Charging system for mobile device with multiple batteries

A charging system for a mobile device including a charging connector, a first charging component, a second charging component, a flexible printed circuit board, a first battery, and a second battery is provided. The first charging component includes a first input terminal electrically connected to the charging connector and a first output terminal. The second charging component includes a second input terminal electrically connected to the first output terminal and a second output terminal. The flexible printed circuit board includes a first charging connecting terminal and a second charging connecting terminal. The first charging connecting terminal is electrically connected to the second output terminal, and the second charging connecting terminal is electrically connected to a ground terminal. The flexible printed circuit board electrically connects the first battery and the second battery in series between the first charging connecting terminal and the second charging connecting terminal.