Knocking sound from battery pack?

Knocking sound from battery pack?


This happend to me twice now, will climbing big hill for several minutes. I did heard knocking / banging / popping sounds from random spots from the floor / battery pack.

At first I was thinking the rocks was hitting the underneath of the car but it also happened on newly paved and clean roads. And I can feel it under my feet when it did append on the front and driver side of the floor.

The sound occur from time to time, Once every 45 sec or so.
I really sound like something was this the floor hard.
Temperature was around -1 Celsius
Hill was about range between 6% and 8%

Any idea?

garretn | 31 oktober 2018

I have the same noise but only when Supercharging the car but I have read others have heard the knock or thud while driving. I was at my service center last week and they had never heard of this before. I think we need to start making them aware of this so if something is going on with the battery pack it gets addressed.

If you search the forum you will find some threads on this matter.

Bighorn | 31 oktober 2018

It’s thermal or physical flexion of a metal plate. Loudest whike supercharging when it’s cold out. Oil canning is one description I like.

PaceyWhitter | 31 oktober 2018

Bighorn is probably right, but maybe, in their rush to ramp up production, they actually trapped a worker in the battery. If so, touched should let them out.

fpugliese3 | 31 oktober 2018

@paceywhitter....if you free him you will get three wishes.

vishious911 | 31 oktober 2018

After ~2500 miles and 3 months of ownership of the LR-RWD, I heard a bang sound the first time from under the car this weekend. I couldn't feel anything and wasn't sure if my tire burst or if it was something else.

I was driving about 70-75mph on a freeway then. So I opened up the TPMS window on the car, and was monitoring it along with just any general warnings on the car. None whatsoever. So I kept driving, and seems fine so far. Besides this just one occurrence.

Carl Thompson | 31 oktober 2018

The sound of individual battery cells exploding? ;-)

Sparky | 31 oktober 2018

I've heard this sound as well. But I just play "Can't You Hear Me Knockin'" by the Rolling Stones. Turned up to 11 it masks it very well.

brianblocher | 31 oktober 2018

Almost daily while climbing a hill on the way to work I get a clank from battery. Some sort of pressure release valve from the heat?

Morrobay805 | 1 november 2018

I hear a knocking sound from under the vehicle when I unlock my car, I wasn't sure if it was some sort of anti theft device. Any ideas?

Bighorn | 1 november 2018

Probably contactors/relays hooking up power.

Bighorn | 1 november 2018

Hasmd a good discussion at a service center with an advisor and the clunk is not on Tesla’s radar yet. No bulletins or even local knowledge on this phenomenon. With winter coming and the volume of deliveries, it soon should be.

Bighorn | 1 november 2018


Sparky | 1 november 2018

It would be nice to know if it is the battery case metal flexing or internal relays in the pack.

Carl Thompson | 1 november 2018

The contactor clunk is a different thing I think. I think it's normal to hear that whenever the car is woken up (via unlock, connecting via the app, etc). But you wouldn't / couldn't hear that when driving the car (unless something is very, very wrong).

kevin_rf | 1 november 2018

Was wondering what it was, had a light thunk under the brake pedal a few times times when I let off the gas. Was wondering if it was a bad engine mount for the AWD... about the right place.

Samta09 | 1 november 2018

I hear it in the morning when the car wakes up and when charging it at Superchargers.

walnotr | 1 november 2018

I had heard the sound awhile back but the last several times I have charged it has not been heard. The only variable I can come up with was the ambient temperature. When heard it was in the low forties. It has been warmer than that during charging the last 6 or so times and have not had a repeat of the sound. One caveat, I have not always been the car for the full charge cycle but most of them.

Bighorn | 1 november 2018

It’s absolutely not a relay. The 3 has a very tinny floor. It does not have as robust a frame and the battery is a structural necessity, where the S and the X it is not. A Model 3 can not be moved with the battery removed. Some people may be referring to different normal sounds they we’ve learned from having the Model S, but this is a unique, loud and startling sound that is a metal plate flexing.

Bighorn | 1 november 2018

Lower temps definitely accentuate it.

leo33 | 1 november 2018

A few weeks ago I sent my service center an email mentioning the pops, rattles & oil can sounds under the floor but have not heard back. They probably think I'm crazy now. I wonder how things get onto their radar.

brianblocher | 1 november 2018

It’s like clockwork. Happened again today, same hill and same spot on the hill.

Mblaze76 | 11 november 2018

I’ve heard it while charging at the super chargers but now it’s happening when I’m driving. It is getting colder here in the Chicago burbs so maybe temp has silething to do with it.

Bighorn | 11 november 2018

Thermal and mechanical flexion. Damper in the works.

garretn | 12 november 2018

During my last visit to the service center I discussed this with the shop foreman that by the way owns and drives a model 3. He had no knowledge of any noises that were not cooling system noises or high voltage relays. What he told me to do was when this happens write down the time and date and they could look into it and see what is taking place at that time.

Sasquatch2001 | 12 november 2018

I heard the noise when we tried a supercharger for the 1st time this weekend... JFC those things charge fast! 100mi in 20 minutes?

Jeffjaslow | 12 november 2018

I too went up I70 to Breckinridge to go skiing. First thump was around Evergreen, thought I hit something on the road. First, knock was under the car in the middle. As I progressed up the mountain 5 more knocks sounded as if the struts springs were popping into place...then as I parked in the heated garage a metal popping sound came from the front left of the car while not moving or charging.

