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How Do Cold and Speed Affect EV Driving Range?How Do Cold and Speed Affect EV Driving Range?

Drivers need to know what to expect from EVs in winter driving.

Dan Carney, Senior Editor

February 7, 2023

2 Min Read
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Cold-weather driving like this can slash EV driving range by half.Image courtesy of Volvo

Drivers who are familiar with the characteristics of combustion-powered vehicles need to have a clear idea of what to expect from EVs for them to comfortably make the switch.

That’s why telematics specialist Geotab has compiled data from 3 million fleet vehicle trips and more than half a million hours of driving to analyze EV driving range in various weather conditions. The study also compared the performance of boxy delivery vans with slipperier sedans to observe the effect of aerodynamic drag due to higher speeds on the driving range.

Looking at the data, Geotab found that actual driving range is about 15 percent better than the rated range when driving at an optimal 68 degrees. On the other hand, extremely cold weather can slash the range by as much as 50 percent. This is mostly due to the energy required to keep the cabin and batteries at a comfortable temperature.

Speed also has a dramatic impact, though Geotab found that ideal speeds are too slow to be practical for highway driving. For around-town fleet drivers, however, it could be beneficial to prefer surface streets to highways for improved range.

That’s because aerodynamic drag increases proportionally to the square of the speed, so if you double the speed, the drag goes up by a factor of four.

During highway driving, it is crucial to avoid speeding to conserve range, especially for larger vehicles like boxy delivery vans. For surface street driving around town, aerodynamic drag has less effect, so temperature becomes the overriding factor, and mitigating the impact of temperature will preserve energy for driving range.

“Backed by real-world EV data, the analysis is intended to be used as a resource to help educate users on factors that impact EV range and build awareness of strategies to optimize EV deployment,” explained Charlotte Argue, Senior Manager of Fleet Electrification at Geotab.

At 68F the sedan’s maximum range is achieved at about 19 mph. The need to shorten the length of time running heaters makes the ideal speed at 32 degrees 37 mph because the extra energy lost to aerodynamic drag is saved in a shorter time of heater use up to that speed. Faster speeds use the heaters for even less time, but the aerodynamic drag losses overwhelm the savings.

The van has more drag, so peak efficiency occurs at slower speeds than for the car. At 68 degrees, the most efficient speed is 16 mph, which is pretty similar to the sedan. But at freezing temperatures, the optimal speed is impractically slow at approximately 25 mph.

This means that even avoiding highways will not let drivers achieve the rated driving range in their EVs, and it is important that prospective EV buyers understand and plan for this reality when switching from combustion-powered vehicles.

 

About the Author

Dan Carney

Senior Editor, Design News

Dan’s coverage of the auto industry over three decades has taken him to the racetracks, automotive engineering centers, vehicle simulators, wind tunnels, and crash-test labs of the world.

A member of the North American Car, Truck, and Utility of the Year jury, Dan also contributes car reviews to Popular Science magazine, serves on the International Engine of the Year jury, and has judged the collegiate Formula SAE competition.

Dan is a winner of the International Motor Press Association's Ken Purdy Award for automotive writing, as well as the National Motorsports Press Association's award for magazine writing and the Washington Automotive Press Association's Golden Quill award.

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He has held a Sports Car Club of America racing license since 1991, is an SCCA National race winner, two-time SCCA Runoffs competitor in Formula F, and an Old Dominion Region Driver of the Year award winner. Co-drove a Ford Focus 1.0-liter EcoBoost to 16 Federation Internationale de l’Automobile-accredited world speed records over distances from just under 1km to over 4,104km at the CERAM test circuit in Mortefontaine, France.

He was also a longtime contributor to the Society of Automotive Engineers' Automotive Engineering International magazine.

He specializes in analyzing technical developments, particularly in the areas of motorsports, efficiency, and safety.

He has been published in The New York Times, NBC News, Motor Trend, Popular Mechanics, The Washington Post, Hagerty, AutoTrader.com, Maxim, RaceCar Engineering, AutoWeek, Virginia Living, and others.

Dan has authored books on the Honda S2000 and Dodge Viper sports cars and contributed automotive content to the consumer finance book, Fight For Your Money.

He is a member and past president of the Washington Automotive Press Association and is a member of the Society of Automotive Engineers

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