Data from Geotab indicates that driving speed significantly impacts electric vehicle (EV) range loss more than summer heat.

While high temperatures affect range, the aerodynamic drag from increased speeds is a more substantial factor in range reduction, according to the connected vehicle solutions provider.

Geotab said it analysed anonymised telematics data from more than three million trips.

The study focused on how temperature and speed influence energy use in light-duty EVs, such as sedans and cargo vans.

It found that at speeds between 50mph and 80mph (80.4km/h- 128.7km/h) in temperatures of 30°C, aerodynamic drag has a more pronounced effect on range than air conditioning. 

For instance, a 65kWh electric van travelling at 50mph in 30°C with air conditioning on has a typical range of 143 miles.  

Increasing the speed to 60mph reduces the range to 121 miles.

At 70mph, the range drops to 103 miles, and at 80mph, it falls further to 88 miles, marking a 39% decrease in range between 50mph and 80mph. 

Electric sedans, being more aerodynamic, show a similar pattern, Geotab says.  

At 50mph in 30°C, the range is 277 miles, reducing to 251 miles at 60mph, 226 miles at 70mph, and 200 miles at 80mph, a 28% decline from the most efficient speed. 

The drop in range is attributed to physics, as higher speeds increase aerodynamic drag, which grows with the square of speed.  

It requires significantly more energy to overcome than what is used by air conditioning systems. 

At lower speeds, the impact of heat is more noticeable due to minimal drag, making the constant draw from air conditioning more apparent.  

However, at higher speeds, the energy needed to maintain speed overshadows the temperature’s effect. 

Geotab’s sustainability senior manager Charlotte Argue said: “Drivers tend to worry about using the aircon in hot weather, but our data shows that your right foot can make the biggest difference, particularly at high speeds. Just slowing down by 10mph or 15mph can extend your range by 20%–30%, depending on the vehicle. 

“Modern EVs have increasingly large batteries, and many can comfortably handle most daily driving – including fleet routes – on a single charge. But range, on EVs or ICE vehicles, will always vary with real-world conditions: temperature, topography, traffic, and yes, speed.” 

Geotab suggests several strategies to optimise EV range without sacrificing comfort.  

These include reducing speed, preconditioning the cabin while plugged into grid power, efficiently using air-conditioning, avoiding aggressive driving, parking in the shade, and avoiding fast charging during extreme heat.