A Tesla clicking noise when charging is normal if you hear one click, or a click and a clunk, when charging starts and again when it stops. The click at the wall is the charger's relay switching power onto the cable; the deeper clunk is the car's high-voltage contactors connecting the battery. Tesla also lists pops, thumps and fan noise during charging as normal.
What is not normal is clicking that repeats over and over, especially if the charger's light drops out each time or charging keeps stopping and restarting. The rest of this page helps you tell the two apart and find which end the sound is coming from.
What makes each sound
Charging equipment (the Wall Connector and the Mobile Connector, known in the trade as EVSE) keeps its cable dead until the car asks for power. A relay inside does the switching. The car has its own set of contactors, heavy-duty switches that connect the high-voltage battery. Both make a mechanical sound when they close and open.
| Sound | Where it comes from | When you hear it | Normal? |
|---|---|---|---|
| Sharp click at the wall | Relay in the Wall Connector or Mobile Connector | Charging starts or stops | Yes |
| Deeper clunk from the car | High-voltage battery contactors | Charging starts or stops; also when the car wakes | Yes |
| Several quick clicks under the rear seat (older Model S) | Line and precharge relays in each onboard charger, per owners | Start of AC charging | Yes |
| Pop, thump or creak | Battery parts expanding and contracting | During charging | Yes, per Tesla |
| Hum or whoosh | Coolant pump, fans, A/C compressor | Battery heating or cooling | Yes, per Tesla |
| Rapid chatter or buzz | Relay or connection that cannot hold, or supply trouble | Throughout the session | No |
Tesla's Model Y owner's manual says sounds during charging are normal, particularly the refrigerant compressor and fan at high current. The Model S manual's list of normal operating sounds puts clunking, popping and thumping while charging down to metal components in the high-voltage battery expanding and contracting.
Battery contactors closing during charging
The contactor clunk is the sound most people notice. It is louder and lower than the charger's relay because the contactors are bigger switches carrying battery current. Tesla's manual describes the same contactor sound when you start the car after it has been parked.
Owners on Tesla Motors Club describe the pack as having two main contactors plus a smaller precharge relay. The precharge relay closes first to bring the voltage up gently, which is why some cars make a quick "clunk-clack" rather than a single sound. Plugging in can make the contactors go through a full close and open cycle, so you may hear more from the car when you plug in than when you get in to drive.
Why a Model S onboard charger clicks off and on
The classic Model S had a 40 A onboard charger with an optional second charger for up to 80 A, and from April 2016 the refreshed car got 48 A as standard with an optional 72 A unit. Owners report that each onboard charger has its own line relay and precharge relay under the rear seat. On a dual-charger car such as a 2014 Model S, that means more relays and more clicks at the start of each session, and each charger can switch separately.
If a 2016 Model S or older car clicks off and on repeatedly during a session, with charging pausing each time, that is not the normal startup sequence. Note the current on the car's charging screen when it happens, and see the checks further down.
Clunking at a Supercharger
DC fast charging bypasses the onboard charger, and owners report that two more contactors close for it. That is the extra clunk you hear a few seconds after plugging in at a Supercharger. Tesla's manual adds that the fans run to control battery temperature during Supercharging, which is why the car can sound like it is working hard. None of that points to a fault on its own.
Clicking while the car sits plugged in
A click or clunk from a parked car that is not charging usually means the car woke up. Owners report the contactors closing when the car wakes, for example to top up its 12 V battery. Anything that keeps waking the car makes this happen more often. In one TeslaFi community thread, owners found their contactors cycling roughly every two minutes and traced it to the app polling the car; revoking its access stopped it. Sentry Mode and apps that poll the car also cost range, which our page on vampire drain covers.
Clicking that points to a problem
The guidance in this section is general electrical practice rather than a Tesla statement. Treat the sound as a fault, stop charging and switch the charger's breaker off if you notice:
- Rapid chattering from the Wall Connector, like a relay that cannot stay closed.
- Clicks in time with the light bar dropping out, or charging stopping and restarting over and over.
- Buzzing from the charger, the breaker or the panel.
