An electrical device includes a memory storing a value indicative the remaining available rated capacity of one or more batteries. The stored value is changed in use to reflect reducing capacity. The initial stored value is chosen so that there is a very high (e.g. >99.9%) confidence that the one or more batteries will provide at least the capacity indicated by the initial stored value. This reduces the chance of failure during emergency procedures. The one or more batteries may be integral to the electrical device. An override facility is provided.

Various implementations include a battery disconnect device that includes a breaker, a housing, and a bus bar. The breaker has a pivot portion and an actuation portion, and the actuation portion has an actuation face. The pivot portion has an axis of rotation about which the breaker is pivotable. The housing defines a chamber, and the chamber is in fluid communication with a gas generator via an inlet defined by an inlet wall of the housing. The breaker is disposed within the chamber in a first position in which the actuation face is adjacent the inlet and inlet wall and combustion gas from the gas generator pushes on the actuation face to cause the breaker to pivot about the axis of rotation of the pivot portion to a second position, which causes the breaker to break the bus bar.

Disclosed is a method of controlling a modular battery powered handheld surgical instrument. The surgical instrument including a battery, a user input sensor, a controller, a radio frequency (RF) drive circuit, an ultrasonic transducer, ultrasonic transducer drive circuit, and an end effector. The end effector including an electrode electrically coupled to RF drive circuit, an ultrasonic blade acoustically coupled to the ultrasonic transducer, and a sensor to measure tissue parameters. The method includes applying an RF current drive signal to the electrode by the RF drive circuit; applying an ultrasonic drive signal to the ultrasonic transducer by the ultrasonic transducer drive circuit to acoustically excite the ultrasonic blade; controlling intensity, wave shape, and/or frequency of the RF current drive signal and the ultrasonic drive signal on a sensed measure of a tissue or user parameter.

Disclosed is a surgical instrument that includes a battery assembly, a handle assembly, and a shaft assembly where the battery assembly and the shaft assembly are configured to mechanically and electrically connect to the handle assembly. The battery assembly includes a control circuit configured to generate a digital waveform. The handle assembly includes a first stage circuit configured to receive the digital waveform, convert the digital waveform into an analog waveform, and amplify the analog waveform. The shaft assembly includes a second stage circuit coupled to the first stage circuit to receive, amplify, and apply the analog waveform to a load.

Systems and methods for battery testing including a holder system. The holder system is designed to couple one or more transducers to a battery under test, wherein the one or more transducers are configured for electrochemical-acoustic signal interrogation (EASI) of the battery. The holder system includes at least one arm to house at least one transducer to be coupled to the battery, and a pressure applying device to apply pressure to the at least one transducer, and to control pressure between the at least one transducer and the battery. The holder system is also configured to determine the pressure between the at least one transducer and the battery and adjust the pressure applied to the at least one transducer based on the determined pressure.

A surgical instrument is disclosed. The surgical instrument includes a handle assembly that includes a handle housing. The handle housing comprises two asymmetric portions, a first portion configured to support mechanical and electrical components of the surgical instrument and a second portion comprising a removable cover.

Disclosed is a method of controlling a modular battery powered handheld surgical instrument. The surgical instrument including a battery, a user input sensor, a controller, a radio frequency (RF) drive circuit, an ultrasonic transducer, ultrasonic transducer drive circuit, and an end effector. The end effector including an electrode electrically coupled to RF drive circuit, an ultrasonic blade acoustically coupled to the ultrasonic transducer, and a sensor to measure tissue parameters. The method includes applying an RF current drive signal to the electrode by the RF drive circuit; applying an ultrasonic drive signal to the ultrasonic transducer by the ultrasonic transducer drive circuit to acoustically excite the ultrasonic blade; controlling intensity, wave shape, and/or frequency of the RF current drive signal and the ultrasonic drive signal on a sensed measure of a tissue or user parameter.

Provided is a system including a surgical instrument comprising a handle assembly comprising a handle; a shaft assembly coupled to the handle assembly; and a flexible circuit. The handle assembly comprises a proximal portion of the flexible circuit and the shaft assembly comprises a distal portion of the flexible circuit; the shaft assembly further comprising: an exterior shaft positioned around the distal portion of the flexible circuit and configured to change position while a sub-portion of the distal portion of the flexible circuit remains stationary; and shaft control electronics comprising a stationary portion and a non-stationary portion, the stationary portion coupled to the distal portion of the flexible circuit and the non-stationary portion coupled to the exterior shaft; wherein the stationary portion of the shaft control electronics is configured to measure a distance to the non-stationary portion of the shaft control electronics as the exterior shaft changes position.

A surgical instrument comprises a shaft assembly comprising a shaft and an end effector coupled to a distal end of the shaft; a handle assembly coupled to a proximal end of the shaft; a battery assembly coupled to the handle assembly; a driver configured to drive movement of at least one component of the surgical instrument; a motor powered by the battery assembly and configured to actuate the driver using an output of the motor; and a controller for the motor, configured to perform a limiting operation to the output of the motor when a limiting condition is met, wherein the limiting condition is determined based at least in part on a tissue characteristic.

Systems and methods for battery testing including a holder system. The holder system is designed to couple one or more transducers to a battery under test, wherein the one or more transducers are configured for electrochemical-acoustic signal interrogation (EASI) of the battery. The holder system includes at least one arm to house at least one transducer to be coupled to the battery, and a pressure applying device to apply pressure to the at least one transducer, and to control pressure between the at least one transducer and the battery. The holder system is also configured to determine the pressure between the at least one transducer and the battery and adjust the pressure applied to the at least one transducer based on the determined pressure.