Estimation of Energy Efficiency in Pedal-Assist Electric Bicycles

Pedal-assist electric bicycles (e-bikes) have emerged as a practical solution for urban mobility and sustainable transportation. Despite its relevance, accurately estimating its electric performance is challenging, as it is impacted by a complex interplay of environmental conditions, user behavior, and electromechanical characteristics. We present a method for estimating the energy performance of mechanical bicycles and e-bikes, analyzing key factors: accelerations from stops, slopes, wind, and coasting. Electric performance varies from 2.3 to 6 Wh/km. A single start-up acceleration may use 1 Wh of energy, temporarily increasing performance to 44 Wh/km. This energy could otherwise propel a cyclist over 100 to 200 meters. Slopes were the most important factor, increasing the power demand by 20 to 50 W per additional 1% slope and reducing efficiency by adding 2.5 Wh/km per 1% slope. Smart use of coasting can also help mitigate the excess of energy during frequent stops at traffic lights.