Self-checking emergency light unit and method of operating a self-checking emergency light unit

A self-checking emergency light unit (2), in particular a self-checking emergency light unit (2) of a passenger transport vehicle, such as an aircraft, a ship, a rail car or a road vehicle, includes a power input terminal (4) coupleable to an external power supply for receiving power therefrom, an illumination circuit (6) coupled to the power input terminal (4), the illumination circuit (6) having at least one light source, an emergency power source (8) coupled to the power input terminal (4) and to the illumination circuit (6), wherein the emergency power source (8) is adapted to store electrical energy received via the power input terminal (4) and to provide electrical energy to the illumination circuit (6) in an emergency operation, a discharge circuit (10) coupled to the emergency power source (8), wherein the discharge circuit (10) is adapted to effect a discharge of the emergency power source (8) in a power down operation, and an operational check module (12) coupled to the emergency power source (8), wherein the operational check module (12) is configured to sense at least one electric characteristic of the emergency power source (8) during the power down operation and to determine an operational status of the emergency power source (8) from the at least one electric characteristic during the power down operation.