404

Inverter with battery: no communication

Fronius · Primo GEN24

What does 404 mean?

The Fronius Primo GEN24 208-240 inverter, configured to operate with a battery, has lost communication with the battery system. This prevents any battery charging or discharging, effectively disabling the energy storage function.

Common Causes

  • No communication with the battery.
  • Wiring fault (e.g. incorrect or loose cable, crossed data lines).
  • Battery not powered.
  • Incorrect battery address or settings.
  • Battery system internal fault.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check all communication cables (e.g., CAN bus, RS485) between the Fronius Primo GEN24 208-240 inverter and the battery management system (BMS) for proper connection and integrity.

  2. 2

    Confirm that the battery system is powered on, not in sleep mode, and its status indicators (LEDs) are normal.

  3. 3

    Verify the communication protocol settings (e.g., CAN ID, Modbus address) within the inverter's interface align with the battery manufacturer's specifications.

  4. 4

    Inspect the communication cable for any physical damage, breaks, or incorrect pinouts.

  5. 5

    Perform a controlled shutdown and restart of both the inverter and the battery system as per their respective manuals to reset communication.

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Verified technical data. Last updated: March 2026

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