Managing Battery Power Utilization in a Mobile Computing device

A mobile computing device has a processor and storage, connected to the processor and storing computer program instructions for an operating system for the computing device. The mobile computing device also may include a display and a communications radio. An electrical connection is provided for connection to a removable battery that provides power to the components of the mobile computing device. The mobile computing device also includes an auxiliary power source configured to provide power to the components of the mobile computing device when the removable battery is not supplying sufficient power. In response to the auxiliary power source being used, the operating system performs a set of actions that prioritize processes executed by the processor, manage power utilization by those processors, communicate information to the user about available power and, in some instances, gracefully degrade operation of the processes.