Electrically power assisted bicycle

An electrically power assisted bicycle comprising:

• an electric motor that generates an assist force to assist human power of a rider;
• a detachable battery that supplies electric power to at least the electric motor;
• and
• an operation panel including an operation button that accepts an input operation from the rider, a time display area that displays time, a controller configured or programmed to control a display in the time display area, and a built-in battery that supplies electric power to the controller;
• wherein
• the controller is supplied with the electric power from the detachable battery when the detachable battery is attached to the electrically power assisted bicycle and the electrically power assisted bicycle is in a power-on state;
• and
• the controller is configured or programmed to display, in the time display area, information indicating that a remaining capacity of the built-in battery is insufficient when the electrically power assisted bicycle is turned on from a power-off state in a state in which the remaining capacity of the built-in battery is insufficient.