- Summer heatwaves mean temporary reduction in EV range
- They won’t “ruin” your battery, but they can accelerate the degradation (aging) of the battery pack.
- Avoid charging 100% in hot weather if you can
What temperature is considered too hot for an electric car and will the next heat wave damage your electric car and leave you stranded?
The answer is not as sensational as the headlines some people wrote this summer, or the questions that followed.
Just as hot weather puts extra stress on many parts of a gasoline-powered car, Heatwaves likely to cause more wear on EV batteries. But to get a better understanding and bust the misinformation myth, that’s what EVs are all about—wear.
EV batteries can decomposes faster in hot weather. However, they don’t suddenly fail and leave car owners in trouble—though of course the heat can affect the reliability of the power grid or charging stations that car owners rely on.
“I can count on one hand the number of times we’ve seen a vehicle lose range quickly and unexpectedly, and the team has no reason to believe any of those times were due to a single heat wave,” said Garberson, head of growth and research at EV battery health analytics firm Recurrent.
Periodic EV Battery Health
Based on Recurrent data from 20,000 EVs, there are There is no red-limit temperature at which an EV battery “fails,” or at that time, the battery damage suddenly increased rapidly.
To put it bluntly, Temperature won’t damage your EV.
French fries, cigarettes and other bad habits
It’s better to think of EV battery heat exposure as drops in a bucket, or factors that can be likened to the human aging process and bad habits that can accelerate aging, like smoking or using a tanning bed, Garberson says. Prolonged exposure can alter the rate of electrochemical reactions in the battery, ultimately leading to a shorter lifespan — defined as any point where useful range has dropped to the point where the EV can no longer cover, charge, or operate at the expected rate.
So replacing the battery is not an expected cost at a certain mileage, a cost that will suddenly render the car unusable. For example, as Recurrent’s data shows, Tesla Range Decline There was a marked change in the first three years but then it became more stable.
Tesla Model Y Range Decline (via Recurrent)
Tesla Model 3 Range Decline (via Recurrent)
Thanks to their clever liquid cooling system, fast charging often unlikely to affect the recession in Teslas and most other modern electric vehicles. These systems and improved chemistries have eliminated some concerns about rapid degradation.
Some early electric vehicles couldn’t handle the heat, and batteries degraded more quickly from exposure to heat. Most notably, the first years of the Nissan Leaf were affected; a new “lizard” battery chemistry introduced in 2015 solved the problem, and Nissan has since reported that Leaf batteries lasts a long time.
Caring for your electric vehicle in hot weather
However, there are some practical tips for keeping your battery pack safe and cool in hot weather—and some of them apply to other times of the year as well, and are even more effective. Do not charge the battery to 100% unless necessary. And definitely don’t fully charge the battery before parking.
Park in the shade if it is very hot and sunny. Parking on the asphalt in the midday sun will expose your battery, which is usually located under the car, to heat in the worst possible way.
Also, leave the battery half-charged if you have to leave it in the heat, as the battery will be more stable that way. Recurrent noted that if you can set a charge limit (say, 70%), car owners can leave their cars plugged in during hot weather, and the active thermal management can kick in at lower temperatures than normal.
Tesla Model 3 Performance
Don’t be surprised if the range is affected by a heat wave—temporarily.
EVs don’t lose much range in what’s considered very hot weather. That’s because most EV batteries are at their ideal thermal point, right around room temperature—where the car’s climate control system doesn’t have to do much work, either. And their climate systems don’t have to change the temperature of the cabin by that many degrees.
According to Recurrent’s calculations, EVs may lose just 5% of their useful range at 90 degrees, but at 95 degrees they lose 15%, and at 100 degrees the total loss is up to 31%—still less than some owners report when driving in the winter.
To be fair, if your car doesn’t have a heat pump and relies on a resistance heating system not unlike the one inside a toaster or hair dryer, it will take less energy to cool an EV by 20 degrees than it will to heat it up by 20 degrees. Part of the reason is that cooling an EV doesn’t have to counteract the waste heat of an internal combustion engine.
The bottom line is that cold weather doesn’t cause permanent damage to EV batteries like hot weather does, but like high temperatures, it does result in temporary range loss. Be prepared; monitor your battery’s state of charge; and remember that Range estimates are just that and didn’t see the heat wave coming.
