Driving a Nissan LEAF into the unknown

User interface designers have a tall order when it comes to creating a smooth transition for drivers switching from conventional cars to electric ones.
Written by Mary Catherine O'Connor, Contributing Writer

I just returned from a week-long reporting trip during which I drove a 2012 Nissan LEAF from Seattle to Wenatchee, Washington, and back again. I put 487 miles on the car, crossed a 4,000-foot mountain pass, twice, and plugged in everywhere from a friend's house to a swanky downtown parking garage to a mountain town with a population of 202.

But first, I spent 15 minutes trying to move the car out of a parking space.

Let me be clear: this does not reflect horribly on the design of the Nissan LEAF. I was given all the information and instruction I needed. It was all neatly printed out and placed on the passenger's seat (thanks Page One Auto). It would have taken me about three minutes to carefully read the "getting started" page. Instead, I figured I could wing it. I was doing a silly thing: pressing the parking button while also trying to put it in reverse. And like any insane person, I kept repeating this move, expecting a different outcome.

Finally, I did what I do whenever a new electronic gadget fails me. I turned it off, took a deep breath, and restarted. This time I tried moving into reverse without pressing "P" on the shifter and, bingo, it worked.

But there's another interface that took some time for me to get used to: the car's state of charge indicators.

The LEAF's display shows the number of miles left on the battery at any given time, based on the driver's recent driving pattern. Because I was driving on a mixture of city streets and open highways, I found myself constantly distrusting the mileage number displayed on the dashboard.

As I sat atop Stevens Pass, having climbed up 4,000 feet from sea level and really taxed the LEAF's battery, the display showed about 19 miles left on the charge. My destination was Wenatchee, a good 57 miles away. However, I'd be driving down to just 780 feet above sea level. That meant that thanks to the regenerative motor, the car's battery would gain charge as the car traveled downhill and as I braked. Overall, I'd be gaining -- not losing -- battery range as I drove down from the summit.

I knew I would make it, because just a couple weeks earlier, a rally of ten or so EVs, including LEAFs, had made the drive. They stopped at the same charging stations I'd stopped at, and in some cases were driving at even lower charging levels than I was. Still, the disconnect between the miles left on the battery, according to the dashboard, and the miles I knew I'd be able to drive was troubling. I was experiencing my first case of range anxiety.

The LEAF's mileage indicator is designed to calm range anxiety, but in this case it worsened mine. What would be nice, and what I expect Nissan will integrate in the future, is a way for the navigation system to account for the topography between your current location and your destination (which you would key or speak into the system).  With that feature, the navigation system would be able to predict how much power the motor will be regenerating during a long downhill drive, or how much it would suck up during a long uphill drive, and therefore more accurately predict the driver's charging needs.

Talking to other LEAF owners, I learned that to get a more accurate idea of how many miles are left on a charge, drivers look at a different display that shows a number of bars. Each bar represents about 7 miles of travel. Many EV drivers even purchase an aftermarket "state of charge" meter as a second step and for more clarity.

All of this goes to show that user interface designers have a tall order when it comes to creating a smooth transition for drivers switching from conventional cars to electric ones.

Image: LEAF interior, Nissan Motors

This post was originally published on Smartplanet.com

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