9 Tests methods 9.1 20 hour capacity check Ce 9.1.1 Throughout the duration of the tests, the battery shall be placed in a water bath at a temperature of 25 °C ± 2 °C. The terminal base of the battery shall be at least 15 mm but no more than 25 mm above the level of the water. If several batteries are in the same water bath then the distance between them and also the distance to the walls of the bath shall be at least 25 mm. 9.1.2 The battery shall be discharged with the current In (calculated according to 7.1.2) kept constant at ±2 % of the nominal value until the terminal voltage falls to 10,50 V ± 0,05 V. The duration t (h) of the discharge shall be recorded. The beginning of the discharge shall take place between 1 h to 5 h after the completion of charging according to 8.2. The battery temperature, measured in one of the middle cells, if applicable, shall be 25 ºC ±2 ºC before the discharge begins. 9.1.3 The capacity Ce is as follows: