Batteries & Charging
State of health (SoH)
What is State of health (SoH)?
How much of its original capacity a battery has kept, usually given as a percentage of what it held when new.
State of health (SoH) describes how far a battery has aged. A new pack is at 100%. As it goes through charge cycles and years of use, it holds less energy, so even a fully charged older battery takes you less far.
A worked example
Say a dealer’s test finds that a 500 Wh battery now holds 400 Wh. Its capacity is 400 ÷ 500 × 100 = 80% of new. (That’s an example calculation, not a Riding Nexus test.) Bosch says its dealers can measure the remaining capacity of a Bosch battery with a CapacityTester. Ask how the test was done when you read the result.
Common confusion
State of health is not the percentage on your display. That’s the state of charge, which tells you how full the battery is today. A short ride on a cold morning doesn’t mean the battery has aged either, because cold cuts range until the pack warms up. Our e-bike range guide explains the other things that change range, and the winter battery storage guide covers how to store a pack so it ages slowly.
Related terms
- State of charge How full a battery is right now, shown as a percentage or as bars on the display. It is an estimate made by the battery's electronics.
- Lithium-ion battery A rechargeable battery that stores energy by moving lithium ions between two electrodes. Almost every e-bike battery is a pack of lithium-ion cells.
- Battery management system The electronics inside a battery pack that watch its cells and cut charging or power when temperature, current or charge level go outside safe limits.