Study confirms EV drivers’ suspicions about their batteries in winter

13 Feb 2019

Image: © teksomolika/

In many of the most common EV cars on the market, repeatable testing has shown they drastically lose range in cold weather.

The concept that lithium-ion batteries are directly affected by extreme temperatures on both ends of the scale is an old one, especially among electric vehicle (EV) drivers who have claimed that their cars’ range is noticeably lower during these times. Now, one of the first large-scale studies of some of the most common EV cars on the market appears to confirm this, with range dropping dramatically in some cases.

According to the study published by the American Automobile Association (AAA), when temperatures dip to around minus six degrees Celsius, the average driving range decreases by 41pc. So, for every 160km of combined urban and motorway driving, the range would be reduced to 95km.

The AAA tested five EVs with a minimum range of 160km including the BMW i3s, Chevrolet Bolt, Nissan Leaf, Tesla Model S 75D and a Volkswagen e-Golf. All of the cars were tested in real-world driving conditions using a treadmill for cars called a dynamometer in a temperature-controlled room.

However, cold weather was not the only factor found to influence an EV’s range – when the temperature was cranked up to 35 degrees Celsius and the car had its air conditioning on, range decreased on average by 17pc. Additionally, an EV with a compromised driving range requires charging more often.

Tesla fights back

In testing, the AAA found that the use of heat when it’s minus six degrees Celsius outside adds almost €22 for every 1,600km when compared with the cost of combined urban and motorway driving at 23 degrees Celsius.

“Automakers are continually making advances to improve range, but with this information drivers will be more aware of the impacts varying weather conditions can have on their electric vehicles,” said Megan McKernan, manager of Automotive Research Center.

Unsurprisingly, the manufacturers involved in this study are refuting the AAA’s findings, with Tesla in particular being the most vocal.

In a statement it said: “Based on real-world data from our fleet, which includes millions of long trips taken by real Model S customers, we know with certainty that, even when using heating and air conditioning, the average Model S customer doesn’t experience anywhere near that decrease in range at 20 degrees Fahrenheit. And the decrease in range at 95 degrees Fahrenheit is roughly 1pc.”

Colm Gorey was a senior journalist with Silicon Republic