The Battery Management System (BMS) is critical to ensuring the safe operation, performance and longevity of batteries. However, the BMS can malfunction for a variety of reasons. The following are some common BMS failures and troubleshooting methods:

1. System does not work after power on

Common causes:

- Abnormal power supply.
- Wiring harness is shorted or disconnected.
- No voltage output from DC-DC converter.

Troubleshooting Steps

- Check whether the external power supply is normal and meets the minimum operating voltage required by the BMS.
- Ensure that the external power supply does not have a current limit setting that restricts power to the BMS.
- Check the wiring harness for shorts or breaks.
- Check DC-DC converter for voltage output and replace if necessary.

2. BMS fails to communicate with ECU (Electronic Control Unit) **Common Cause:** BMS fails to communicate with ECU (Electronic Control Unit)

Common cause:

- BMU (main control module) does not operate.
- CAN signal line is disconnected.

Troubleshooting procedure:

- Check whether the power supply (12V/24V) to the BMU is normal.
- Check the CAN signal transmission line and connector for problems and make sure that packets can be received.

3. Communication between BMS and ECU is unstable.

Common causes:

- Poorly matched external CAN bus.
- Bus branch too long.

Troubleshooting Steps:

- Verify that the bus matching resistors are correct.
- Ensure that the match is in the correct position and that the branch is not too long.

4. Erratic internal BMS communications

Common Cause:

- Loose communication line plug.
- CAN alignment is not standardized.
- BSU address duplication.

Troubleshooting steps:

- Check whether the connection of the communication line is loose.
- Ensure that the CAN alignment is standardized.
- Verify that the BSU address is unique.

5. Acquisition Module Data Zero

Common Causes:

- Acquisition line disconnected.
- Acquisition module is damaged.

Troubleshooting Steps:

- Reconnect the collection line.
- Test the functionality of the collection module and replace if necessary.

6. Battery temperature difference is too large

Common Cause:

- Loose cooling fan plug.
- Faulty cooling fan.
- Temperature probe damaged.

Troubleshooting Procedure:

- Reconnect the cooling fan plug.
- Test cooling fan function.
- Check the actual battery temperature and measure the internal resistance of the temperature probe.

7. Unable to charge with charger

Common Cause:

- Communication problem between charger and BMS.

Troubleshooting Steps:

- Use a replacement charger or BMS to verify that the problem is with the charger or BMS.

8. SOC (State of Charge) Abnormal

Common Cause:

- Current sampling is not calibrated correctly.
- Current sensor type does not match host program.
- Battery has not been charged and deeply discharged for an extended period of time.

Troubleshooting Procedure: Recalibrate the current sample.

- Recalibrate current sampling.
- Make sure the current sensor type matches the host program.
- Perform a deep charge/discharge cycle on the battery.

9. Battery current data error

Common causes:

- Hall signal wire plug is loose.
- Hall sensor damaged.
- Acquisition module is damaged.

Troubleshooting Procedure

- Reconnect the Hall signal wire.
- Check the Hall sensor power supply and signal output.
- Replace the acquisition module.

10. Battery temperature is too high or too low

Common Cause:

- Loose cooling fan plug.
- Faulty cooling fan.
- Temperature probe damaged.

Troubleshooting Procedure:

- Reconnect the cooling fan plug.
- Test cooling fan function.
- Measure internal resistance of temperature probe.

11. Insulation Monitoring Failure

Common causes:

- Power cell system is deformed or leaking.

Troubleshooting procedure:

- Check if the power cell system is deformed or leaking.
- Make sure the insulation monitoring sensor is working properly.

General Troubleshooting Methods

- Observation method: Check the alarm or error icons on the display and investigate each problem.
- Troubleshooting method: Disassemble parts one by one to find the problematic part.
- Replacement method: Replace the module to determine whether the problem is with the module or the wiring.
- ENVIRONMENTAL CHECK METHOD: Check basic factors such as power supply, switch status, and connections.
- Program Upgrade Method: Compare the program with the previous version to find out the problem.

By understanding these common failures and following the troubleshooting steps, you can effectively diagnose and resolve BMS issues to ensure safe and efficient operation of your battery system.