NOVELTY - A fuel cell system (2) for use with electrical power source comprises fuel cell body (4), fuel supply unit (5), and manual driving unit (6) operable to permit fuel transfer to body when power of power source is insufficient to drive supply unit for transferring fuel to body. The system further has switching unit. The driving unit has pump (61)/operating module (62), where pump is coupled to and in fluid communication with supply unit and is disposed with body when switching unit is operated to select indirect fuel transfer. The pump has fuel cylinder (611)/fuel delivering component (612).    USE - As a fuel cell system adapted for use with at least one electrical power source (claimed) such as direct methanol fuel cell system; as battery system; and in electronic devices such as portable electronic devices e.g. notebook computer and cell phones.    ADVANTAGE - The fuel cell system used in electronic devices, can effectively operate even when electrical power in the electronic devices is not sufficient for driving fuel cell system.    DETAILED DESCRIPTION - A fuel cell system (2) adapted for use with at least one electrical power source, comprises a fuel cell body (4) for receiving a fuel, and for generating electrical power; a fuel supply unit (5) adapted to be coupled electrically to the electrical power source, coupled to and in fluid communication with the fuel cell body, and having the fuel stored in it; and a manual driving unit (6) coupled to the fuel supply unit, and operable to permit transfer of the fuel stored in the fuel supply unit to the fuel cell body when electrical power of the electrical power source is insufficient to drive the fuel supply unit for transferring the fuel to the fuel cell body. The system further comprises a switching unit coupled to the fuel cell body, the fuel supply unit and the manual driving unit, and operable to select whether transfer of the fuel in the fuel supply unit to the fuel cell body should involve the manual driving unit. The manual driving unit includes a manual pump (61) and a manual operating module (62), where the manual pump is coupled to and in fluid communication with the fuel supply unit, and is disposed in fluid communication with the fuel cell body when the switching unit is operated to select indirect transfer of the fuel, where the manual operating module is coupled to the manual pump for driving operation of the manual pump so as to draw the fuel from the fuel supply unit. The manual pump includes a fuel cylinder (611) and a fuel delivering component (612), where the fuel cylinder is disposed in fluid communication with the fuel supply unit and is disposed in fluid communication with the fuel cell body when the switching unit is operated to select indirect transfer of the fuel, where the fuel delivering component is partially disposed in the fuel cylinder for transferring the fuel to the fuel cell body.    DESCRIPTION OF DRAWING(S) - The figure shows schematic block diagram of electronic device incorporating fuel cell system.    Fuel cell system (2)    Electronic device (3)    Fuel cell body (4)    Fuel supply unit (5)    Manual driving unit (6)    Electrical power source (31)    Power management system (32)    System electrical load (33)    Fuel container (51)    Fuel supply pump (52)    Manual pump (61)    Manual operating module (62)    Lithium battery unit (311)    Alternating current/direct current (AC/DC) converting unit (312)    Fuel cylinder (611)    Fuel delivering component (612)