300
Temperature Sensor Connection Failure
Fronius · Perfect Charging
What does 300 mean?
The battery charger was unable to establish a connection with the temperature sensor. This prevents the charger from monitoring crucial temperature data, which is essential for safety and optimal charging performance.
Common Causes
- A disconnected or damaged wiring between the charger and the temperature sensor.
- A faulty temperature sensor that is not responding or providing a valid signal.
- Incorrect wiring or improper termination of the sensor connection at the charger's input terminals.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Verify the physical connection and wiring integrity of the temperature sensor, ensuring it is securely connected to the designated terminals.
- 2
Measure the resistance of the temperature sensor across its terminals and compare it to the expected resistance values for its ambient temperature.
- 3
Check the sensor's terminal connections on the charger for proper seating and absence of corrosion.
Verified technical data. Last updated: March 2026
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Source: Fronius Perfect Charging