The bq2012 Gas Gauge IC is intended for battery-pack or in-system installation to maintain an accurate record of available battery charge. The IC monitors a voltage drop across a sense resistor connected in series between the negative battery terminal and ground to determine charge and discharge activity of the battery.

Self-discharge of NiMH and NiCd batteries is estimated based on an internal timer and temperature sensor. Compensations for battery temperature and rate of charge or discharge are applied to the charge, discharge, and self-discharge calculations to provide available charge information across a wide range of operating conditions. Battery capacity is automatically recalibrated, or "learned," in the course of a discharge cycle from full to empty.