24

Battery Too Hot (External Sensor)

Fronius · Perfect Charging

What does 24 mean?

The external temperature sensor indicates that the battery temperature is excessively high. This is a critical safety condition that requires immediate attention to prevent thermal runaway, battery degradation, or potential hazards such as fire.

Common Causes

  • High ambient temperature around the battery, leading to increased overall temperature.
  • Excessive charging current applied to the battery, generating internal heat faster than it can dissipate.
  • Malfunction of the battery's internal cooling system (if equipped) or an issue with the external temperature sensor mounting.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the ambient temperature surrounding the battery and ensure adequate ventilation.

  2. 2

    Reduce the charging current, if adjustable, or temporarily pause the charging process to allow the battery to cool down.

  3. 3

    Ensure the external temperature sensor is properly attached to the battery surface at the recommended location for accurate temperature measurement.

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Verified technical data. Last updated: March 2026

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