Why do electric cars suck in cold weather?

In hindsight, it’s not surprising the Mitsubishi MiEV EV I drove barely made it to 50 miles rather than its rated 62 miles (100 km). It was a dark and chilly if not stormy early December night and that killed the range. When you drive an EV, “your mileage may vary” includes cold weather as well as hard acceleration and late braking. As temperatures dip below freezing, you could lose 25% of your electric vehicle’s precious range. Batteries are less efficient in cold weather, they don’t regenerate as well, and electric heating for the cabin, seats, and windows drains your range, too.

The same thing happened when I drove a Tesla Model S. With the 85 kWh battery, the Tesla is good for around 250 miles. During the afternoon with temperatures above freezing, the discharge rate indicated I wasn’t far off from that kind of efficiency. Driving at night as temperatures fell into the 20s (0C to -5C), I found the range fell noticeably faster than the distance gauge suggested at the start of the trip.

None of this should be surprising. The 12-volt batteries on mainstream cars are prone to failure in the first cold weeks of winter. A battery is a chemical reaction that gives off electrons, or power. When it’s cold, the reaction slows down in both directions, discharging and charging. See, there was a reason to pay attention in chemistry class. You can keep a chemical reaction going by applying heat, which is one way to get more energy out of a battery — but that can be a complex equation, if the energy to heat the battery comes from the battery itself.