Jens Kratholm, an ophthalmologist who lives in the town of Narvik, some 136 miles north of the Arctic Circle. The average temperature there is 39 degrees Fahrenheit. If electric car batteries fare poorly in chilly temps, Narvik would be a bad place to own a Tesla. And yet, Kratholm owns a Tesla Model S. He also owns six Tesla Roadsters. To Kratholm, Tesla's biggest selling point is its performance in cold weather.