On an electric bike, the battery represents 30 to 40 % of its value. It's also the part that concerns second-hand buyers most: it ages, costs a lot to replace (€400–900), and its condition can't be seen. An e-bike listing that stays silent on the battery gets negotiated down hard. A listing that documents it sells at asking price.
What the savvy buyer actually looks for
The experienced buyer doesn't ask "how many km does it hold?" (range depends on terrain, weight, assistance level). They ask two measurable things:
- The number of charge cycles, often readable in the manufacturer's diagnostic. A battery rated for roughly 500–1000 cycles before dropping below 80 % capacity: at 300 cycles, it's young; at 900, it's past the first third of its life.
- The SoH (State of Health), the remaining capacity as a percentage of original capacity. This is the key number.
How to get these figures
Depending on the motor, several options exist:
- Bosch: the dealer diagnostic (or the app depending on generation) gives cycles and health. A printout of the diagnostic attached to your listing beats any amount of talking.
- Shimano STEPS, Specialized (Mission Control), Bafang: manufacturer apps display health status or at least cycle counts.
- Without a tool: a fully documented charge (charge time, uphill behavior on a known route) gives an honest ballpark.
A motor fault code (Bosch, Shimano) should be addressed or at least mentioned: hiding it always backfires at test ride time. The technical assistant decodes these codes and flags whether they affect the battery, motor, or a sensor.
