504

Overcurrent on DC side (Battery)

Fronius · Primo GEN24

What does 504 mean?

The Fronius Primo GEN24 208-240 inverter has detected an excessive current flowing to or from the connected battery system on the DC side. This indicates a potential short circuit in the battery DC wiring or an issue with the battery itself.

Common Causes

  • Overcurrent on the DC side (battery).
  • Short circuit on the battery connection.
  • Internal fault in the battery system.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Disconnect the battery using the DC disconnector and visually inspect all battery cables, terminals, and connectors for signs of damage or short circuits.

  2. 2

    Check the battery's operating status and any error indicators on the battery itself. Consult the battery manual.

  3. 3

    Measure the voltage at the battery terminals to ensure it is within the normal operating range.

  4. 4

    Verify that the DC cables connecting the battery to the Fronius Primo GEN24 208-240 inverter are correctly sized and free from insulation damage.

  5. 5

    If the battery system permits, check for internal fault codes or diagnostics within the battery management system (BMS).

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Verified technical data. Last updated: March 2026

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