How does hot weather affect electric cars?

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As temperatures soar, hot weather can have a significant impact on electric cars — affecting both their range and battery health. We explain why and what you can do about it.

Electric vehicles (EVs) are more prone to overheating than conventional cars for two main reasons. One is that batteries in electric vehicles underperform in hot weather because higher temperatures cause electrons in the battery to move slower, reducing the amount of power available.

The second is that EVs don’t rely on a combustion engine to disperse heat. And that lack of an internal combustion engine means there's no efficient way for the battery to cool down, which can cause it to overheat and reduce its range.

Lithium-ion and lithium-iron batteries perform best at certain temperatures, ideally between 68 to 86 degrees Fahrenheit. HERE estimates that EV range can drop by 15% when temperatures start to go above 95 degrees Fahrenheit. So avoid traveling long distances during very high temperatures and always try to park your vehicle in the shade.

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Another way to combat overheating is by monitoring your level of charge before you set out. When batteries are too low, they can heat up quickly and be more prone to overheating or discharging rapidly. That’s why it’s important to make sure an electric vehicle has been charged adequately before driving in hot weather — a fully-charged battery will retain its cool temperature for longer and enable your electric car to hold its range better.

And it's not just running a vehicle that can cause temperatures to rise. The process of charging itself can also cause batteries to overheat. Many electric vehicles have built-in systems that monitor the temperature of the EV battery. If the system detects that the battery is getting too hot while charging, it will automatically slow down the rate at which the car charges — this is also known as "thermal throttling".

By reducing the charging speed, the system reduces the amount of heat generated, helping to keep the battery at a safe temperature. So try charging your vehicle during cooler temperatures and not during the hottest part of the day.

A short spell in the sun shouldn't impact your car too much but prolonged exposure can mean that the battery won't last as long as it should. But don't worry, many electric vehicles are equipped with thermal management systems to help maintain the optimum battery temperature and mitigate some of these effects.