A: When the UPS shows fault code 65 (low battery voltage), please follow the troubleshooting steps below:
1.Check the actual total battery voltage. If the total voltage is out of the normal range, measure the voltage of each battery cell and replace any defective cells.
2.Check whether the series cables between batteries and the connection cables from batteries to the internal power board of the UPS are securely connected (no loose connections, obvious burning, etc.). 
If any abnormality is found, power off the unit first, replace the cables, then restart the UPS to check if the fault is cleared.
3.Check whether the parameters displayed on the UPS panel / MTR software are consistent with the actual measured values (battery voltage, battery capacity, etc.). If the actual measured values are normal but the displayed values on the UPS screen or MTR software do not match, the internal battery detection circuit of the UPS may be faulty.
Path to view battery data in MTR:Home page → Battery Data
4.If all three checks above show no abnormality, use the MTR software to verify whether the configured battery parameters match the actual battery specifications in use.
Path to check battery parameter settings in MTR:ServSetting → Battery Setting (Please carefully check and compare all items in this section.)