BMS AP9921X-AP9922; alarms “Battery Low Capacity”
Battery Management System (BMS) AP9921X & AP9922
All models, all serial numbers
The voltage of individual batteries listed in the alarm text dropped below the configured threshold during the last discharge. Default minimum threshold is 15%. NOTE: Recorded voltage below the minimum threshold indicates that the battery will not provide adequate system backup, in relation to other batteries in the same string. You can also adjust the threshold in the Web GUI, under System>Configuration>Alarms tab. Can bump this up to 20% to clear any false positives you may get.
Identify the listed batteries immediately so that system backup time is not reduced. Check for exterior causes of this alarm, such as a loose connection or corrosion on a battery post. If the battery has no external problems, perform a follow-up reading with a battery tester. If a specific battery causes repeated alarms, the battery is failing. Replace the battery.