Speed - the faster the bike is travelling, the less the range

Pedalling - how much/often the rider is pedalling

Weight - weight of the bike, rider, gear, and cargo

Terrain - how much the terrain varies - hills, bumps, road surface

Drag - the combined aerodynamic drag of the rider and bike plus wind/weather

Temperature - extreme temps can decrease battery usefulness

Battery - KWh output of the battery and age of the battery

Motor - efficiency of the motor drive system

Tires - tire type and tire pressure

How much you pedal