A battery management system for managing a plurality of subsystem circuits and functions of a mobile communication device powered by a battery is disclosed. The battery management system includes a battery monitoring circuit, a user interface, and a battery management module. The battery monitoring circuit is operable to monitor a present battery capacity and generate a battery capacity signal based on the present battery capacity. The user interface is operable to receive a user-input allocation of battery capacity among the subsystem circuits and functions. The battery management module is operable to receive the user-input allocation and the battery capacity signal, and to selectively disable each subsystem circuit or function when each subsystem circuit or function has depleted its allocation of battery capacity.