The bqJUNIOR™ series are highly accurate stand-alone single-cell Li-Ion and Li-Pol battery capacity monitoring and reporting devices targeted at space-limited, portable applications. The IC monitors a voltage drop across a small current sense resistor connected in series with the battery to determine charge and discharge activity of the battery. Compensations for battery temperature, self-discharge, and discharge rate are applied to the capacity measurments to provide available time-to-empty 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. Internal registers include current, capacity, time-to-empty, state-of-charge, cell temperature and voltage, status, and more. The bqJUNIOR can operate directly from single-cell Li-Ion and Li-Pol batteries and communicates to the system over a HDQ one-wire or I2C serial interface.