A surgical system comprising a generator and a surgical instrument configured to receive power from the generator is disclosed. The surgical instrument comprises a housing, a shaft defining a longitudinal axis, an end effector, and an internal charge accumulator. The housing comprises a motor. The end effector is operably responsive to actuations from the electric motor, transitionable between an open and closed configuration, and rotatable about an articulation axis transverse to the longitudinal axis. The generator is incapable of supplying a sufficient power directly to the motor to perform the actuations. The internal charge accumulator is in electric communication with the generator and supplies power to the motor. The internal charge accumulator is chargeable by the generator to a threshold value at a charge rate dependent on a charge level of the internal charge accumulator. The charge rate is independent of a charge expenditure by the surgical instrument.