AAA Study: Extreme Cold Has Chilling Effect on EV Range

By Matt Schmitz  on March 28, 2014

When it comes to all-electric vehicles, the primary source of apprehension for most would-be buyers is range, and logically so. After all, once your EV's battery runs out of juice, unless you happen to be pulling into a charging station at that very moment, that's as far as you're going — at least until the tow truck shows up. While good planning can prevent that scenario, EV drivers must also account for the sometimes-dramatic swings in range caused by varying weather conditions, especially extreme cold.

A Winter in the Nissan Leaf

A new study released this month by AAA found that EV range can be reduced by as much as 57 percent based on the outside temperature. At the AAA Automotive Research Center in Southern California, researchers conducted a simulation to measure the driving range of three all-electric vehicles in cold, moderate and hot weather, and temperature played a major role in driving range for all three.

According to AAA, the average EV battery range was 105 miles at 75 degrees, but dropped to 43 miles when the temperature was reduced to 20 degrees. By comparison, 95-degree temperatures reduced battery life significantly less to 69 miles, a 34 percent dip. Tests were performed between December 2013 and January 2014, with each vehicle completing a driving cycle starting with a full charge under all three temperature conditions until their batteries were fully depleted, following standard procedures of the EPA and the Department of Energy.

The bottom line, according to AAA, is that buyers of EVs must be aware of their limitations as well as their strengths, in varying situations. "EVs provide owners with many benefits, but every motorist needs to be aware of conditions that can impact vehicle driving range," AAA said in a statement. "EV drivers need to plan carefully in hot and cold weather."

The news comes as no surprise to us at, as we spent the winter of 2011 observing weather-induced range swings in our long-term Nissan Leaf test car, variations we described at the time as "erratic." With the car fully charged, estimated range was typically between 70 and 80 miles, in line with the EPA's 73-mile number but well below Nissan's "up to" figure of 100 miles. Outside temperatures ranged from the mid-20s to mid-40s for most recorded trips. The longest predicted range and best-observed outcome both came at higher temperatures than the shortest range and worst-observed outcome. We recorded temperature, predicted miles, actual miles, post-trip readouts of miles per kilowatt-hour and average speed, as well as our own accounting of traffic conditions, and no distance, condition or reading correlated consistently with the range.

"The unpredictable range means the Leaf isn't for someone whose commuting needs are closer to the car's limits than ours are," we said at the time. "And it's certainly not a likely choice if you can own only one car." photo by Evan Sears

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News Editor Matt Schmitz is a veteran Chicago journalist indulging his curiosity for all things auto while helping to inform car shoppers.  Email Matt