How EVs Calculate Range: Key Factors Explained
At The Torque Team, we’re often asked how EVs calculate range and why the numbers vary even when the battery is fully charged. While it may seem straightforward, range estimation is an advanced process that factors in battery state, terrain, energy usage, weather, and more. Here’s what affects your EV’s projected distance to empty.
Battery State of Charge (SOC)
The starting point for range calculation is the state of charge (SOC). While it sounds like a simple battery percentage reading, SOC is determined by a complex system. The battery management unit (BMS) monitors voltage, current, charge rate, and temperature, and applies algorithms to estimate SOC.
Even this estimate isn’t perfect—errors of up to 15% are common. This margin of error can dramatically reduce the quoted range. A vehicle with a theoretical 500 km range may only show 425 km to protect battery life. Improving SOC accuracy to within 5% can increase the usable range by up to 50 km—same car, better data.
Energy Consumption Rate
Your EV tracks energy consumption through real-time feedback and past driving data. If recent drives involved steep hills or rapid acceleration, the system will assume higher usage ahead and adjust the remaining range downward.
On the other hand, relaxed city driving with fewer demands on the battery can lead to a more generous estimate.
Weather Conditions
External temperature significantly impacts EV performance. Cold weather reduces battery efficiency and increases power demand for heating. Volvo, for example, reports up to 40% range loss at –10°C. Wind resistance and precipitation also affect range, especially at higher speeds.
Terrain and Route Data
Climbing hills drains more energy than cruising on flat ground. Some EVs integrate GPS-based route data to refine their range calculations, especially when you enter a destination into the navigation system. This allows the car to anticipate inclines and adjust the estimate more accurately.
Accessory Use
Air conditioning, heaters, infotainment systems, and even headlights use energy from the same battery that powers the motor. Unlike petrol vehicles, EVs must generate heat independently, often using a heat pump. In hot or cold conditions, these systems draw significant power, reducing your range.
Regenerative Braking
EVs recapture some energy during braking through a process called regenerative braking. When you slow down, the motor switches to generator mode, sending energy back to the battery.
If the car expects lots of braking—such as in stop-start traffic—it may factor in an optimistic range boost.
Final Thoughts
Understanding how EVs calculate range helps you manage expectations and plan trips wisely. While modern range estimates are increasingly accurate, they’re still subject to real-world variables—like driving style, climate, and topography. Treat range estimates as dynamic forecasts, not fixed figures, and you’ll enjoy more confident electric driving.
If you have more questions about EV performance or servicing, contact the experts at The Torque Team today.
