A secondary power source system for a communication device includes a charging unit configured to receive a primary power input and restrict a current used for charging to a predetermined amount. The current is part of a first output of the charging unit. The system further includes a storage unit including a device that stores electrical energy, the storage unit configured to receive the first output from the charging unit with restricted current and generate a second output, a regulating unit configured to receive the second output from the storage unit and generate a third output, a selector unit configured to perform a logical OR operation with the primary power input, the first output from the charging unit and third output from the regulating unit, and to generate a fourth output, and a shutdown unit configured to shutdown operation of the secondary power system when the storage unit has been expended.