- Researchers tested EVs in cold, moderate and hot conditions
- Results reflect compromised EV range in extreme weather
- EV shoppers in extreme climates should expect shorter range
A new report by AAA finds that electric vehicle (EV) range is significantly impacted by extreme weather. At chilly temperatures of 20 degrees Fahrenheit, the average range for three EVs tested dropped by 57 percent. In hot temperatures of 95 F, the average range was 33 percent shy of the average range at a moderate 75 F. Car shoppers who live in extreme climates and are considering an EV should expect a shorter overall driving range than Environmental Protection Agency (EPA) estimates suggest when the weather is harsh, whether that means very cold or very hot temperatures.
AAA does not identify the models tested, but it did provide an explanation of the testing procedure and a benchmark for range performance. Each vehicle was subjected to three tests on a dynometer (which is a treadmill equivalent for cars) in a temperature-controlled room. Researchers used a standard EPA driving cycle that simulates real-world driving, running each fully charged vehicle until its batteries were exhausted at three different temperatures. At a moderate temperature of 75 F, average range among the three was 105 miles.
The report reflects a drop to just 43 miles in its cold-weather test. Several factors contribute to weaker electric vehicle range in the winter. First, EV batteries operate most efficiently in moderate temperatures. In extreme conditions, batteries deliver less energy. Warming the vehicle cabin for driver and passenger comfort also impacts range. EVs use energy from the batteries, which could otherwise be used to power the vehicle’s electric-drive motor, to control cabin temperature. In conventional vehicles, cabin heat is converted from heat wasted by the engine, which has a less significant impact.
Both of these factors impact range at higher temperatures, too. At 95 F, the three EVs in AAA’s test averaged 69 miles.
But outside temperature, along with cabin heat and air conditioning, impact fuel economy in conventional vehicles, too. Because gasoline- and diesel-powered cars and trucks typically offer three to four times the range of EVs, these drivers don’t need to make special considerations for extreme weather.
AAA did not identify which three EVs it included in its test, so we can’t be sure how its average range of 105 miles compares to EPA-rated ranges for specific models. It appears, however, that AAA achieved a significantly greater range — perhaps 25 percent greater — at moderate temperatures, since most popular EVs have an EPA-rated range of about 80 miles.
In fact, many EV drivers report greater-than-expected range in moderate temperatures. So while car shoppers in extreme temperatures should expect a reduced range, those in more temperate climates may exceed EPA range estimates.
What it means to you: Shopping for an electric vehicle? Consider the climate in your area and the distances that your driving schedule demands.