Walli charger displays E25; app shows 'Isolation fault' or 'Insulation resistance too low'.

Safety first: Low insulation resistance can lead to shock or fire. Do not use the charger until resolved.

Steps:

• Visual inspection: Look for water, condensation, or corrosion inside the Walli housing and around the cable entry and connector.
• Drying: If moisture is present, disconnect power and allow the unit to dry thoroughly. Use gentle airflow; do not use high heat.
• Insulation test (technician): With the charger disconnected, perform an insulation resistance test between each output conductor and earth. Values below manufacturer limits indicate a fault in the cable or internal wiring.
• Replace affected parts: Replace the Walli cable assembly or internal wiring harness if insulation is compromised. If wiring is sound but E25 persists, replace the insulation monitoring circuit or main control board.