Mitsubishi i-MiEV Part I: Driving
In an earlier post, photographer Ian Merritt discussed his experience as the first staffer to take home the Japanese version of Mitsubishi's i-MiEV battery-electric car. In the following two-parter, I'll detail the driving experience and some of the drawbacks of what is essentially a silent car.
Our car had keyless access and keyless start like a lot of cars do nowadays. With the keyfob in your pocket, you can unlock the doors by pushing a button on the driver's door, and then start the car by turning a knob where the ignition key would be. Notwithstanding the fact that our car was right-hand drive, it was like a normal car in most ways. When you first turn it on, you hear some buzzing from the back, which is the electric power-brake assist preparing for the next stop. The sound then goes away and comes back only after you hit the brakes a couple of times. You don't hear it at all once you're on the move.
The i-MiEV (pronounced EYE-meev, according to Mitsubishi) has impressive get-up-and-go even with four occupants, as is the norm for electric cars. It doesn't make for lightning-fast sprints to 60 mph, but it's quite satisfying in urban and suburban settings. The transmission has the familiar PRND settings, plus Eco and B modes. Drive is the most like a normal car in that it lets you coast along when you lift off the accelerator. Eco gives you more engine braking (or motor/generator braking to be exact). The B setting, which we've seen on some hybrids, gives you even more engine braking. Coasting down a hill, I switched from Drive to Eco to B and felt the car decelerate faster with each change. With the greater braking comes more battery regeneration, as indicated on the charge gauge. This type of braking will boost the electric vehicle’s range.
With its increased regeneration, B turned out to be the most efficient mode. By controlling the car's acceleration and deceleration with the accelerator pedal, I maximized regeneration and made very little use of the brakes. Unlike hybrids, the i-MiEV's brakes don't regenerate energy. They're just normal brakes, and as such, they operate and feel better than brakes on most hybrid cars. But they actually rob you of efficiency by turning your inertia into heat in the brake pads rather than electricity in the generator. The best-case scenario is that you use them as little as possible, and the B setting does this best.
So what's Eco mode? It makes the accelerator pedal — there’s no gas, after all — less sensitive and provides more regeneration than Drive but not as much as B. Here's my problem with it: It doesn't just change the nature of the accelerator response; it limits your power. When you floor the pedal, the i-MiEV scoots from zero to 45 mph in about 7 seconds when in Drive and B. It takes 9 seconds when in Eco. Whether it's in an electric, gas, diesel or any other kind of car, an economy mode should always give you full power when the pedal is floored. It's the only safe approach.
Overall, the i-MiEV was a fun experience. Its shortcomings — top-heaviness, susceptibility to crosswinds and prodigious wind noise at highway speed— are a byproduct of the car, not its electric nature. (The "i" has been sold overseas for about five years with a three-cylinder gas engine.) Comparisons to the Smart ForTwo are natural, and we noticed similar problems with that car — plus a good many others.
That's not to say the electric aspect didn't have its shortcomings. I'll address those in Part II.