- Clicking together with a red light on the charger or a charging message on the car.
- Heat or a hot smell from the faceplate, the cable handle, an outlet or the breaker.
The likely causes are a loose connection (at the breaker, the Wall Connector terminals or a plug-in outlet), supply voltage problems, a failing relay or a fault that keeps retrying. Retrying is documented on the Gen 2 Wall Connector: after some faults it tries again every minute, or every 15 minutes for a ground fault, which can sound like a click on a timer. If your charger is showing a code, our page on the Wall Connector flashing red explains each one.
How to find where the clicking comes from
- Stand at the charger, then at the car. A sharp click from the wall is the charger's relay. A clunk from under the car is the car's contactors.
- Watch the light bar. If it stays steady green while charging and the clicks are occasional, the charger is fine. If it blinks out each time, note any red code.
- Read the car's charging screen. Watch the amps and voltage. Charging that keeps dropping to zero and restarting confirms an interruption.
- Lower the current. Turn the car's charge current down a few amps. If chattering stops, heat or a marginal connection is likely. Our guide to Tesla charger amps explains how the setting relates to the breaker.
- Try another charger. If the car clicks the same way on a Supercharger or a friend's unit, the car needs attention. If it is quiet elsewhere, look at your charger and circuit.
- Restart once. Cycle the breaker as described in our guide to power cycle the charger. If the clicking returns, stop there.
Who to call
- Clicking at the charger with heat, buzzing or a red code: a licensed electrician to check terminations, wire size and supply voltage. Tesla's manual requires 6 AWG 90 C copper at full power on a 75 C breaker, and a loose or undersized conductor gets hot under a long 48 A load. If an installer fitted your Wall Connector recently, start with them.
- Charger checks out, unit still chatters: Tesla support. The Wall Connector has a 48-month residential warranty from the invoice date.
- Clicks only from the car, at any charger, with charging interruptions: book a Tesla service visit and note the dates and times it happened.
Charging noise questions
Why does my Tesla click when it starts charging?
Two switches close. The Wall Connector or Mobile Connector has a relay that keeps the cable dead until the car asks for power, and the car closes its own high-voltage contactors to connect the battery. You may hear one sound from the wall and a deeper clunk from the car. The same pair of sounds happens in reverse when charging ends.
Is it normal for a Tesla to pop or thump while charging?
Yes. Tesla's owner's manual lists clunking, popping and thumping during charging as normal, caused by metal parts in the high-voltage battery expanding and contracting as it warms and cools. A pop paired with a fault message or charging stopping is a different matter.
Why does my Tesla click while parked and plugged in, even when not charging?
The car wakes up from time to time, and owners report it closing its contactors when it does, for example to keep the 12 V battery topped up. Apps that poll the car can wake it far more often. Owners using TeslaFi reported contactors cycling every couple of minutes until they stopped the polling. Check Sentry Mode and any third-party apps first.
Can the Wall Connector's relay wear out?
Any relay has a finite life, and a failing one can chatter or fail to hold. On a Gen 3 Wall Connector that would usually come with charging dropping out or a red fault code. Tesla's Gen 2 Mobile Connector even has a dedicated relay fault code. A unit within its 48-month residential warranty should go to Tesla, not to a repair shop.
Why is my Tesla louder when charging on a hot day?
Tesla says the refrigerant compressor and fans can run during charging, especially at high current, to keep the battery at its preferred temperature. On a hot day the cooling has more work to do. It is a hum or whoosh rather than a click, and it fades as the battery reaches its target temperature.
Sources
- Tesla Model Y owner's manual: Charging instructions (sounds during charging), tesla.com
- Tesla Model S owner's manual: Normal Operating Sounds, tesla.com
- Tesla service: Gen 2 Mobile Connector status lights (relay fault code), service.tesla.com
- Tesla Gen 2 Wall Connector installation manual (auto-retry behavior), digitalassets.tesla.com
- Tesla Motors Club: Identifying contactor clicks, teslamotorsclub.com
- TeslaFi community: Why are my HV battery contactors cycling every 2 minutes?, support.teslafi.com
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