Cold Weather Kills Electric Car Range

California resident Sam Miller-Christiansen just loves his 2014 Chevy Volt, which he calls “my little Zen garden on wheels.” But he’s “always longed for better electric range” than the 38 miles his car achieves on a good day. For 2016, Chevrolet listened to the feverish testimony of Volt owners and jumped that battery mileage to 50.

Range is a huge issue with EV owners, and for very good reasons. The Volt has the gas engine in reserve, but 100 miles is the standard top end for battery electrics. And that’s only under optimal conditions; bad weather makes the range much worse.

A study published in Environmental Science and Technology (EST) looks at the range-and-weather equation, and reports, based on driver testimony, that cold days (using the heater) or very hot ones (air conditioning) can reduce range up to 40 percent. Remember that gas cars generate their own electricity for accessories like that; in electrics, everything drains the battery. Also, batteries simply aren’t as efficient in extreme weather (especially if they lack pack heating and/or cooling).

And I’ve seen much the same in winter EV driving — the 100-mile car becomes the 60-mile car. A Volt I drove during a New England winter went 28 miles before switching to the gas engine, which isn’t bad — Nissan Leaf and Mitsubishi i-MiEV cars I drove did worse under frigid conditions.

I like heat in the winter (and air conditioning in the summer), which is one reason my results are worse than average. Patrick Wang, a San Francisco Volt owner, told me that 40-degree weather reduced his range modestly to 34 miles, and he compensates by pre-warming the car while it’s plugged in at home, then setting the heater to low.

Carbon dioxide emissions per mile go up in colder climates, worsening the environmental equation. (Graphic: Environmental Science and Technology)

EST’s research suggests that that in a city with a moderate climate, such as San Francisco, the median range for a Nissan Leaf battery electric is around 76 miles, and it’s above 70 miles more than 99 percent of the time. In a super-hot city like Phoenix, it can drop to 49 miles on the worst day of the year, while in super-cold Rochester, Minnesota, a 36 percent range drop was observed. Even within a big state like California, there can be energy-consumption-per-mile variations of 18 percent because of differences in weather.

Range (in all weather) is king, and that’s why the Tesla Model S’s 265 miles is so prized. And it’s also why the Volt’s 2016 improvement is so welcome. “I said that if they could improve the overall EV range, it would make one of my favorite cars even better,” Miller-Christiansen said. “To my amazement, they’ve done it.”

Jeremy Michalek of Carnegie Mellon University, co-author of the EST study, told me, “Climate is one extra factor that electric car buyers should consider depending on where they live. It’s a challenge for extending the electric car’s territory in some parts of the country, because buyers may experience certain days when the range is quite a bit less than rated. In California, where most of the sales are happening now, even on the worst days of the year the range is still mostly good.”

Michalek points out that Californians’ environmental equation is also bettered by the fact that the state gets most of its electricity from clean sources. A Union of Concerned Scientists report found, encouragingly, that 60 percent of the U.S. population lives in regions where, all factors considered, the battery electrics emit fewer greenhouse gases than a Toyota Prius hybrid. Climate Central also investigated, concluding that electric cars are the best option for the climate in 16 states.

But these are moving targets. The electric grid is getting cleaner, and as it does the EV’s environmental scorecard improves in most of the country.

In the meantime, there are also ways you can minimize cold-weather problems in an electric vehicle. Green Car Reports offers several helpful ideas, like preconditioning your battery and cabin (i.e., warming up while the car is still plugged in), using the car's lower-power mode, or just bundling up in warm clothes.