BYD Mechanical Vibration / Coil Buzz in Contactor or Transformer

Charger makes loud buzzing or humming noises during operation, louder than usual, without showing an error code.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Aging or loose main contactor, Loose mounting screws on power module or transformer, Resonance in enclosure panels, Slightly undervoltage coil supply

How to Fix / Troubleshooting

Safety first: Turn off power before touching or tightening any internal components.

  • Identify source: Listen closely (from a safe distance) to determine if the noise comes from the top, bottom, or side of the BYD charger.
  • Check mounting: Ensure the charger is firmly fixed to the wall and not vibrating against loose siding or panels.
  • Professional internal check: A technician can open the unit, tighten mounting screws on the contactor, power module, and any internal transformer.
  • Monitor for heat or smell: If buzzing is accompanied by overheating or burning smell, stop using the charger and have it serviced immediately.
  • Replace noisy contactor: If the contactor coil is buzzing excessively, replacement is recommended.
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Repair Difficulty

Medium 3/5

Required Part

Main Contactor Relay
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