At this bicycle shop, your e-bike battery is tested with a Batterytester.
This is a diagnostic device that loads a fully charged battery and measures:
the available capacity
the internal resistance
This is one of the most reliable ways to assess the technical condition of a battery.
The capacity of a battery indicates how much energy it can store.
The higher the capacity, the greater the range (the number of kilometres you can ride on a single charge).
As a battery gets older, its capacity will gradually decrease. This is a normal ageing process.
The internal resistance indicates how well the battery can handle a load (for example, riding in the highest assistance level or climbing a steep hill).
Low internal resistance means the battery can deliver the requested power without much effort.
Higher internal resistance means the battery has a harder time, heats up more and is less comfortable under heavy load.
As a battery ages, its internal resistance increases. This reduces performance and, at significantly elevated levels, can be a sign of a less desirable / potentially unsafe situation.
Every battery ages:
capacity goes down
internal resistance goes up
This process (degeneration) is irreversible and depends on several factors, such as:
battery quality
usage (how often and how deeply it is discharged/charged)
age
load (heavy assistance, hills, total weight)
temperatures (heat, frost, storage conditions)
From the measured capacity loss we can conclude that the range has decreased proportionally.
The other way around, we cannot precisely predict your remaining range, because it also depends on factors like rider weight, wind, tyre pressure, assistance level and terrain.
We generally consider a battery to be worn out when:
the capacity is less than 60% of its original value, or
the internal resistance is higher than 0.30 Ω
In such cases, we strongly advise against continuing to use the battery for safety reasons.
Our recommendation is to replace the battery and/or hand it in at an official collection point.
The battery test is a snapshot in time and mainly provides insight into capacity and electrical loadability (internal resistance).
The test does not provide a complete picture of:
the remaining overall lifetime of the battery
all possible safety risks
the condition of other electronics (such as the BMS, bike controller or charger)
The load applied during the test is comparable to a challenging bike ride, where the battery is discharged in a relatively short period of time.
In very rare cases, this may cause a battery to fail. This almost exclusively happens with batteries that are already unstable, where the risk of malfunction was already high.
