How to Fix / Troubleshooting

Safety first: Overheating can lead to fire. Allow the unit to cool before opening.

Steps:

Check installation location: Ensure the Walli charger is not installed in direct sun without shading, or in a confined space without airflow. Clear any objects blocking vents.
Inspect for heat damage: With power off, open the housing and look for discoloration around power terminals, busbars, and the contactor. Tighten any loose connections.
Verify cable sizing: Confirm that the supply cable and breaker are correctly sized and that the charger current limit is not set above its rating.
Monitor temperature via app: Some Walli models report internal temperature. If temperature rises rapidly at low load, the internal sensor or board may be faulty.
If E09 recurs under normal conditions: Replace the Walli main control board or the temperature sensor module as specified by the service documentation.

Walli charger displays E09; app shows 'Temperature too high' and charging stops.

Possible Causes