A battery charger supporting 3C (computer, communication, consumer electronics) products such as a mobile telephone, a PDA, a notebook computer, a digital camera, a digital video camera, etc. The battery charger is constructed to include a body, a circuit board, a reel assembly, an outlet lead wire, a rotable reel, a securing axle, a slide switch, and a two-pinned plug. Apart from a terminal at one end of the retractable outlet lead wire being adapted to enable connecting to a jack of a mobile phone and thereby charge the mobile phone, the battery charger is also configured with a battery recess that supports inserting of a mobile phone battery therein, whereby charging of the mobile phone battery can be accomplished.