Electric Cars
EV Makes a Humming Sound When Parked
The car hums, buzzes or clicks while sitting parked or charging, with no one inside.
What causes it
Battery cooling, the 12V charger, pumps and HVAC systems all run periodically - normal behavior.
Why it happens
- Battery thermal management - the car cools/warms the pack even when parked, especially after a drive.
- 12V battery charging - the DC-DC converter tops up the 12V battery periodically.
- HVAC cycling - cabin preconditioning or battery heating.
- Contactors clicking when the car wakes for an update.
What to do
- It's normal - EVs wake up briefly to run housekeeping tasks.
- Check the app for activity - some cars show when they're managing the battery.
- If it's constant, loud, or smells hot, that's unusual - book a service.
- To reduce activity - disable features like remote climate and cabin preheat in the settings.
Good to know
Some EVs run the fan after fast charging for 10-20 minutes to cool the battery - that's by design and worth knowing so you don't worry.