Do Electric Vehicles Consume More Power at High Speed or Low Speed?
4 Answers
Electric vehicles consume more power at high speed. Electric vehicles are more energy-efficient at low speed and consume more power at high speed: The working efficiency of an electric motor in a pure electric vehicle is almost unaffected by its rotation speed, and it does not lose energy through a transmission. Therefore, pure electric vehicles are very energy-efficient at low speeds. When running at high speed, although the motor efficiency can be maintained at 80%-90%, air resistance increases with the square of the speed. The higher the speed, the greater the air resistance the electric vehicle needs to overcome, resulting in significantly higher power consumption at high speeds compared to low speeds. Pure electric vehicles can recover kinetic energy at low speed: Another technology that makes pure electric vehicles energy-efficient at low speed is kinetic energy recovery. During frequent deceleration at low speeds, the vehicle recovers energy each time and transmits it back to the battery. The most energy-efficient speed for a pure electric vehicle is low speed, with an energy efficiency of 80%-90%. Combined with 20% from kinetic energy recovery, the energy-saving effect is surprisingly good.
Electric cars consume more power at high speeds. The physics explanation is simple: as speed increases, wind resistance rises dramatically. When speed increases from 60 km/h to 120 km/h, wind resistance nearly quadruples, and the electric motor must output more energy to overcome it. At lower speeds around 40 km/h, wind resistance is much smaller, with rolling resistance and start-stop effects being the main factors. Although the initial acceleration consumes high power, it is brief. On average, high-speed driving demands more overall energy. From my experience, electric cars average around 15 kWh/100 km in city driving, while highway driving easily exceeds 20 kWh/100 km. My advice is to maintain a speed between 80 to 100 km/h—avoid speeding but also don’t drive too slowly. Additionally, ensure proper tire pressure and avoid excessive air conditioning to maximize efficiency and range.
As someone who has driven an electric vehicle for three years, highway driving definitely consumes battery much faster. In urban low-speed driving, frequent starts and stops do use more electricity, such as the high instantaneous peak when starting at a red light, but overall, due to the slower speed and lower wind resistance, the electricity consumption is still manageable. On the highway, once you exceed 100 km/h, the battery drains like a faucet that hasn't been turned off tightly. Once on a long-distance highway trip at 110 km/h, I used 25% more electricity per 100 km, noticeably increasing the number of charging stops. At low speeds, regenerative braking can recover energy, but this advantage diminishes at high speeds. It's advisable to maintain a steady cruising speed around 90 km/h on the highway, with smooth acceleration and deceleration, avoiding sudden braking or hard acceleration, which ensures both safety and extends the driving range.
Electric vehicles consume more power at high speeds. From a cost perspective, electricity expenses are definitely higher on highways due to greater resistance and higher energy consumption, resulting in significantly more power consumption over the same distance. Although frequent starts and stops in urban areas lead to higher instantaneous power usage, the average power consumption is lower, and regenerative braking can recover some energy, making it more cost-effective in the long run. My family uses an electric vehicle and plans routes to avoid highways whenever possible, keeping the speed around 60 km/h to save power and extend battery life. Factors affecting this include temperature—highway driving in winter drains the battery faster, so remember to check tire pressure regularly, as low pressure or using air conditioning can make things worse. Overall, driving an electric vehicle at slower speeds is more economical.
