AAA Study Finds Cold Weather Causes Substantial Drop in EV Range

New research from AAA finds that when the outside temperature hits 20°F (-6.7 ˚C) and the HVAC system is used to heat the inside of an electric vehicle, the average driving range is decreased by 41%. This means for every 100 miles of combined urban/highway driving, the range at 20°F would be reduced to 59 miles.

AAA conducted primary research to understand the effects of ambient temperature on the range and equivalent fuel economy of five battery electric vehicles (BEVs) sold throughout the United States: the BMW i3, Chevrolet Bolt, Nissan LEAF, Tesla Model S 75D and the Volkswagen e-Golf.

Testing was performed according to guidelines established in SAE International standard J1634, Battery Electric Vehicle Energy Consumption and Range Test Procedure. Evaluated ambient temperatures included 20°F, 75°F and 95°F.

Key findings included:

• In isolation, hot and cold ambient temperatures resulted in modest reductions of driving range and equivalent fuel economy. Driving range and equivalent fuel economy reductions slightly differ due to the temperature dependency of both the recharge allocation factor (RAF) and battery discharge capacity.
  • On average, an ambient temperature of 20°F resulted in a 12 percent decrease of combined driving range and a 9 percent decrease of combined equivalent fuel economy (when compared to testing conducted at 75°F).
  • On average, an ambient temperature of 95°F resulted in a 4 percent decrease of combined driving range and a 5 percent decrease of combined equivalent fuel economy (when compared to testing conducted at 75°F).
• HVAC use results in significant reductions of driving range and equivalent fuel economy.
  • On average, HVAC use at 20°F resulted in a 41 percent decrease of combined driving range and a 39 percent decrease of combined equivalent fuel economy (when compared to testing conducted at 75°F).
  • On average, an ambient temperature of 95°F resulted in a 17 percent decrease of combined driving range and an 18 percent decrease of combined equivalent fuel economy (when compared to testing conducted at 75°F).
• Depending on ambient temperature, HVAC use results in a significant monetary cost increase. For example, the study found that the use of heat when it’s 20°F outside adds almost $25 more for every 1,000 miles when compared to the cost of combined urban and highway driving at 75°F.

Thus, when colder temperatures hit, AAA urges electric vehicle owners to be aware of a reduction in range and the need to charge more often to minimize the chance of being stranded by a dead battery.