AAA: Extreme temps significantly degrade electric car ranges ("extreme" = 95 and 20 degrees) [View all]

[Bill USA]

http://usatoday30.usatoday.com/MONEY/usaedition/2014-03-20-AAA-Range-of-electric-cars-cut-by-57--in-cold-weatherUSABrd_ST_U.htm

The range of electric vehicle can be greatly reduced, by up to 57%, depending on the temperature outside, auto club AAA says.

The AAA Automotive Research Center in Southern California found that the average range of an electric car dropped 57% in very cold weather -- at 20 degrees Fahrenheit -- and by 33% in extreme heat, a temperature of 95 degrees.

"We expected degradation in the range of vehicles in both cold and hot climates, but we did not expect the degradation we saw," said Greg Brannon, AAA's director of automotive engineering.

AAA conducted a simulation to measure the driving range of three fully electric vehicles -- a 2013 Nissan Leaf, a 2012 Mitsubishi iMIEV and a 2014 Ford Focus Electric Vehicle -- in cold, moderate and hot weather. It tested the vehicles for city driving to mimic stop-and-go traffic between December and January, fully charging each EV, and then "driving" each on a dynamometer in a climate-controlled room until the battery was fully exhausted.
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since they didn't specify this, I'm guessing in the high temperature test, they didn't have the air conditioning on in the cars. On a 95 degree day, with humans in the car, you can be pretty sure the A/C will be on. Also, testing a car in a lab with the air temperature at 95 degrees does't come close to driving a car in stop and start "rush" hour traffic on a 95 degree day - heated highway. The air temperature just above a highway in the afternoon (as in afternoon 'rush' hour) is significantly hotter than the air temperature reported by the Weather bureau. I'm going to hazard a guess that with A/C on and driving on a highway with traffic and solar heating going on, that range degradation will be considerably higher the 33% AAA reported for 95 degrees.

Obviously, not every day is going to be at least 95 degrees or hotter or 20 degrees or colder but some fraction of the days in a year will meet these criteria. And on [font size="+1"]those[/font] days the range degradation could be very important.