Performance
From a biological and mechanical viewpoint, using a bicycle is extraordinarily efficient. It’s simply the most efficient human-powered means of transportation in terms of energy a person must expend to travel a given distance. From a mechanical viewpoint, 85-90% of the energy delivered by the rider into the pedals is transmitted to the wheels through the gearings.
A person biking at low to medium speeds of around 10–15 mph (16–24 km/h) uses only the energy required to walk. Air drag, which is proportional to the square of speed, requires dramatically higher power outputs as speeds increase. If the rider is sitting upright, the rider’s body creates about 75% of the total drag of the bicycle/rider combination.
There are many erroneous claims in electrical bike brochures that grossly overstate their autonomy or range.
The range of the battery depends on:
a) The power delivered by the motor, if it’s a very weak motor running with low amps, the battery pack could run for a longer time. It’s similar when the cyclist inputs a big share of the power by pedaling hard, or..
b) When riding at a very low speed, as mentioned , air drag is cube to speed.
c) energy capacity of the battery pack Wh
d) overall efficiency of the electric system and mechanical system of the bike.