Patent ID: 8636736

Claim:
A surgical cutting and fastening instrument comprising: a linear-cutting end effector; a shaft connected to the end effector, the shaft comprising a drive train for powering the end effector; a handle connected to the shaft; an electric, DC motor connected to the drive train for powering the drive train; and a power pack that is insertable in and removable from the handle, wherein the power pack comprises: a chargeable DC power source connected to the motor for supplying electrical power to the motor; a primary power source for charging the chargeable DC power source, wherein the primary power source is removable from the power pack when the power pack is inserted in the handle prior to operation of the instrument such that the primary power source does not supply electrical power to the motor during operation of the instrument; and a charge management circuit connected between the primary power source and the chargeable DC power source, wherein the charge management circuit: determines when the chargeable DC power source is sufficiently charged by the primary power source to operate the instrument; and comprises means for displaying a charge status of the chargeable DC power source.