Similar to the range test, which is often done at the same time, the car under test is being fully charged and then driven to below 5% state of charge. Battery capacity can then be calculated with the driven kilometers and average consumption. If there is a greater difference between available battery size and rated battery size the car manufacturer decided to reserve a buffer which can not be accessed by the user. This leads to shorted range but allows for faster charging and less noticable battery degradation. Furthermore, this test can be used to determine battery degradation when the available battery capacity was tested previously.
To learn more about the procedure of the range test you can watch the video below.
Recorded Test Results
All recorded battery capacity tests of every car tested and listed here can be found on the battery capacity test results overview.