An apparatus for charging a battery of an electric device that has a motor by not charging the battery before the electric device is used and a method of charging a battery of an electric device that has a motor by using the apparatus. The apparatus includes a load, a motor for driving the load, a battery that provides a power supply to the motor, a generator that converts a kinetic energy that is generated by the motor to an electric energy, and a control unit that senses an amount of the load of the load and, if the amount of the load is less than a reference value, charges the battery by a first charging mode by using the electric energy output from the generator.