AAA Research Lays Out How Temperature Affects EV Range

Matt Posky
by Matt Posky

While we all know extreme temperatures influence the performance of electric vehicles, there isn’t a wealth of comprehensive studies on the matter. Hoping to impart some knowledge on the subject, the American Automobile Association released a report on Thursday that examines how climate impacts EVs.

AAA offered an abridged version in 2014, when it claimed data from its Automotive Research Center (ARC) showed battery-only driving range can be nearly 60 percent lower in extreme cold and 33 percent lower in extreme heat. However, the new study fine-tunes those numbers while exploring other avenues of how EV performance can suffer.

This time, the motor club federation rounded up electric vehicles for testing (BMW i3, Chevrolet Bolt, Nissan Leaf, Tesla Model S 75D, and Volkswagen e-Golf) and sent them to ARC in Los Angeles, CA. The study found that, on average, electric driving range decreases by 41 percent when outside temps fall to 20 degrees Fahrenheit and climate controls are switched on, versus the 75-degree benchmark. Range also diminished as the mercury rose, albeit not as aggressively. Running the A/C on a 95-degree day only resulted in a 17-percent average loss in total range.

That seems to indicate that EV battery performance has improved since 2014, as all the vehicles used in the last round of tests were from the 2017 model year or newer. But it also shows that colder climates remain a noteworthy obstacle for electric cars.

There are ways to mitigate this. Drivers can tailor their driving habits to maximize range and automakers have begun installing systems that help regulate battery temperatures. Owners can also pre-heat or cool their vehicles before taking it off the charger to reduce the burden the climate system places on the battery. However, none of these remedies come close to solving the problem entirely. Your best defense remains keeping an eye on your current charge status and holding onto the knowledge that extremely cold temperatures will have an impact.

“As long as drivers understand that there are limitations when operating electric vehicles in more extreme climates, they are less likely to be caught off guard by an unexpected drop in driving range,” said Greg Brannon, AAA’s director of automotive engineering and industry relations, in a statement to Automotive Newswhich first shared the study.

While running an EV in extremely cold weather does incur a modest increase in cost to the owner, just like with internal combustion engines, the big problem is being caught out in the elements with severely diminished range. Losing almost half of your expected driving radius when it’s below freezing is not the kind of surprise you want to get on the side of a highway. Thankfully, AAA knows that knowledge is power and is eager to spread the word.

“The research clearly shows that electric vehicles thrive in more moderate climates, except the reality is most Americans live in an area where temperature fluctuates,” said Megan McKernan, manager of the Automotive Club of Southern California’s Automotive Research Center. “Automakers are continually making advances to improve range, but with this information, drivers will be more aware of the impacts varying weather conditions can have on their electric vehicles.”

The full study goes into extreme detail, examining the individual test results of each car and dialing down some of the associated costs, as well. We recommend taking a look at it if you’re interested in purchasing an EV outside the confines of a warm-weather state, orif you’re simply curious about the science behind the data.

[Image: Electrify America]

Matt Posky
Matt Posky

A staunch consumer advocate tracking industry trends and regulation. Before joining TTAC, Matt spent a decade working for marketing and research firms based in NYC. Clients included several of the world’s largest automakers, global tire brands, and aftermarket part suppliers. Dissatisfied with the corporate world and resentful of having to wear suits everyday, he pivoted to writing about cars. Since then, that man has become an ardent supporter of the right-to-repair movement, been interviewed on the auto industry by national radio broadcasts, driven more rental cars than anyone ever should, participated in amateur rallying events, and received the requisite minimum training as sanctioned by the SCCA. Handy with a wrench, Matt grew up surrounded by Detroit auto workers and managed to get a pizza delivery job before he was legally eligible. He later found himself driving box trucks through Manhattan, guaranteeing future sympathy for actual truckers. He continues to conduct research pertaining to the automotive sector as an independent contractor and has since moved back to his native Michigan, closer to where the cars are born. A contrarian, Matt claims to prefer understeer — stating that front and all-wheel drive vehicles cater best to his driving style.

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  • JoDa JoDa on Feb 10, 2019

    Don't know why you call the little goofs "Tree Huggers" when CO2 and H2O (car exhaust) is keeping trees alive. Maybe you should call the environmentalretardists "Tree Killers"...And why are they called "Green"? Shouldn't they be "Brown"?

    • See 1 previous
    • TimK TimK on Feb 10, 2019

      @golden2husky Yes, do educate us all on the inconvenient truthiness of apocalyptic memes. Gaia cannot survive without our help and intervention! To the Batmobile!

  • Art Vandelay Art Vandelay on Feb 10, 2019

    Heat in extreme cold is going to be tough. I know the higher trim Leaf got a heatpump type arrangement to save on energy. The problem with that is that when it gets below 20 or so Heat pumps loose the ability to make much in the way of heat. In the South we have a resistive grid built into the system to compensate. It takes a lot of energy, but it works because its not that cold very often. I'm not sure how you address this up North. Combined with the fact batteries just dont work as well in the cold and this becomes a real issue. The last time I drove the kids Leaf when it was in the teens here I started off at around 55 miles as opposed to the 78 or so it does in warmer weather (both 100 percent). This was thawing and heating it while still plugged in and just running my seat and steering wheel heater (its an S trim so no heatpump...the heater kills the battery).

    • Art Vandelay Art Vandelay on Feb 10, 2019

      I think at the end of the day this may be a bigger hurdle than charging time.

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