Spent an hour on hold for the service center in SLC to get to me in que...recorded the 4 times it clunked on the way down the mountain and asked if there was any knowledge of this occurring to other M3s and was told NO. Asked if there were any alerts on my car and again was told no. She advised right when the clunking sound occurs to send a bug report, by pressing the mic button and sayings bug report. She said that this will flag the time and if anything is available for the technicians to trouble shoot.

Please call this in if it occurs so that Tesla can address...THANKS for this thread!

Bighorn | 12 november 2018

@garret and Jeff
There's nothing for the car to record--it's a flexing piece of metal. Lots of service staff people are still ignorant to the issue, but not all of them. Tesla is working on a fix.

LostInTx | 12 november 2018

I've heard a similar thump / clunk sound right when I get in the car and touch the brake for the fist time. In my case, the even is always accompanied by the UI rebooting.

Bighorn | 12 november 2018

Clunks of the contactor are normal--random, loud bangs are what we're talking about being novel.

Patrick | 12 november 2018

I get the heavy “clunk” sound every time I unlock and wake the car. Assume it’s a high voltage contactor activating in prep for go mode. So far no random loud bangs. Its still warm in FL... | 12 november 2018

Aluminum contracts more per degree K at subfreezing temperatures than steel or titanium. If the battery pack case is made of Aluminum and you start out in a garage with temp. substantially higher than outdoors, the Aluminum panels will shrink as you drive and the battery pack case cools down. Properly design will accommodate this but they may not have allowed enough for the shrinkage. One could imagine it being enough to pop some rivets that would make a noticeable ding hitting the floor. This is all speculation but it sounds like the battery case may not have been designed with adequate tolerance for cold weather.

bthaqi2 | 12 november 2018

Sounds like a serious problem! Please let us know how you make out. Thanks for sharing this info.

Bighorn | 12 november 2018

Not a serious problem at all.

walnotr | 12 november 2018

While Tesla’s are not aircraft, most airplanes are made from aluminum and go from sea level to 30000+ feet in a matter of minutes where the outside temperature is -40 to -60F. I have not seen spot welds or rivets pop because of those cold temperature extremes. I seriously doubt our cars are popping welds or rivets at 40F or even -20F.

gwolnik | 12 november 2018

Have you tried using a higher octane fuel? :) | 12 november 2018

@walnot: good point. Aircraft surfaces experience large temperature variations up and down as well as exposure to mechanical stress. | 12 november 2018

@walnotr that is.

Bighorn | 12 november 2018

Rivets are not popping.

transaxl | 12 november 2018

I hear what sounds like a clunk and metal shifting; I can feel a physical jolt through the floor. This happens when going up or down steep hills. M3 delivered last week. It feels like it comes from the front left or rear left of the car.

bthaqi2 | 13 november 2018

Bighorn - have you had this problem in your model 3? If so how was it addressed? From your postings you sound confident what the problem is. Thanks

Bighorn | 13 november 2018

I've experienced the noise at least 100 times, mostly while supercharging, but also pulling into parking lots. We've crowdsourced an answer that Tesla has been slow to appreciate. Most service centers seem not to be aware of the issue. A knowledgeable ranger recently let a customer know that a solution is in the works. Basically, what's thought to be a metal floor plate above the battery needs some sort of dampener to keep it from flexing and making the oil can sound.

jcd82 | 13 november 2018

so the flufferbot was needed after all!?!?!?!

Bighorn | 13 november 2018

That's been surmised:)

BlueMeanie | 13 november 2018

2,900 miles on my LR - heard the popping / thuds for the first time this weekend while driving in the Smoky Mountains. High 30's, low 40's degrees F. Noticed up and down hills.
Could feel it in the floor, some louder than others.
Haven't noticed again since leaving the mountains.

bthaqi2 | 13 november 2018

So hopefully there will be a recall to fix this issue! I wouldn't want those loud bangs scaring my kids from below while driving. While supercharging I wouldn't get worried to much. Thanks

Jeffjaslow | 13 november 2018

Just found out how to escalate these issues to management online:

1. Login to
2. Click Manage
3. Click Ask A Question
4. Fill
5. Click escalate to management
6. Submit

This forum is great to see if others are having similar experiences, but giving Tesla management an idea of how many people are experiencing this issue will help them prioritize the fix.

Bighorn | 13 november 2018

There won’t be a recall per se, but likely a bulletin which may or may not require a customer instigation. Similat to how the loud AC compressor could get an acoustic blanket, but you had to request it.

joseph.eschbach | 18 november 2018

I have the same problem and it's getting worse. I live at the top of a fairly steep long hill. In a period of 2 miles, I go up about 800 feet of elevation. The last hill is the steepest before my house and I regularily hear knocking sounds. Bought car Aug 31. Dual motor. Perhaps colder weather is contributing, but I only hear it after the steep incline. Service center in Seattle didn't seem to know it as an issue.

Bighorn | 18 november 2018

I’m thinking it’s the battery heat on hills rather than an elevation change. Definitely worse in colder weather.

Jim Little | 18 november 2018

I can confirm this. Picked up M3 Dual Motor extended range on Friday. Drove 200+ highway miles on way home. Supercharged briefly and heard the clicking sound from battery. Then drove over a mountain pass 3500 feet, 20-30 degrees ambient temps. Had loud "banging" sound coming from under car. Sounded like ice coming hitting inside of the wheel wells or bottom of the car, but roads mostly dry. Did same mountain pass twice today, roads totally dry, still same banging noise going up and during regenerative braking down. This is NOT same sound as supercharging in my admittedly limited experience.