Mini Excessive Electrical or Mechanical Noise from Contactor or Power Module

Mini EV Home Charger makes loud buzzing or humming noises during charging

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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

Worn or loose power contactor, Loose mounting screws on transformer or inductors, High mains voltage causing magnetostriction noise, Resonance in enclosure panels

How to Fix / Troubleshooting

Note: Some low-level hum is normal; sudden loud noise is not.

  • Identify source: Stand near the charger while it operates and localize the noise (top, bottom, left, right). Do not open the unit while energized.
  • Check mounting (technician): With power OFF, remove the cover and tighten mounting screws for the contactor, transformers, inductors, and the enclosure backplate.
  • Inspect contactor: If the contactor vibrates excessively or chatters, replace it with a Mini-approved part.
  • Verify supply voltage (electrician): Ensure mains voltage is within specification; overvoltage can increase noise.

Persistent loud buzzing may indicate impending component failure and should be addressed promptly.

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Repair Difficulty

Medium 3/5

Required Part

Mini EV Charger Power Contactor / Relay Block
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