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Why doesn't my Battery Management System (AP9921X) record Ohmic Values?


Issue

My Battery Management System (AP9921X) is not recording Ohmic Values.


Product Line

Battery Management
AP9921X only
 

Environment

All firmware versions
All serial numbers


Cause

Ohmic Values may not be recording for a number of possible, by design reasons. Please review the items listed below to try and correct the issue.


Resolution


Here are some guidelines that need to be met in order for the APC by Schneider Electric Battery Management System (AP9921X) to record Ohmic Values:
  • A selected set of voltage values obtained during discharge operation shall be used to derive the ohmic value of each individual battery. The time delay before gathering this data shall be programmable for times between 10 seconds and 300 seconds.
  • The ohmic value calculation shall not be performed unless the batteries were fully charged prior to the discharge event.
  • The individual battery ohmic values shall be saved in non-volatile memory and displayed graphically.
  • The most recent set of ohmic values shall be indicated in the “Ohmic Values” page, along with date/time, discharge current and the pilot temperature associated with that event. 
  • Any Ohmic calculation which results in a value expressed in a  Negative Number will be displayed as a 0 (Zero). This will indicate that the individual circuit needs to be calibrated to provide an accurate Ohmic Value.
  • If the discharge current was at least 20% of the battery capacity when the selected set of voltages were obtained, the ohmic values shall be calculated.
  • If you are not seeing any of these values being recorded or have any questions, please obtain the event.txt, data.txt and config.ini from the network management card inside of the Battery Management System and contact APC by Schneider Electric support. Please review APC knowledge base article FA156131 for instructions on how to obtain the requested files.



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