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BMS AP9921X-AP9922; Charger Alarms

Issue:

Product line:

Battery Management System (BMS) AP9921X & AP9922

Environment:

All models, all serial numbers

Cause:

Critical Alarms

High String Voltage:

1). the voltage of a battery string is above the configured threshold. Default high threshold: 2.4 V per cell for lead-acid batteries (or 14.4vdc per jar) See Cell Max Voltage Limit for configuration information.

2).The string charger may be defective or improperly adjusted. If uncorrected, this condition can cause permanent damage to the batteries. Adjust the DC string- charging voltage to the voltage specified by the battery manufacturer.

Low String Voltage:

1). the voltage of a battery string is below the configured threshold. Default low threshold: 2.15 V per cell for lead-acid batteries (or 12.9vdc per jar) Check for open fuses or connections in the Battery Management System wiring. (An open fuse or connection activates the Management Controller LED.) See Cell Min Voltage Limit for configuration information.

2). If the Management Controller LED is not active, and all battery voltages are present and balanced, the string charger may be defective or improperly adjusted. If uncorrected, this condition can cause permanent damage to the batteries. Adjust the DC string- charging voltage to the voltage specified by the battery manufacturer.

System on Battery:

The charger is not receiving power. The batteries are providing power to the load. Note: Any negative current flow of over 10 A and 2 seconds cause the Discharge Alarm. However, to initiate a Discharge Test, the Battery Management System requires a sustained 10-A discharge for more than 5 seconds. Investigate the loss of power to the charger and restore it as soon as possible.

High Ripple Current:

The detected ripple current exceeds the alarm threshold. Default high ripple current: 5%. Investigate the source of high AC current in the charger output. A high ripple current may indicate electronic issues with the rectifier, or harmonic and other distortions caused by loads on the inverter of the UPS. To prevent premature battery failure, immediately correct any ripple current greater than 5% of battery ampacity.

Resolution:

Correct symptom or alarm