Hub Motor Simulator & Range Estimator
Simulate EV performance for DIY e-bikes and scooters. Calculate theoretical vs. real-world speed, estimated range, and torque based on battery voltage, KV rating, and load.
Motor & Battery Config
About
Building a DIY electric vehicle involves balancing voltage, motor winding speed (KV), and physical wheel geometry. A common pitfall is calculating speed based purely on unloaded RPM, which results in disappointment on the road. This simulator bridges the gap between theoretical physics and real-world application. It applies aerodynamic drag coefficients and rolling resistance factors to provide a realistic estimate of loaded speed.
Range anxiety is a critical concern for EV builders. By integrating battery capacity (Wh) with consumption estimates (Wh/km), this tool helps predict how far a build can travel on a single charge. Whether designing a high-torque electric scooter or a high-speed e-bike, accurate simulation prevents component mismatch and ensures the final build meets performance expectations.
Formulas
The theoretical unloaded speed vmax is calculated from the motor constant and applied voltage:
(Constant converts inches/min to mph)
To estimate real-world range R, we calculate total energy E and divide by average consumption Cavg:
Reference Data
| Parameter | Formula / Value | Description |
|---|---|---|
| Angular Velocity (ω) | KV × V | Rotations Per Minute (RPM) |
| Tangential Speed (v) | ω × C | Linear speed based on circumference |
| Wheel Circumference (C) | π × d | Distance per rotation |
| Efficiency Factor (η) | 80-85% | Heat/Friction losses (Brushless DC) |
| Battery Capacity (E) | Ah × V | Total Energy in Watt-hours |
| Voltage Sag | ≈ 2-4 V | Drop under high load |