Pb-acid battery State-of-charge Indicator with Run-Time Display

The bq78412 Pb-Acid Battery State-of-Charge (SoC) Indicator with Run-Time Display is a complete stand-alone battery gas-gauge solution designed for single 12V Pb-Acid batteries. The bq78412 displays remaining Run-Time-To-Empty during discharge and Percent (%) capacity during charge using a 10-LED (light-emitting diode) bar graph.

The bq78412 monitors battery voltage, current, and ambient temperature to calculate state-of-charge and determine remaining runtime-to-empty. Measured values can be recorded and tracked for later retrieval for warranty purposes.

Programmable cell models allow the bq78412 to be customized to a variety of Pb-Acid formulations and capacities.

Current measurements and Coulomb-counting for gas-gauging are also automatically performed by the bq78412. Current measurements use a small value sense resistor placed in the negative power path and calibrated in-circuit. This allows the precise, continuous, real-time calculation of battery capacity and run-time-to-empty values.

Temperature sensing augments gas-gauge and capacity information using a firmware algorithm to compensate for the temperature effects on capacity.

A serial port is available for configuring various programmable parameters including cell models, calibration values, serial number and date of manufacture. The serial port can operate an infra-red (IR) interface to allow connector-less data acquisition. The bq78412 is easily configurable, is fully programmed and requires no algorithm or firmware development