Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Random Subsonic Boom or Bang

rjpjnk

Active Member
Mar 12, 2021
1,015
623
NJ
Anyone else hearing these random subsonic BOOMs while sitting quietly parked with HVAC running (camp mode)?

When it's happening it is one boom every few minutes or so, and I never know when it will act up. I would say It is more felt than heard. It is a very low frequency impulse that sounds like an explosion somewhere nearby shaking the ground. After the initial impulse I believe I can hear a brief rush of fluid or gas for second.

I've been following this for a few weeks now to try to determine under what conditions it happens but nothing conclusive yet. I did notice that by changing the temperature setting on the climate control I was able to make it stop a couple times, so I suspect it is related. Perhaps some sort of pressure release from the heating/cooling system?

I've read about the accounts of noises from the battery case expansion/contraction, but I don't know if that would account for the associated fluid sound. It sounds like a burst valve is opening to blow off pressure somewhere.
 
  • Like
Reactions: KenYoung1

Cavity

Member
Nov 19, 2021
12
5
Florida
Not sure about the "booms", you might want to have that checked out, but...

•In addition to cooling the interior, the air conditioning compressor also cools the Battery. Therefore, in hot weather, the air conditioning compressor can turn on even if you turned it off. This is normal because the system’s priority is to cool the Battery to ensure it stays within an optimum temperature range to support longevity and optimum performance. • Even when not in use, you may hear Model Y emit a whining noise or the sound of water circulating. These sounds are normal and occur when the internal cooling systems turn on to support various vehicle functions, such as maintaining the 12V battery and balancing the temperature of the high voltage Battery.

I think there's another section that referenced noises emanating from the HV battery, I'll have to check when I have more time.
-Cheers
 
The loud bangs are likely the battery pack contactors cycling (like switches). This is normal operation of the high voltage battery.

However, it should not be happening 1 per minute constantly. More like, one per 20 to 60 minutes. If it's really happening one per minute (and you're not using hyperbole) then you should probably have service look at it.
 

rjpjnk

Active Member
Mar 12, 2021
1,015
623
NJ
When it’s in the mood to happen it really is about once per minute, maybe even 2 or 3 times per minute. Then it goes away as mysteriously as it started until it feels like coming back. The problem with taking it into service is I cannot reliably reproduce it.
 

iamnid

Member
Dec 4, 2019
829
852
Riverside, CA
Why do you suspect it’s the compressor?
Because, in mine at least, that's exactly what it is. I noticed it the most in the summer when I'd sit in a parking lot. The air would be blowing and, periodically, the compressor would start up to cool the air when the temp rose, and I'd feel/hear the very low rumble. Try rolling your window down to see if you can hear it better.
 

rjpjnk

Active Member
Mar 12, 2021
1,015
623
NJ
…and I'd feel/hear the very low rumble. Try rolling your window down to see if you can hear it better.
What I’m hearing is not a rumble. It is a single impulse. I do suspect it may be related to the HVAC system though. I took out the frunk liner and felt and listened to the compressor and didn’t hear anything unusual, but the booms were not happening that day. I do suspect that system.
 

gx9901

Member
Aug 1, 2021
128
195
St Paul, MN
I've noticed this sound maybe a month and a half ago. There was a thread here describing it as a "Whoosh" sound, but nobody had anything conclusive. I too noticed that it was occurring around once every minute. While it kind of sounded abnormal, I decided it wasn't intrusive enough to dive deeper into it and thought I'd just deal with it later if it manifested itself as some sort of a problem. Lately I have not noticed this sound, but it could just be that it didn't catch my attention. Anyway, I don't have anything to add regarding this issue other than to say I've heard it on my car as well, when nothing besides the HVAC is on.
 

Etna

Member
Jan 31, 2017
398
6,030
Québec City
Same here, exactly as you describe. A very low frequency "thump" that you can nearly feel in your body, always promptly followed by an exhalation (like a whoosh) from the front air vents for a second or two. Nothing to do with compressors or contactors which make entirely different and distinct noises.

It does not bother me generally, but it does annoy the hell out of me when I try to fall asleep in my car. It basically ruins my camp mode experience. Happens every minute or two, but sometimes it doesn't at all.

I am also hearing it occasionally when I drive at very low speed with no wind noise, or stopped at a light.

Next summer I will be doing more camping in my car so I will be watching this thread for sure. I am glad @rjpjnk brought this up.
 
  • Like
Reactions: rjpjnk

rjpjnk

Active Member
Mar 12, 2021
1,015
623
NJ
Same here, exactly as you describe. A very low frequency "thump" that you can nearly feel in your body, always promptly followed by an exhalation (like a whoosh) from the front air vents for a second or two. Nothing to do with compressors or contactors which make entirely different and distinct noises.
Yes!!! Exactly this. I am so glad someone else recognizes it. A low frequency impulse followed by a faint "exhalation". Good word for it!

I agree it kind of ruins Camp Mode. It makes it difficult to take a nap in the car because it is startling. I doubt it is of any concern otherwise.

I think the boom frequency may be too low to record unless I can get a good microphone with some sensitivity in the 20-30 Hz range.

I will continue to monitor this. If you learn anything additional about it please get back to me. Thanks.
 
  • Like
Reactions: Etna

Pianewman

2021 MYLR VIN 88,XXX, Rd/Wh, 12/20 delivery
Oct 28, 2020
1,702
1,233
Fort Worth
VIN 88xxx, 19k miles. I've been annoyed by the low ffrequency rumble of the HVAC since the beginning (Dec. 2020 delivery), and lately, I've noticed the low-frequency "thump" that y'all are talking about.

Didn't notice it in ambient 80-95f temps, HVAC set to 70-72.

Ambient temps now 45-75, HVAC set to 70. Cooler temps require a different cycling of the HVAC components.
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top