Loud Regen Braking Noise (Cold Battery)

[rorrim]

Hi Everyone,

I was wondering what your experiences are with regen braking noise in your Model Y? I have always felt mine was louder than normal, but now that's it's cold out, I've noticed that it produces a high pitched squealing sound when slowing down, especially at higher speeds. Since regen doesn't work well when the battery is cold, the car slows down gradually when releasing the accelerator pedal and the sound lasts for the entire time the car is slowly reducing speed. This is most apparent when regen is activated at higher speeds (especially on the highway). Does anyone else have a similar experience? I've tried to capture a video (link, below) but the mic is having a tough time picking up the sound...

Link (turn volume way up...Listen for high frequency sound):


Appreciate any feedback you can provide!

 

[Tim42069]

Having the same issue....mobile service said they’ve never heard of this, and suggested I open another request with the service center.

Sound also increases when navigating to a supercharger. My Model 3 was dead silent in comparison.

 

[rorrim]

Here's the missing link from my original post:

https://photos.app.goo.gl/86Wx6VMEnpgRbzEk6

 

[rorrim]

Having the same issue....mobile service said they’ve never heard of this, and suggested I open another request with the service center.

Sound also increases when navigating to a supercharger. My Model 3 was dead silent in comparison.

Thanks for the quick response. Good to know that the Model 3 you had was silent.

 

[Eriamjh1138]

Is it an electric whine or a mechanical squeal? Because an electrical regen whine makes so sense. It HAS to be mechanical.

 

[rorrim]

Is it an electric whine or a mechanical squeal? Because an electrical regen whine makes so sense. It HAS to be mechanical.

I can’t tell if it’s mechanical or not. It’s a high pitch whine and doesn’t sound like it should be normal. I’d expect reduced braking when cold without the noise being present.

 

[Eriamjh1138]

Either way, I doubt it’s “in spec”. Take it in.

 

[rorrim]

Either way, I doubt it’s “in spec”. Take it in.

Yup, agreed. Just wanted to check what others experiences are now that it’s colder out before I go through the hassle of bringing it into an SC. I wonder if mobile service could do a first pass check on it?

 

[Tim42069]

Mobile service couldn’t do an assessment as they’re apparently not allowed to test drive due to COVID. Re-booked with service center.

This is definitely an electrical whine.

 

[meh_]

I noticed your regen was super reduced (due to cold I assume). Does it make the same noise when it is preconditioned and warm?

 

[rorrim]

I noticed your regen was super reduced (due to cold I assume). Does it make the same noise when it is preconditioned and warm?

For me, it’s always been loud and doesn’t sound quite right, but it’s much worse with colder temps and reduced regen. Is this normal under these conditions?

 

[meh_]

I don't hear any noise out of mine. But I've also never had that many regen dots

 

[rorrim]

I don't hear any noise out of mine. But I've also never had that many regen dots

Anyone living in colder climates have any experience with regen noise when battery is cold?

 

[Infarction]

I have this exact same issue with my new Tesla Y as well. I changed the mode from hold to the one in the middle which helped a bit. VIN 94xxx. I also notice the sound more when I am sending my Tesla to a supercharger and the battery says it is preparing for supercharging while I am driving. I have a service appointment for this issue as well but it’s not until later so I’m really interested to find out what they end up telling you guys is the cause of this high pitched sound

 

[Big Earl]

What’s that sound?

When the battery is cold and the regen is limited, the drive units will go into a battery heating mode during regen that will a.) provide additional heat for the battery, and b.) provide additional regenerative braking force (about 7 kW on a dual motor car).

This is done by creating inefficient wave forms in the drive inverter. This process results in additional high pitched noise from the drive units. It’s the same noise non-heat pump Model 3s make when preconditioning the battery for charging.

 

[rorrim]

What’s that sound?

When the battery is cold and the regen is limited, the drive units will go into a battery heating mode during regen that will a.) provide additional heat for the battery, and b.) provide additional regenerative braking force (about 7 kW on a dual motor car).

This is done by creating inefficient wave forms in the drive inverter. This process results in additional high pitched noise from the drive units. It’s the same noise non-heat pump Model 3s make when preconditioning the battery for charging.

Here’s what I notice (I took a short video clip which is hard to hear if you find my second posting in this thread above)...Let’s say I’m driving on the highway going 65MPH and the battery pack is still cold and regen reduced, when I let go of the accelerator pedal to slow down as I approach my exit, the car coasts and very slowly reduces speed as regen attempts to start working. As this is happening, I can hear a very high pitched and loud electrical regen sound that lasts the entire time. If I coast for 1/4 mile as I reduce speed I hear it the entire time. I can only imagine how loud it is outside the vehicle.

This is just an example of the worst case situation for this. When I had a loaner model S recently when my Modey Y was in service, the regen braking was reduced in same situation, but there was no high pitched loud electrical sound. Why the difference?

 

[Tim42069]

This is done by creating inefficient wave forms in the drive inverter. This process results in additional high pitched noise from the drive units. It’s the same noise non-heat pump Model 3s make when preconditioning the battery for charging.

I drove a Model 3 for 2 years - this is definitely a different noise. Very high pitched, very annoying.

 

[VeganDiver]

Im pretty sure they are running the front motor inefficiently to produce extra waste heat to condition the battery. Mine does the same but only when navigating to supercharger.

 

[Big Earl]

I drove a Model 3 for 2 years - this is definitely a different noise. Very high pitched, very annoying.

The Model 3 got this in a software update at some point in the past ~year. It’s hard to keep track of time these days.

 

[Big Earl]

Here’s what I notice (I took a short video clip which is hard to hear if you find my second posting in this thread above)...Let’s say I’m driving on the highway going 65MPH and the battery pack is still cold and regen reduced, when I let go of the accelerator pedal to slow down as I approach my exit, the car coasts and very slowly reduces speed as regen attempts to start working. As this is happening, I can hear a very high pitched and loud electrical regen sound that lasts the entire time. If I coast for 1/4 mile as I reduce speed I hear it the entire time. I can only imagine how loud it is outside the vehicle.

This is just an example of the worst case situation for this. When I had a loaner model S recently when my Modey Y was in service, the regen braking was reduced in same situation, but there was no high pitched loud electrical sound. Why the difference?

Yes - that’s a perfect description. When you hear the high pitched sound, the motors are operating in that inefficient mode, providing some additional heat to the battery and a few extra kW regen.

Model S & X don’t (currently) use the drive units to generate heat for the battery, so they don’t make the noise.