What to do if Huawei SUN3KTL-L1 Inverter displays Grid-tied/Off-grid Controller Abnormal?
- JJoshua DavisSep 23, 2025
If your Huawei Inverter displays a Grid-tied/Off-grid Controller Abnormal message, it means the inverter isn't communicating with the Smart Backup Box. Follow these steps: 1. Send a shutdown command on the app. Turn off the AC output switch, DC input switch, and battery switch. 2. Check whether the power cable and RS485 cable between the Smart Backup Box and the inverter are normal. 3. After 5 minutes, turn on the battery switch, AC output side, AC output switch, and DC input switch.









