A battery-powered, modular surgical device, comprising:an electrically powered surgical instrument interfacing with bodily tissue during surgery and requiring a pre-determined minimum amount of electrical energy to power the surgical instrument completely through a surgical procedure； anda power module assembly having:at least one modular battery supplying power for the surgical instrument during use and having a current state of electrical charge； anda control circuit electrically coupled to the at least one modular battery and to the surgical instrument and comprising a memory and at least one microprocessor, the memory storing data regarding the pre-determined minimum amount of electrical energy, and the microprocessor being programmed to:monitor and determine the current state of electrical charge of the at least one modular battery；compare the current state of electrical charge of the at least one modular battery to the pre-determined minimum amount of electrical energy； andmaintain the battery in a non-discharge state if the current state of electrical charge of the battery is below the pre-determined minimum amount of electrical energy.
