Cold may slash electric car range

DETROIT — Cold temperatures can sap electric car batteries, temporarily reducing their range by more than 40 percent when interior heaters are used, a new study found.

The study of five electric vehicles by AAA also found that high temperatures can cut into battery range, but not nearly as much as the cold. The range returns to normal in more comfortable temperatures.

Many owners discovered the range limitations last week when much of the country was in the grips of a polar vortex. Owners of vehicles made by manufacturers including Tesla, the top-selling electric vehicle company in the U.S., complained on social media about reduced range and frozen door handles during the cold snap.

“As long as drivers understand that there are limitations when operating electric vehicles in more extreme climates, they are less likely to be caught off guard by an unexpected drop in driving range,” Greg Brannon, AAA’S director of automotive engineering, said in a statement.

The automobile club tested five cars at 20 degrees and 95 degrees, comparing the range to when they were tested at 75 degrees Fahrenheit, according to a report on the study.

At 20 degrees, the average driving range fell by 12 percent when the car’s cabin heater was not used. When the heater was turned on, the range dropped by 41 percent, AAA said.

For example, AAA’S testers determined that a 2017 Tesla Model S 75D range when fully charged at 75 degrees was 239 miles, but it fell 91 miles, or 38 percent, at 20 degrees.

In a statement, Tesla disputed the AAA results. The company said that based on data collected from its cars on the road, “the average Model S customer doesn’t experience anywhere near that decrease in range.” The company said the range dropped by roughly 1 percent at 95 degrees, but it would not release a percentage for cold weather.

AAA said it followed test procedures drawn up by SAE, an auto engineering trade group.