An electrically operated surgical instrument, comprising: a surgical end effector having an actuation assembly operable to effect a surgical procedure when actuated, a part of said actuation assembly operable to move between a start position and a fully actuated position； and a handle connected to said end effector for actuating said actuation assembly, said handle having: a self-contained power supply disposed entirely within said handle； a drive assembly disposed entirely within said handle and having: an electrically powered motor； and a controller connected to said motor and operating said motor； a transmission mechanically connecting said motor to said moving part and being operable to displace said moving part between said start and extended positions； and a manual release mechanically coupled to said transmission to selectively interrupt said transmission and, during interruption, displace said moving part towards said start position independent of operation of said motor.
