Charger makes a loud clicking, buzzing, or humming noise during operation that is noticeably louder than when new.

Safety first: Unusual noises can indicate loose parts or impending failure. If the noise is accompanied by smell or heat, switch off immediately.

Steps to try:

• Compare with normal: Some clicking when starting/stopping is normal. Continuous loud buzzing is not.
• Power-cycle: Turn OFF and ON the charger to see if the noise persists.
• Listen for location: If safe from the outside, try to localise whether the noise is from the top, bottom, or side of the unit to help the technician.
• Technician inspection: A professional should open the charger, check that the contactor and transformers are firmly mounted, inspect for signs of arcing, and measure coil voltage. Replace the contactor or noisy component if necessary.