Understanding E-Bike Battery and Range
Range is the spec buyers worry about most and the one manufacturers exaggerate most. The good news is that a little battery literacy makes it easy to compare bikes honestly and set realistic expectations.
Watt-hours are the number that matters
A battery's real capacity is measured in watt-hours (Wh), which is voltage multiplied by amp-hours. A 48V, 14Ah pack is 672 Wh. Wh lets you compare any two batteries directly, regardless of their voltage, whereas the advertised 'up to X miles' figure is marketing.
As a rule of thumb, more Wh means more range and, usually, more weight and cost. Typical commuter e-bikes carry 400-700 Wh; long-range and cargo bikes often exceed 1,000 Wh or offer a second battery.
Estimating real-world range
A practical estimate is Wh divided by 10-25 Wh per mile. You'll use around 10-15 Wh/mi with light pedal-assist on flat ground, and 20-25+ Wh/mi if you lean on high assist or a throttle, carry weight, climb hills, or fight headwinds.
So a 500 Wh battery might deliver 35-50 miles of gentle assisted riding, but closer to 20-25 miles of throttle-heavy hilly riding. Claimed ranges assume the best case, so treat them as a ceiling, not an average.
Making the battery last
Lithium e-bike batteries are rated for hundreds of charge cycles. To extend their life, avoid routinely draining to empty or leaving them at 100% for long periods, store them around room temperature (not in freezing or scorching conditions), and use the charger that came with the bike.
If you ride far or want flexibility, look for a removable battery (easy to charge indoors and to replace years later) or a dual-battery option that roughly doubles your range.
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