Surgical instruments and batteries for surgical instruments

A surgical system comprising:

• a battery pack, wherein the battery pack comprises:
• a plurality of cells, wherein at least a portion of the plurality of cells are not electrically connected to one another;
• a casing defining an interior cavity having at least one interior cavity wall, wherein the at least one interior cavity wall comprises a first electrode electrically connected to an anode of the battery pack and a second electrode electrically connected to a cathode of the battery pack;
• and
• a battery drain positioned within the interior cavity, wherein the battery drain comprises first and second contacts electrically connected to one another, wherein the first and second contacts are in contact with the at least one interior cavity wall, and wherein the battery drain is positionable at a first position within the interior cavity where the first and second contacts are not in electrical contact with the first and second electrodes and a second position where the first contact is in electrical contact with the first electrode and the second contact is in electrical contact with the second electrode;
• an end effector;
• and
• a handle operatively coupled to the end effector, wherein the handle comprises a trigger to actuate the end effector, wherein the handle defines a cavity for receiving the battery pack, wherein the handle comprises a connector positioned to connect the plurality of cells to one another when the battery pack is inserted into the cavity, and wherein the handle defines an extension member positioned to contact the battery drain as the battery pack is inserted into the cavity to push the battery drain to the second position.