Patent ID: 8271217

Claim:
An electrical device powered by a battery, comprising: voltage reading circuitry configured to monitor the voltage of a power source connector that is charging the battery; transition phase determining circuitry operatively connected to the voltage reading circuitry to determine that the battery has entered a transition phase based on sensing an abrupt change in the voltage; and battery capacity determining circuitry configured to determine, in response to the transition phase determining circuitry determining that the battery is in the transition phase, a capacity of the battery based on a transition phase battery capacity model that defines the battery's capacity as a function of the battery's voltage; the transition phase determining circuitry being further configured to determine that the transition phase has ended based on the lapse of a predetermined time period from the start of the transition phase; and the transition phase battery capacity model being determined from both a non-transition battery capacity charge model and a non-transition battery capacity discharge model, all three models defining the battery's capacity as a function of its voltage.