Zaptec Noisy Contactor or Relay

Charger makes a loud clicking or buzzing noise during operation, even when not actively 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 vibrating main contactor, Loose mounting of contactor, Coil voltage instability, Defective relay on control board

How to Fix / Troubleshooting

Safety first: Turn off power before touching the charger enclosure or opening it.

Steps:

  • Observe pattern: Note whether the noise occurs only at start/stop or continuously.
  • Power-cycle: Turn the breaker OFF for 2 minutes, then ON, and listen if the noise returns immediately.
  • Technician inspection: With power off, open the unit and check that the main contactor is firmly mounted and not loose. Inspect for signs of overheating.
  • Replace component: If the contactor or relay is mechanically noisy or chattering due to coil issues, replace it with a Zaptec-approved part.
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Repair Difficulty

Hard 4/5

Required Part

Main Contactor
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