--we expect the BMW i3 to deliver real-world range of 75 to 90 miles. It earns one gold prize, however: For 2014, the BMW i3 is the most efficient car of any kind sold in the U.S. It earns an efficiency rating of 124 MPGe, or Miles Per Gallon Equivalent, a measure that indicates how far an electric car can travel on the same amount of energy that's found in 1 gallon of gasoline.