A method for powering an electrosurgical instrument includes the steps of inserting a removable battery assembly into an electrosurgical instrument and activating the power control circuit to power the electrosurgical instrument. The removable battery assembly includes a power control circuit powered by at least one energy storage cell, a radio-frequency-signal-generation assembly communicatively coupled to the power control circuit and operable to selectively produce a radio-frequency signal, and a battery assembly/instrument interface operably coupled to the radio-frequency-signal-generation assembly. The battery assembly/instrument interface includes a first plurality of connectors removably connectable with at least one corresponding connector coupled to the electrosurgical instrument, at least one of the first plurality of connectors being operable to supply the radio-frequency signal to the electrosurgical instrument.