Electric power control assembly for bicycle electronic device and electric power control system having the same and control method thereof

An electronic power control system, which is adapted to be disposed on a bicycle, comprising:

• a power source;
• a control module, which is electrically connected to at least one electronic device on the bicycle and is adapted to control the at least one electronic device on the bicycle to operate;
• and
• an electronic power control assembly, comprising:
• a sensing unit which is adapted to sense a motion state of the bicycle;
• a first timing unit which is adapted to count a first predetermined time period;
• and
• a first control unit, which is electrically connected to the power source, the sensing unit, and the first timing unit, wherein when the sensing unit senses that the bicycle is in a moving state, the first control unit controls the first timing unit to recount and controls the power source to supply electricity to the control module;
• when the counted first predetermined time period in the first timing unit is completed, the first control unit controls the power source to stop supplying electricity to the control module.