1FEATURES

• Designed for Use with 12-V Lead-Acid

Batteries in Consumer UPS Systems

• Programmable Cell Models for Enhanced

Pb-Acid Gas Gauging Performance

• Provides 10-LED Bar Graph of Run-Time

Remaining During Discharge and % Capacity

During Charge

• Can Be Easily Integrated Into Battery Cover

• Works with Pb-Acid Batteries Up to 327 Ah

• Records Cumulative Usage Data Internally for

Warranty Return Analysis

• On-Chip Temperature Sensor

• Data Interface for Retrieving Warranty

Information

• Fully Programmable Features and Thresholds

via UART Serial Interface

• State-of-Health (SoH) Determination and

Status Reporting

• Includes Configurable Signal for Audible

Low-Capacity, Low-Voltage, and Overvoltage

Warnings

• Addressable Commands for Use in

Multi-Battery Systems

• Optional Infra-Red Communications Interface

APPLICATIONS

• Stand-Alone Uninterruptible Power Supplies

• 12-V Pb-Acid Battery Monitors

• Battery Warranty Data Logging Equipment

DESCRIPTION

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