The PluginCars.com crew just returned from a one-hour drive through San Francisco in the Nissan LEAF. I had the geeky thrill of driving down Lombard Street—the city’s famed winding street—in the LEAF. But the biggest eye-opener was what we saw on the screen in terms of driving range, as well as what Nissan’s Mark Perry told us about the LEAF’s battery capabilities. Here are the highlights:
When Nick Chambers, Zach McDonald, and Mark stepped into the car, the dashboard display indicated an average of 14.7 miles traveled per kilowatt-hour of energy used. A dozen or so miles later, we managed to reduce the efficiency to 13.6 miles per kilowatt-hour. Seeing those numbers shattered my expectation that EVs almost always travel 4 miles per kilowatt-hour.
Keep in mind that almost all of our driving in SF was stop-and-go low-speed driving in congested traffic. Mark acknowledged that the miles-per-kilowatt-hour metric would go down in highway driving. However, seeing the capability of the LEAF to squeeze that much mileage out of a kilowatt-hour showed how the total range of the car’s 24 kilowatt-hour battery pack, under fairly common conditions, could easily go way beyond 100 miles.
The key could be the effectiveness of the LEAF’s regenerative braking system. We spent about half the time in regular “Drive” mode and half the time in the “Eco” mode, which uses more aggressive regen. As a result, when we started out, the display showed 63 miles of range left in the battery—but around 12 miles later, the display showed 59 miles of range. Again, our driving cycle, with lots of braking at low speeds, gave plenty of opportunity for the regenerative braking to extend the car’s range.
The biggest revelation from Mark was that Nissan engineers are allowing 95 percent of the LEAF’s energy storage to be used. This stands in sharp contrast to the Chevy Volt, which only ever uses 8 of its 16 kilowatt-hour pack. In most conventional hybrids, the battery is never charged or discharged beyond 60 or 70 percent.
Mark believes that it will be a rare occurrence for a LEAF driver to dip so far into the state-of-charge. Regardless, Nissan is showing a great degree of confidence in the capability and durability of its battery technology to allow so much of its capacity to be used in those rare times. This could be a key differentiator from the competition. (Bear in mind that the warranty on the LEAF's battery is 8 years or 100,000 miles.)
Combine the big number for miles-per-kilowatt with the 95% battery usage figure to get a picture of a robust well-managed battery that—at least for in-town driving—could mean high real-world numbers for driving range.
Other tidbits:
- Acceleration was smooth and effortless on San Francisco’s very steep hills—regardless of the driving mode. It only took another inch or so of accelerator movement in Eco mode for the LEAF to confidently zoom up hills.
- During the city’s busy and noisy late afternoon traffic, the LEAF’s sound warning was barely audible.
- At 6’4”, I had plenty of head and legroom in the driver seat and backseat. Two large adults in the backseat would have no problems, and three can fit in a pinch.
- As expected in an EV, acceleration was brisk, quiet and smooth—and the handling and driver experience were uneventful. In other words, it drove like a competent compact car, requiring no adjustments or changes from how you would operate a gas-powered car. That’s a good thing.
That’s it for now. It’s been a tiring three days at the Plugin2010 conference in San Jose. We’ll be writing up more of our discoveries in the next few days. Also, Nick shot video of our LEAF ride in San Francisco, and will soon have something to show—including a detailed narrated visual rundown of the dashboard screens and features. Stay tuned.
UPDATE 7/30/2010: After receiving numerous emails and comments suggesting that we were off our rockers and/or mistaken and/or the LEAF's computer was broken, we reached out to Nissan to make sure that the 13.6-14.7 mpkWh number we had seen on the LEAF's computer was accurate. Nissan's zero emissions crew got back to us saying that the numbers are accurate and the computer is not broken. In fact Katherine Zachary, Nissan's Manager of Corporate Communications, wrote in an email, "Driving factors including city driving (rather than high-speed driving), Eco mode and Regen (and not running the AC full blast) all contributed to these results. It's worth noting they are right on par with other drives we have been doing on the West Coast (San Diego, Los Angeles and San Francisco were all over 14 mpkWh)." -- Nick Chambers
Photo: The LEAF in downtown San Francisco.
Very cool that you got such a lengthy, hands-on drive!
One thing that needs mentioning though is that there's no way... and I mean NO way that the Leaf will see anything near 13 or 14 miles per kWh on a regular basis with any sort of normal driving. If it managed 5 miles I'd be jumping up and down with joy. The expectation that "all EVs travel 4 miles per kWh" is actually a pretty high bar to meet! Any car larger or less aero than the LEAF won't be able to touch four. There could be many reasons why the display was showing something very high - I'm a bit non-plussed that Mr. Perry didn't offer up a logical explanation for the anomoly you saw.
I hate like heck to temper the excitement... but please don't expect the Leaf to ever achieve anything remotely near 24 x 14 x .95 = 320 miles of range! (that's 24 kWh x 14 miles per kWh x 95% SOC usage).
You'll notice that 24 x 4 is almost 100 miles - about what we can all expect to see.