NOVELTY - The method involves calculating increase in a charge stored in a battery (100) during two respective charge phase of the battery. A reduction of the charge stored in the battery is calculated by multiplying predetermined discharge current corresponding to an operational mode of an electrical device (1700) in an amount of time. A stored charge in the battery is calculated based on a prior determined stored charge in the battery and one of the calculated reductions in the charge. A state of charge (1714) of the battery is calculated based on the calculated stored charge.    USE - Method for estimating a state of charge for a rechargeable battery i.e. lithium-based battery such as lithium ion battery and lithium polymer battery, of a battery-powered electrical device (claimed). Uses include but are not limited to a mobile computer such as Palm device, personal digital assistant, laptop and notebook computer, mobile email device such as a research in motion Blackberry(RTM: smart phone device), mobile phone such as cell phone, handheld media player such as handheld music and video player Apple iPod(RTM: Portable media player) device, handheld game console, wireless headset such as Bluetooth headset, personal navigation device such as handheld global position system device, and handheld digital video camera.    ADVANTAGE - The method accurately determines the amount of charge stored in a battery in an inexpensive manner. The method efficiently estimates a charge stored in a battery by multiplying estimated charge currents supplied during charge phases and estimated discharge currents discharged during operational modes.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a method for tracking a state of charge of a recharge-able battery of an electronic device    (2) a battery-powered electrical device comprising a battery manager.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of an electrical device that incorporates a battery manager.    Battery (100)    Battery manager (402)    Electrical device (1700)    Indicator (1710)    State of charge (1714)