US Patent 8665214 Extending battery life of a portable electronic device

A particular method includes determining a battery charge value of a battery at a particular time and comparing the battery charge value at the particular time to a threshold battery charge value of a battery usage profile associated with the particular time, where the threshold battery charge value varies over time (e.g., a dynamic threshold). When the battery charge value does not satisfy the threshold battery charge value, the method includes prompting a user to select a power save mode. For example, the power save mode may include activating a different backlight element of a plurality of backlight elements of a display device in response to a motion sensor of a portable electronic device detecting movement of the portable electronic device from a first orientation to a second orientation.