Bosch EV charger makes a faint high-pitched whine during operation, especially at higher currents.

Safety first: Do not open the charger while energized.

• Assess severity: A faint whine that does not change abruptly and is not accompanied by overheating or errors is often normal for switching electronics.
• Check mounting: Ensure the charger is firmly attached to the wall to reduce resonance.
• Monitor temperature: Confirm the unit is not excessively hot during operation. If it is, stop using it and call for service.
• Service if abnormal: If the noise becomes loud, changes suddenly, or is accompanied by burning smell or errors, a technician should inspect internal inductors and capacitors for damage.