1. AC Input Fault
Common phenomena: The monitoring system prompts an "AC Power Loss" alarm, or some/all charging modules stop working.
Executable self-check steps:
- ● Check whether the front-end mains power (or backup power supply) is normal.
- ● Check if the incoming switch of the upper-level AC distribution box has tripped and if the fuse is blown.
- ● Check whether internal AC input circuit breakers, surge protectors and other components are in normal condition.
- ● Use a multimeter to measure the voltage at the AC input terminals of the DC panel and confirm whether it is within the rated range (e.g. 380V or 220V, with a typical allowable deviation of ±15%).
2. Charging Module (Rectifier Module) Fault
Common Phenomena: The monitoring system prompts "Module Fault" or "Module Communication Interruption".
Executable self-check steps:
- ● Check whether the AC input, DC output plugs and communication signal cables of the faulty module are securely connected, without looseness or detachment.
- ● Try to power off and remove the faulty module (hot-swappable; please pay attention to safety during operation), and observe whether the system alarm disappears and whether other modules resume normal operation.
- ● Check whether the module cooling fan operates normally, whether the ventilation ducts are blocked, and whether the casing is overheated.
3. Battery Pack Fault
Common Phenomena: The monitoring system alarms "Battery Overvoltage / Undervoltage", "Excessive Battery Voltage Difference", "Abnormal Temperature", or shows an obvious drop in output voltage when the system is under load.
Executable self-check steps:
- ● Use a multimeter to measure the total output voltage of the battery pack and determine whether it is within the normal range.
- ● Check the displayed voltage of each battery cell via the monitoring unit, and conduct on-site measurement and comparison with a multimeter to identify cells with significantly high or low voltage.
- ● Check whether the fuses or circuit breakers in the battery circuit are intact to ensure a normal connection path.
- ● Check whether the connecting copper bars (or cables) between batteries are fastened, and whether there is corrosion, looseness or abnormal heating points.
- ● Observe the charging or discharging current of the battery displayed on the monitor; under normal conditions, it shall not exceed 0.1 times the rated capacity (Ah) of the battery (i.e., 10-hour rate current).
4. DC Output and Insulation Monitoring Fault
Common Phenomena: The monitoring system alarms "Bus Voltage Abnormality", "Positive/Negative Insulation Degradation" or "XX Branch Grounding".
Executable self-check steps:
- ● If a specific grounding branch is indicated, first try to turn off the output switch of that branch and observe whether the insulation alarm resets.
- ● If no specific branch is indicated, on the premise that the connected loads permit, the "sectional troubleshooting method" may be adopted: temporarily turn off the switches of each output branch one by one in stages. If the insulation alarm disappears after turning off a certain switch, the fault can generally be determined to be in that branch. Focus on inspecting the output cables, terminals and connected load equipment of this branch.
- ● Note: This operation involves power outage. The impact on loads must be evaluated and proper safety protection must be provided.
5. Abnormality of the Monitoring Unit (Main Monitor)
Common Phenomena: No display (black screen), distorted screen on the monitoring unit, communication interruption with lower-level devices, or frequent false alarms.
Executable self-check steps:
- ● Check whether the power supply of the monitoring unit (usually taken from the DC bus) is normal.
- ● Try to restart the monitoring unit.
- ● Check whether the communication cables behind the monitoring unit connected to charging modules, insulation monitors, battery patrol instruments and other devices are securely connected.
- ● Verify whether system parameters (such as voltage alarm thresholds) have been accidentally modified.
6. Important Safety and Operation Reminders
- ● Professional Operation: The DC panel is a live device with risk of electric shock. All inspections must be performed by qualified professional electricians or technicians in strict accordance with safety operation procedures.
- ● Reference Drawings: During troubleshooting, it is recommended to analyze with the Electrical Schematic Diagram and Wiring Diagram of the DC panel to locate faults more accurately and efficiently.
- ● Prevention First: Regularly conduct check capacity tests on batteries, keep equipment clean, and tighten electrical connections — these are key to preventing faults and ensuring long-term reliable system operation.
- ● Seek Support: If the fault cannot be resolved through the above self-checks, or if it involves core components (such as damage to multiple charging modules, serious performance degradation of the battery pack, etc.), please record the fault symptoms and checked information immediately, and contact the equipment supplier or professional maintenance service provider for handling.
