Road tests of some of the most popular electric vehicle (EV) models have found they lose 14 to 39 per cent of their marketed range in winter conditions, according to the Canadian Automobile Association (CAA).

Fourteen cars representing over two-thirds of EV sales in Canada were driven from Ottawa to Mont Tremblant, over 150 kilometres, in sub-zero temperatures ranging from -7 C to -15 C to conduct the testing. CAA examined how far the EVs could drive before the batteries died, and how much range was added with a 15-minute charge using a fast charger.

Chevrolet’s Silverado EV and the Polestar 2 lost the least range from their stated figure – both at 14 per cent. Volvo’s XC40 Recharge fared the worst, losing 39 per cent of the expected range from the cold. The Toyota bZ4X, Hyundai IONIQ 5 and Ford F-150 Lightning were poor performers as well.

"The vast difference in results highlight the importance of truth in advertising when it comes to EV range, and of comparing numbers if winter performance matters to you," Ian Jack, vice-president of public affairs at CAA, said in a release.

Charging also varied from as much as 205 kilometres of range added in 15 minutes for the Tesla Model 3, to as little as 35 kilometres for the Kia Niro EV.

The impact of frigid temperatures highlight a survey from CAA that found over two-thirds of Canadians said the lower winter driving range is a top barrier to buying the vehicles. A similar number of EV drivers said they have experienced lower battery range in very cold weather.

As a result, 53 per cent of EV drivers said they preferred to take a gas-powered vehicle on long trips in extremely cold weather.

Why EVs lose range in the cold

The findings add more backing to studies that have shown winter weather saps EV batteries of range and lengthens the time for a charge. Seattle-based Recurrent, a company that collects data on used EVs, found in its winter road tests of 18 popular EV models that battery range was cut by 30 per cent on average.

Recurrent explained the cold weather slows chemical reactions in batteries, reducing available power. Heating also plays a critical role. An EV has to expend energy from the battery to warm the car versus a gas-powered model that taps into waste heat from the internal combustion engine.

Freezing conditions do not inflict long-term damage to an EV’s battery, Recurrent added. 

CAA also explored the importance of charging, a matter that does not receive as much attention as limited battery range in winter but is also an issue. The Association’s survey of EV drivers found 40 per cent identified significantly slower charging in extreme cold weather as a problem.

How to stretch EV battery life in winter

To get as much charge from an EV battery as possible, CAA laid out four tips:

• Warm the cabin while the vehicle is plugged in before driving;
• sweep away snow and ice to reduce weight and drag;
• use heated seats rather than cabin heaters to save battery life; and
• park the EV indoors or in a sunny place to keep the battery warmer.

Jack also urges the creation of a Canadian standardized labelling system for EVs that “includes winter driving performance, rather than just a single average." As only a single average in Canada is published, consumers do not have an accurate idea of winter range, CAA said.