Battery communication lost during backup

What does 904 mean?

The Fronius Primo GEN24 208-240 inverter has lost communication with the connected battery system while operating in backup power mode. This critical failure prevents the inverter from managing battery power, leading to a backup power shutdown.

• Battery communication lost during backup.
• Communication cable fault.
• Battery system fault.

Click steps to track your progress.

1. 1

   Verify all communication cables between the Fronius Primo GEN24 208-240 inverter and the battery management system (BMS) are securely connected and free from damage.

2. 2

   Check the battery system's status indicators and internal diagnostics for any faults related to its communication module.

3. 3

   Ensure the battery system remains powered on and operational, as a battery shutdown will also cause communication loss.

4. 4

   If the system allows, perform a controlled shutdown and restart of both the inverter and the battery system to re-establish communication.

5. 5

   If the fault persists, this may indicate an internal communication hardware fault in either the inverter or the battery; contact Fronius service or battery supplier.