EV Gradeability Calculator
An EV Gradeability Calculator is a tool used to determine an electric vehicle’s ability to climb a slope or gradient. It evaluates whether the traction motor, drivetrain, and powertrain configuration can generate sufficient tractive force to overcome gravity, rolling resistance, and aerodynamic drag on an incline. This calculator uses inputs such as vehicle mass, motor torque, gear ratio, wheel radius and drivetrain efficiency to compute the maximum climbable gradient (expressed as %) on a given slope.
Enter the Wheel Radius, Vehicle Mass, Peak Motor Torque, Gear Ratio, Drivetrain Efficiency, Angle of Inclination, and Rolling Resistance Coefficient to determine whether the EV can handle specific gradients.
Result
Maximum Gradeability
%
Safety Margin
Engineers use gradeability analysis during EV design and validation to size motors, select gear ratios, verify hill-start capability, and ensure compliance with performance requirements for real-world driving conditions, including steep roads and fully loaded operation.
Example:
For an EV of 1500 kg, having a Wheel Radius of 0.3 m, Peak Motor Torque of 200 Nm, Coefficient of Rolling Resistance of 0.015, Drivetrain Efficiency of 90% and Gear Ratio of 10, to climb an inclination of 18°
Force at Wheels = (200 x 10 x 90)/(0.3 x 100) = 6000 N
Rolling Resistance = 1500 x 9.81 x 0.015 x cos18° = 210 N
Gradient Resistance = 1500 x 9.81 x sin18° = 4547 N
Total Resistance = 210 + 4547 = 4757 N
Maximum Gradeability = ((6000-210)/ (1500 x 9.81)) x 100 = 39.3%
Safety Margin = Force at Wheels/Total Resistance = 1.26
Thus, the vehicle can climb an 18° inclination at a safety margin of 1.26.
