Do EVs work as well in cold weather?

If you’re wondering whether freezing temperatures affect an electric vehicle’s battery the answer is yes. 

But experts also say there are ways to mitigate the effects of extreme cold. Like gas vehicles, an electric vehicle in freezing temperatures requires a few changes to your routine.

According to a study published recently by Recurrent, a Seattle company that tests and analyzes electric vehicles, EVs tend to lose a significant amount of range in cold temperatures. That means the battery won’t get you as far as it would under ideal circumstances. Depending on the distance you plan to drive that may mean an extra charging stop.

The company, which studied more than 10,000 cars in the U.S., analyzed 20 popular EV models, and found that in freezing conditions the electric vehicles only maintained 70 per cent of their range on average. The data collected “include all real-world variables, such as uneven terrain, variable driving speeds and uses, and calendar aging in vehicle batteries.”

79 per cent of range

The study revealed the EV models “average 79 per cent of their range in freezing temperatures compared to ideal conditions, but each model performs differently based on available features and battery chemistry.” However, every modern EV studied can deliver 160+ kilometres of range, even in extreme cold.

Consumer Reports conducted its own tests and found the cold weather can impact EVs even before the temperature drops to freezing. Their tests found that the range starts to drop at 4 C. Cold weather, it found, can drain about 25 per cent of range when driving at higher speeds of just over 110 km/h.

"There’s validity to the concern that you are going to lose some range in the really cold weather," Cara Clairman, president and CEO of Plug'n Drive, a Canadian non-profit organization that seeks to answer consumer questions about electric vehicles, told CBC recently.

But Clairman said most drivers on a typical day aren’t driving anywhere near the top of their vehicle’s range, which for most is between 400 and 500 kilometres on a full charge.

"Let's say you might lose 20 per cent. That's only an issue for you if that particular day you're driving 350 kilometres," she said. "It's probably not an issue for most people."

Why does extreme cold affect EVs?

Winter range loss occurs for a few reasons, but the Recurrent study highlights two main factors: 

• Chemical and physical reactions in the battery occur more slowly in cold temperatures. Cold temperatures inhibit chemical reactions and act as resistance that slows down the physical processes. This reduces the EVs available power.
• The major reason is due to cabin heating to keep the driver and passengers warm. An EV has a more efficient motor than a gas-powered vehicle. That means electric cars have to draw energy from the battery to produce cabin heat as opposed to the internal combustion engine that pumps “waste heat” directly into the car to warm up occupants. 

It should be noted, however, any range loss from winter weather is temporary and there is no long term harm to an EV’s battery.

How EV owners can offset winter range loss

1. Prepare for longer charge times To protect the high voltage battery, many cars limit the charging voltage when the battery is cold. Regular charge speed returns when the battery has warmed up. In many newer EVs, if you use the in-car navigation system to head to a charger, the car will condition the battery for optimal charging temperature, meaning your charge time may be reduced. 
2. ‘Precondition’ your vehicle As much as possible, warm up your car while it’s still charging. This is called preconditioning. It is available in most EVs by using your phone’s app or by setting up a departure time. Some vehicles also offer a “winter weather” package designed to keep battery temperatures in an ideal zone so they are always ready when you start to drive.
3. Turn down the cabin heaterOnce the car is warm and you’re driving, use seat warmers, a heated steering wheel, and turn down the cabin heater. These features use less energy and provide targeted heat, giving you more battery to travel.
4. Turn down regenerative braking On slippery roads, you will want to be able to engage your brakes more. Regenerative braking may also be limited by your battery management system if the battery is cold.
5. Store EVs plugged in with a maximum charge setting of 70 or 80%. That way, the car can pull energy from the wall to keep warm, rather than the battery. Otherwise, you may return to a lower battery capacity than expected.

Heat pumps can help

If you buy an EV with a heat pump, you won’t have to worry about reduced range in the winter as much because they are more energy efficient for cabin heating and cooling, the Recurrent report notes.

But that advantage will change depending on the weather. At 0 C a traditional EV could have a range loss of 25 per cent, while one with a heat pump would lose only 5.9 per cent. However, as the temperature approaches -7 C, heat pumps may only have an advantage of about three to 15 per cent, it says.
-    With files from CBC News

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