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Electric Bicycle Battery Degradation Calculator

This calculator estimates the remaining usable capacity of an electric bicycle battery after a chosen number of equivalent full cycles and a specified average capacity-loss rate. It also translates that loss into an estimated change in riding range, helping riders compare current performance with the battery when it was new.

Use it for maintenance planning, replacement budgeting, or evaluating whether shorter range is broadly consistent with normal battery aging. Real battery health also depends on temperature, storage state of charge, charging speed, cell chemistry, and calendar age, so the result is a planning estimate rather than a diagnostic test.

Calculator inputs

Wh
km
cycles
%
Result
—
Calculated result
Estimated capacity loss—
Remaining capacity—
Estimated range loss—
Remaining range—

1. Enter the new-battery capacity
Use the rated watt-hour capacity shown on the battery or manufacturer specification.

2. Add the original range
Enter a realistic full-charge range from when the battery was new.

3. Estimate equivalent full cycles
Two half discharges count approximately as one equivalent full cycle.

4. Set the loss rate
Use a conservative percentage loss per 100 cycles that matches your planning assumption.

5. Review capacity and range
Compare the estimated remaining watt-hours and riding range with observed performance.

Capacity loss (%) = (Equivalent full cycles ÷ 100) × Loss rate per 100 cycles Remaining capacity = Original capacity × (1 − Capacity loss ÷ 100) Remaining range = Original range × (Remaining capacity ÷ Original capacity)

The model assumes range changes in direct proportion to usable battery capacity. It does not separately model temperature, tire pressure, terrain, rider mass, or calendar aging.

What the result means

A higher percentage indicates less usable energy and a proportionally shorter estimated riding range.

Observed range can vary significantly with riding conditions even when battery capacity is unchanged.

Given: 500 Wh original capacity, 60 km original range, 400 equivalent full cycles, and 1.5% loss per 100 cycles.

Calculation: Capacity loss = (400 ÷ 100) × 1.5% = 6%. Remaining capacity = 500 × 0.94 = 470 Wh. Remaining range = 60 × 0.94 = 56.4 km.

Result: Estimated capacity loss is 6%, leaving about 470 Wh and 56.4 km of range under comparable conditions.

What is an equivalent full cycle?

It is cumulative energy use equal to one complete discharge and recharge. For example, two uses of 50% each are roughly one equivalent full cycle.

Does fast charging increase degradation?

Higher charging power can increase heat and stress in some batteries, but the effect depends on the battery management system, cell chemistry, and temperature.

Why does my actual range differ from the estimate?

Wind, hills, assistance level, rider weight, tire pressure, and temperature can change energy consumption independently of battery health.

Can capacity loss exceed 100% in the calculator?

No. The displayed loss is capped at 100% because usable capacity cannot be negative.

Is this the same as a battery health test?

No. A proper health test measures delivered energy under controlled conditions; this calculator estimates wear from cycle assumptions.