A reusable battery indicator system for indicating a characteristic of a battery , the reusable battery indicator system comprising: a battery comprising a first battery terminal, a second battery terminal and a label; and a battery indicator , the battery indicator comprising; a voltage sensor configured to convert sensed analog characteristics of the battery to digital information; a communication circuit communicatively connected to the voltage sensor ; an antenna operatively coupled to the communication circuit ; and a connection mechanism having a connector and a retainer , the connector being electrically connected to the voltage sensor , the connector being adapted to be removably and electrically connected to the first battery terminal, thereby providing an electrical connection between the voltage sensor and the first battery terminal when the connector is connected to the first battery terminal, and the retainer being adapted to be removably and electrically connected to a can of the battery , thereby providing an electrical connection between the voltage sensor and the can of the battery ; wherein the connection mechanism includes an electrical key , and the electrical key comprises one of a split matching antenna network, an optical sensor, or a capacitive coupling connection, and the battery label comprises an electrical lock, and the electrical key interacts with the electrical lock to allow the indicator to function. a battery comprising a first battery terminal, a second battery terminal and a label; and a battery indicator , the battery indicator comprising; a voltage sensor configured to convert sensed analog characteristics of the battery to digital information; a communication circuit communicatively connected to the voltage sensor ; an antenna operatively coupled to the communication circuit ; and a connection mechanism having a connector and a retainer , the connector being electrically connected to the voltage sensor , the connector being adapted to be removably and electrically connected to the first battery terminal, thereby providing an electrical connection between the voltage sensor and the first battery terminal when the connector is connected to the first battery terminal, and the retainer being adapted to be removably and electrically connected to a can of the battery , thereby providing an electrical connection between the voltage sensor and the can of the battery ; wherein the connection mechanism includes an electrical key , and the electrical key comprises one of a split matching antenna network, an optical sensor, or a capacitive coupling connection, and the battery label comprises an electrical lock, and the electrical key interacts with the electrical lock to allow the indicator to function. a voltage sensor configured to convert sensed analog characteristics of the battery to digital information; a communication circuit communicatively connected to the voltage sensor ; an antenna operatively coupled to the communication circuit ; and a connection mechanism having a connector and a retainer , the connector being electrically connected to the voltage sensor , the connector being adapted to be removably and electrically connected to the first battery terminal, thereby providing an electrical connection between the voltage sensor and the first battery terminal when the connector is connected to the first battery terminal, and the retainer being adapted to be removably and electrically connected to a can of the battery , thereby providing an electrical connection between the voltage sensor and the can of the battery ; <EOS>