How to solve Error Code 29

Fault code:

【29】Alarm for battery capacity rate below 10% (effective after successful BMS communication)

Reason:

The energy storage inverter triggers an alarm when the battery capacity rate is below 10%, usually related to the remaining capacity monitoring and protection mechanism of the battery. BMS (Battery Management System) monitors the SOC (State of Charge) or remaining capacity of the battery and triggers an alarm when it falls below a preset threshold.

1. SOC threshold set too low

Inverters are usually equipped with SOC low threshold protection, which triggers an alarm when the remaining capacity is below this value. Check the SOC threshold setting in the equipment manual and adjust it to a higher value (such as 15% -20%) if necessary.  ‌

2. BMS communication abnormality

If BMS fails to communicate with the inverter, it may result in false alarms. It is necessary to check whether the CAN bus connection is normal, whether the DBC file configuration is correct, and ensure that parameters such as baud rate are consistent.  ‌

3. Battery aging or abnormal discharge

After the end of the battery cycle life or deep discharge (such as exceeding 80% DOD), capacity degradation may occur. It is recommended to check the number of battery cycles (usually about 500 for lead-acid batteries and about 1000 for lithium batteries) and replace the battery if necessary.  ‌

4. Parameter calibration issue

If the inverter parameters are not adjusted according to the actual battery capacity (such as the maximum charging and discharging power not matching the battery capacity), it may cause overload protection to trigger. Need to recalibrate parameters or consult technical support‌

Solution:

1. Verify BMS communication

Check whether BMS data is transmitted normally through CAN bus tools (such as USBCANFD200U), and confirm whether the baud rate (usually 250Kbps) and variable offset are accurate.  ‌

2. Check SOC threshold

Check the SOC low threshold in the inverter settings, and if it is lower than the actual demand, adjust it to a reasonable range (recommended 15% -20%).  ‌

3. Calibrate battery parameters

Confirm that the maximum charging and discharging power of the inverter matches the battery capacity to avoid false alarms caused by improper parameter settings.  ‌

Note: Please do not dismantle the machine without permission, otherwise it will be out of the warranty of Ktech.