A surgical instrument assembly, comprising: a handle, comprising: a battery cavity; and electrical contacts; a battery removably positionable in said battery cavity, wherein said battery is configured to engage said electrical contacts when said battery is in an operably seated position in said battery cavity; diagnostic means for assessing whether said handle is suitable for operation; characterised by: a battery lockout configured to: permit said battery to be operably seated in said battery cavity when said diagnostic means determines that said handle is suitable for operation; and prevent said battery from being operably seated in said battery cavity if said diagnostic means determines that said handle is not suitable for operation, wherein said battery lockout comprises a lock arm movable between an unextended position and an extended position, and wherein said lock arm is configured to prevent said battery from being operably seated in said battery cavity when said lock arm is in said extended position, wherein said lock arm comprises a cantilever beam integrally formed with said handle. a handle, comprising: a battery cavity; and electrical contacts; a battery cavity; and electrical contacts; a battery removably positionable in said battery cavity, wherein said battery is configured to engage said electrical contacts when said battery is in an operably seated position in said battery cavity; diagnostic means for assessing whether said handle is suitable for operation; characterised by: a battery lockout configured to: permit said battery to be operably seated in said battery cavity when said diagnostic means determines that said handle is suitable for operation; and prevent said battery from being operably seated in said battery cavity if said diagnostic means determines that said handle is not suitable for operation, wherein said battery lockout comprises a lock arm movable between an unextended position and an extended position, and wherein said lock arm is configured to prevent said battery from being operably seated in said battery cavity when said lock arm is in said extended position, wherein said lock arm comprises a cantilever beam integrally formed with said handle. a battery lockout configured to: permit said battery to be operably seated in said battery cavity when said diagnostic means determines that said handle is suitable for operation; and prevent said battery from being operably seated in said battery cavity if said diagnostic means determines that said handle is not suitable for operation, permit said battery to be operably seated in said battery cavity when said diagnostic means determines that said handle is suitable for operation; and prevent said battery from being operably seated in said battery cavity if said diagnostic means determines that said handle is not suitable for operation, wherein said battery lockout comprises a lock arm movable between an unextended position and an extended position, and wherein said lock arm is configured to prevent said battery from being operably seated in said battery cavity when said lock arm is in said extended position, wherein said lock arm comprises a cantilever beam integrally formed with said handle.