How it works
range = battery capacity (Wh) ÷ average consumption (Wh per mile or km)
An e-bike battery stores energy measured in watt-hours (Wh). If you do not know your Wh figure, multiply the battery’s voltage by its amp-hours: a 36 V, 14 Ah pack is 36 × 14 = 504 Wh. Range is simply that stored energy divided by how fast you spend it. Energy use is dominated by the assist mode: pedalling along in a low-power Eco mode might draw around 7 Wh per mile, a balanced Trail/Normal mode about 12 Wh per mile, and full Turbo assist roughly 20 Wh per mile on mixed terrain — figures in line with Bosch and Shimano STEPS range data for mid-drive pedelecs. So a 500 Wh battery covers roughly 70 miles in Eco but only about 25 in Turbo. These are honest averages, not guarantees: climbing, headwind, a heavy load, cold weather, knobbly tyres and frequent stops all push consumption up and range down. Use the estimate to plan, then learn your own bike’s real numbers over a few rides.
Sources
- Range = capacity ÷ consumption Battery range (distance) = usable capacity in watt-hours ÷ average energy consumption per unit distance. Capacity (Wh) = voltage (V) × amp-hours (Ah).
- Bosch eBike range assumptions Bosch eBike Systems — range depends heavily on riding mode, terrain, rider weight and conditions; assist modes trade power for range. Eco ≈ lowest Wh/mi, Turbo ≈ highest.
- Shimano STEPS range guidance Shimano STEPS — published range varies several-fold between economy and boost modes for the same battery; consumption rises with gradient, wind and load.
FAQ
How accurate is this e-bike range estimate?
It is a planning ballpark, not a guarantee. The formula assumes a steady average consumption, but real range depends on terrain, your weight, wind, temperature, tyre pressure, tyre type and how often you stop and start. Expect your true range to vary by 30% or more around the estimate.
How do I find my battery capacity in watt-hours?
It is often printed on the battery. If you only see voltage and amp-hours, multiply them: watt-hours = volts × amp-hours. A 48 V, 10.4 Ah battery is about 500 Wh.
Which assist level should I choose?
Eco assumes light assistance (about 7 Wh per mile) and gives the longest range; Trail/Normal is a balanced everyday mode (about 12 Wh per mile); Turbo is full power (about 20 Wh per mile) for the shortest range. Pick the one closest to how you actually ride.
What drains an e-bike battery the fastest?
Climbing and high assist levels are the biggest drains, followed by headwind, heavy loads, low tyre pressure, cold temperatures and lots of stop-start riding. Smooth, flat, warm conditions in a lower assist mode maximise range.
Does cold weather reduce e-bike range?
Yes. Lithium batteries deliver less usable energy in the cold, so winter range can drop noticeably. Storing the battery indoors and only fitting it before you ride helps preserve capacity.
Can I extend my range on a ride?
Drop to a lower assist mode, keep tyres at the recommended pressure, pedal smoothly, avoid unnecessary stops, and carry a charger or spare battery for long days. Lighter loads and tucking out of the wind help too.
Range figures are estimates based on typical per-mile consumption, not your specific bike. Actual range depends on terrain, rider and cargo weight, wind, temperature, tyre choice, battery age and riding style, and can differ substantially. Use as a planning guide only.