Study: Icy Temps Kill Electric Vehicle Range

DENVER (Feb. 18, 2019) – As temperatures fall across Colorado, electric vehicle owners take note: Your car simply will not be able to travel as far as it does normally. That's the takeaway from a new report from AAA, which found that cold weather can sap electric vehicle batteries of nearly half of their driving range. 

Per AAA research, when the mercury dips to 20°F and the car's heater is engaged, an electric vehicle's average driving range plummets 41 percent. That means that for every 100 miles of combined urban/highway driving, the range at 20°F would be reduced to 59 miles. To minimize the chance of a dead battery, electric vehicle owners should make a habit of checking the forecast and planning ahead for this range reduction and the need to charge more frequently.

"As electric vehicles increase in popularity, it's important to remember how they differ from gas-powered cars," said AAA Colorado spokesman Skyler McKinley. "Colorado isn't California – our temperatures fluctuate here, and often dramatically. That doesn't mean you shouldn't buy an electric car, it just means you should understand their limitations when cold weather comes around."

It's not just the cold. AAA's research also found that when outside temperatures heat up to 95°F and air-conditioning is switched on, driving range decreases by 17 percent. While extreme temperatures play a role in range reduction, the real culprit is the use of heating and air-conditioning systems – especially the heater. 

It follows that an electric vehicle with a compromised driving range will require charging more often, increasing the cost to operate the vehicle. AAA's research found that the use of heat when it's 20°F outside adds nearly $25 more for every 1,000 miles when compared to the cost of combined urban and highway driving at 75°F.

AAA tested five electric vehicles, all with a minimum EPA estimated driving range of 100 miles, in partnership with the Automotive Club of Southern California's Automotive Research Center. Real-world conditions were simulated using a dynamometer, essentially a treadmill for cars, in a closed testing cell where ambient temperature could be closely controlled. To determine the effects on driving range, scenarios for cold and hot weather conditions – both when using the heating/air-conditioning and not – were compared to those of driving with an outside temperature of 75°F.

"It's clear that electric vehicles thrive in more moderate climates. Here's the problem: Most Americans live in an area where temperatures fluctuate," McKinley said. "The good news is that automakers are continually making advances to improve range. For now, though, electric vehicle drivers have a responsibility to plan ahead during both cold and hot weather."

Simple Precautions
If you drive an electric vehicle, it's easy to offset potential temperature-related reductions in driving range:

• Plan ahead. When drivers are aware of the weather conditions before heading out, they can plan ahead for more frequent charging stops. Drivers can find charging stations through AAA's mobile app. 
• Make time to "pre-heat" or cool down the inside of the vehicle while still connected to the charger. This will reduce the demand on the vehicle's battery to regulate cabin temperature at the onset of driving. 
• If possible, park inside a garage to stabilize cabin temperature. 

Methodology

AAA conducted primary research in partnership with the Automotive Club of Southern California's Automotive Research Center (ARC) in Los Angeles to understand impacts of ambient temperature on electric vehicle driving range with and without the use of the heating and cooling system. The vehicles were tested using the ARC's climate-controlled test cell and state-of-the-art chassis dynamometer and data logging equipment.

Test vehicles were selected using a pre-determined set of criteria such as availability for sale throughout the United States with a minimum EPA estimated driving range of 100 miles. One vehicle per manufacturer was tested to prevent overrepresentation of a single brand. Additional information on methodology can be found in the full report here.

About AAA Colorado

More than 685,000 members strong, AAA Colorado is the state's most-trusted advocate for the safety and security of all travelers. As North America's largest motoring and leisure travel organization, AAA provides more than 58 million members with travel, insurance, financial, and automotive-related services - as well as member-exclusive savings. For more information, visit AAA.com.