Nissan Leaf Energy Report: One Month = 13 Gallons of Gas

In its first full month of service, and in the hands of 11 drivers, our long-term Nissan Leaf consumed a total of 438.196 kilowatt-hours-worth of electricity from Southern California’s utilities. In those 31 days, it’s also covered 1379 miles, which after some arithmetic means a daily travel rate of 44.5 miles. Given that a single gallon of gas contains the equivalent of 33.7 kW-hr of energy, the electrical energy appropriated for the Leaf’s battery equals that of about 13 gallons of gas. And there are a fair number of compact cars that have fuel tanks maxing out around 13 gallons.

Our Leaf has been charged at various locations in its first month, but if it had only been charged at my residence, the entire 438.196 kW-hrs would have cost roughly $57 based on the $0.13-per-kW-hr I was most recently billed (the lowest usage tier out of five). But at 438.196 kW-hrs, that consumption amount would have likely landed me in the middle third tier, where a single kW-hr costs $0.24, yielding a $105 tab. With gas at $4 per gallon, that $105 would have bought me 26.25 gallons of gas.

We can hear the Prius crowd now, muttering that their car’s 50 combined mpg could have squeezed a very competitive 1313-mile range out of those same gallons. But show me a conventionally powered production car that can offer the equivalent of 106 mpg. That’s the good news with EVs.

It’s when we shift our attention to the 24-kW-hr battery that we see the Leaf’s biggest constraint. They’re space-consuming, expensive, and painfully slow to refill. If there’s one thing an electric vehicle supporter and opponent can agree on, it’s that battery-electric cars aren’t the most versatile driving solutions. Not yet, at least. If your garage-less apartment community or tyrannical condo association is only letting you keep one car on the premises, you really shouldn’t slap a deposit down on the Leaf unless you’re ready for an all-new lifestyle dedicated to babysitting an EV’s charging needs. I’ll tell you now: the hard-working, lithium-ion pack lusts for companionship.

I’ll provide an example. A Leaf depleted of any usable charge needs 25 hours to refill using a household 110/120-volt outlet (what’s called Level 1 power). On Level 2 power (that’s 208-240 volts), the charging time plummets to a still-substantial 7 hours and 30 minutes. Those times are according to the Leaf’s own readouts but we’ve found the estimated charge times to generally be on the conservative side, regardless of charging level. Using our AeroVironment-sourced 208-volt charger, the Leaf wrapped up some 20 minutes earlier than expected. But the promising detail is that finishing 20 minutes ahead of schedule isn’t at all unusual. In more than a few home charging sessions, anywhere from 15-30 minutes was knocked off the anticipated charge time. Our current record is a surprising one hour and 14 minutes before the original end time.

Now, which is more satisfying for the driver—being greeted with charging times that don’t allocate sufficient time, or with charges that finish earlier than expected?

Based on our observations, the Leaf’s trickle charger can add 1.0-1.25 kW-hrs per hour, though we should remember that not all of the electrical energy flowing out of the socket is dispersed to the battery. Ohmic resistance and other losses zap efficiency, so when you’re charging an EV, you end up paying for some extra heating. For reference, 1.25 kW-hrs would be the equivalent of slow-dripping 4.75 fluid ounces of gasoline into a container for an hour. That’s a bit over half a U.S. cup—one cup is 8 fluid ounces. And per the Leaf’s own measurements, average energy use normally lingers around 3-5 miles per kW-hr.

Level 2 power can be remarkably consistent too. The MT garage’s 208-volt charger has been charging at a rate of 3.4-3.6 kW-hrs per hour. By comparison, from the statistics we’ve gathered so far, public ChargePoint stations rated for 240 volts can swing from 3.0-3.8 kW-hrs per hour though they mostly hover near 3.7 in the majority of our encounters, proving to be a valuable ally when you want to top off the battery. And in keeping with the slow-drip analogy above, 3.7 kW-hrs per hour would be about 14 fluid ounces of gasoline. A pint of the wholesome milk you consumed (or avoided) during grade school is 16 fluid ounces.

Did I mention I paid a visit to a DC fast charger? A solitary Level 3 public charger (generically meaning 300-500 volts) sits in a parking lot in Vacaville, California, about 50 miles northeast of San Francisco. In an advance scouting run, I took a closer look without the Leaf, and found that the CHAdeMO charger had been turned off since we last saw it on a Mitsubishi i drive. The taped-up paper sign said Northern California utility provider Pacific Gas and Electric Company was working on “appropriate certification,” and we’re told that regulatory red tape is the lone reason the DC quick charger is unavailable to the public (courtesy of Mitsubishi’s David Patterson). Because the charger was sourced from the Tokyo Electric Power Company, it doesn’t meet certain rules in the U.S. to allow mass utilization. So we’ve yet to find an operating fast-charge dispenser for our car’s optional DC plug ($700 for SL trim, included with SL-e), but we haven’t given up yet.

*Photography by Michael Shaffer, DC quick charger photo by Benson Kong

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