With last weekend’s extreme cold, snow and wind swiping across much of the U.S, television news was peppered heavily with images of electric-vehicle owners – most notably those clogging the lanes of the Tesla Supercharger station in the Chicago suburb of Oakbrook – waiting hours or more for them to charge, following a faster-than-expected depletion of battery power.
At that, the coldest air of the season is expected to descend upon much of the eastern United States in the days ahead, and is likely to give electric vehicle owners – especially newbies – fits with regard to energy consumption and charging.
According to Kelley Blue Book, around 1.2 million new EVs were sold in the U.S. during 2023, which means there are a large number of first-timers out there who have never experienced the genre’s unfortunate limitations with regard to icy ambient temperatures.
As has been widely noted, the change in seasons can be especially pronounced for electric-car owners who suffer Old Man Winter’s shivering grip. An electric vehicle’s operating range and its ability to charge tends to diminish considerably when the mercury plunges. This can mean harsh consequences for unprepared EV motorists traversing longer routes on extremely frigid days.
Cold weather testing conducted by the Society of Automotive Engineers (SAE) indicates EVs can lose as much as around 41% of their battery capacity at 20 degrees Fahrenheit. That means for every 100 miles of driving, a given EV’s range at 20°F would be reduced to 59 miles. As many drivers discovered last week, an EV’s range can be even further diminished should the mercury approach or dip below zero, which can make for a white-knuckle ride in terms of range anxiety.
It seems battery chemistry is the culprit here, as lithium ions tend to move more slowly through the liquid electrolyte that produces electricity in cold weather than under ideal conditions. Because it’s essentially a two-way street, icy temperatures also adversely affect an EV’s battery ability to charge. According to the Idaho National Laboratory, an EV’s battery pack takes in 36% less energy at 32°F than when it’s charged for the same amount of time at 77°F.
Frigid environments also hamper an EV’s regenerative braking function, which recovers energy that would otherwise be lost during decelerating or braking and sends it back to the battery.
What’s more, an EV’s diminished range in cold weather is exacerbated when using the vehicle’s climate control system, which is a virtual given when one is driving in bone-chilling conditions. While gasoline engines generate large amounts of heat that can be harvested to warm a car’s interior, an EV must rely 100% on electricity to keep one’s toes toasty.
The AAA found that at 20°F, an EV’s cold weather range will drop by an average of 12% just by switching on the heater. Of note, models equipped with a heat pump that leverages ambient thermal energy to help heat the vehicle, like the Nissan Leaf, Hyundai Kona and Tesla Model Y, don’t lose as much range in freezing weather with the climate control running.
It should be noted that conventionally powered cars and trucks also get fewer mpg while operating in extreme temperatures, but these losses are more profound with EVs and the state of the nation’s public charging network is still lacking, as those Tesla owners in Oak Brook found out last week. At that, energy losses will vary from one model to another, and according to a variety of factors like vehicle speed, use of accessories, driving over hills and the weight of passengers and/or cargo being carried.
Proper planning here is the key to tempering one’s range anxiety once temperatures begin to plunge. EV owners need to anticipate attaining fewer miles on a charge during sizzling hot or icy cold days, and adjust both their driving styles and expectations accordingly. It’s also wise to keep a watchful eye on an EV’s state-of-charge indicator and be aware of where public charging stations are located in case one is needed, with a backup noted if one’s first choice is inoperable or occupied. Smartphone apps and some vehicles’ navigation systems can help greatly in this regard.
Look for DC Fast Charging units that can bring an electric car’s battery back up to 80% of its capacity in 30-45 minutes, depending on the vehicle, though again this would be accomplished much slowly with frosty ambient temperatures. Use them sparingly, however, as an EV battery could suffer ill effects by fast-charging during extreme temperatures, or when the battery is very close to empty or full.
At that, experts suggest EV owners maintain no more than an 80% charge and not let the battery get depleted below 20% to help prevent a loss in capacity down the road. That’s because maxing out to a full charge and/or completely draining the battery places additional stress on it. It’s also prudent to engage an EV’s “eco” or “battery saver” mode when driving, if it’s so equipped, to conserve energy.
It’s best to keep an electric vehicle garaged (and charging) when not in use to help shield it from the elements. If your vehicle has a pre-conditioning feature, engage it—usually via a model’s smartphone app—before hitting the road. This will heat both the interior and the battery pack while the vehicle is plugged into the charger, and will help preserve battery capacity. Some models will warm the battery automatically in cold weather. If you’re away from home, park the car in the sun to keep it a bit warmer.
And as owners who made it through this summer’s sizzling temperatures can attest, an EV’s range will likewise suffer in extremely hot weather. The AAA’s study determined that when outside temperatures hit 95°F and air conditioning is in use, an EV’s range will drop by an average 17%. Without running the A/C, an EV will suffer a 4% range reduction on an extremely hot day.
Like humans, it seems EVs find moderate temperatures at around 70°F to be the most amenable.
