SLUUCH2 March 2021 BQ40Z50-R2
The total battery capacity is found by comparing states of charge before and after charge and discharge with the amount of charge passed. When an applications load is applied, the impedance of each cell is measured by comparing the open circuit voltage (OCV) obtained from a predefined function for present state-of-charge with the measured voltage under load.
Measurements of OCV and charge integration determine chemical state-of-charge and chemical capacity (QMax).
The BQ40Z50-R4 acquires and updates the battery-impedance profile during normal battery usage. It uses this profile, along with state-of-charge and the QMax values, to determine FullChargeCapacity and RelativeStateOfCharge specifically for the present load and temperature. FullChargeCapacity reports a capacity or energy available from a fully charged battery reduced by Reserve Cap-mAh or Reserve Cap-cWh under the present load and present temperature until voltage reaches the Term Voltage.