Patent ID: 7405571

Claim:
A method for measuring a capacity of a battery, the method comprising: generating virtual calibration data of the battery based on one or more characteristics of the battery; determining an internal impedance (R i ) of the battery, including applying a first load (I 1 ) across the battery, measuring a first voltage (V 1 ) across the battery while the battery is being applied with the first load (I 1 ), applying a second load (I 2 ) to the battery for a predetermined time duration in addition to the first load (I 1 ), and measuring, during the predetermined time duration, a second voltage (V 2 ) across the battery in view of the first load (I 1 ) and the second load (I 2 ), wherein the internal impedance is determined based on at least a portion of V 1 , V 2 , I 1 , and I 2 ; determining a virtual open circuit voltage (V oc ) of the battery based on the internal impedance of the battery while the battery is being used; and estimating the capacity of the battery based on the determined virtual open circuit voltage of the battery and the virtual calibration data of the battery, while the battery is being used.