Model S Technical / Mechanical Issues

[JRP3]

The pitch change to the "wheeze" sound is something I've not heard in an electric motor. Usually it's just a steady rising whine. That does sound like a resonance issue, though it may simply be inherent to the design of that motor, which because of it's high performance nature may be more subject to something like that.

 

[bareyb]

The pitch change to the "wheeze" sound is something I've not heard in an electric motor. Usually it's just a steady rising whine. That does sound like a resonance issue, though it may simply be inherent to the design of that motor, which because of it's high performance nature may be more subject to something like that.

Exactly. It does nobody any good to bury our heads in the sand. Tesla needs to be aware of this problem and hopefully they can improve the manufacturing process and increase the number of cars that don't have the problem. I called Tesla HQ today and sent them links to this thread and a copy of the Youtube video showing the sound. It was my distinct impression that they are NOT aware of the ballon squeal problem. Just the normal "whine". So I think it's definitely worth mentioning to the service center if you have the "squeal". There *may* be something they can do about it.

 

[yobigd20]

Exactly. It does nobody any good to bury our heads in the sand. Tesla needs to be aware of this problem and hopefully they can improve the manufacturing process and increase the number of cars that don't have the problem. I called Tesla HQ today and sent them links to this thread and a copy of the Youtube video showing the sound. It was my distinct impression that they are NOT aware of the ballon squeal problem. Just the normal "whine". So I think it's definitely worth mentioning to the service center if you have the "squeal". There *may* be something they can do about it.

Tesla has known about this for at least a year.

Watch starting at 4:08. This was a test drive with a Tesla employee(video uploaded July 15th 2012...so they've known about this for over a year).

Excerpt from Tesla employee:
"that is a connector that has a lot of current going through it. And there's just enough electricity in it that its where it vibrates just at the right frequency where it's audible.. We're actually thinking about changing the frequency of the electricity that goes through there so its not audible...we're aware of that noise ...its just the connector...like a little whistle. We actually call it the "deflating balloon sound."

 

[JRP3]

Not sure I buy the "current passing through a connector" explanation.

 

[bareyb]

Tesla has known about this for at least a year.

Watch starting at 4:08. This was a test drive with a Tesla employee(video uploaded July 15th 2012...so they've known about this for over a year).

Excerpt from Tesla employee:
"that is a connector that has a lot of current going through it. And there's just enough electricity in it that its where it vibrates just at the right frequency where it's audible.. We're actually thinking about changing the frequency of the electricity that goes through there so its not audible...we're aware of that noise ...its just the connector...like a little whistle. We actually call it the "deflating balloon sound."

I will say the noise in that video is not as objectionable to me as the sound in the original video of yours that I posted at the top of the thread. At least it climbs steadily as you'd expect from a motor, and doesn't rise and then taper off like a popcorn fart. It's obviously happening to varying degrees from either really pronounced (like your car) to not audible at all (like Texex's car). If they really can change the frequency and eliminate it as the employee said, then that would be great. Either way, it's a good thing that Tesla is aware of it and is (hopefully) working on a fix.

 

[mep]

Ok an update on my "noises".
Little whistle: I have a very low level whistle at exactly 9 mph. It is almost not audible. I had a loaner P85 for a couple of days and it had it too. I don't mind because it very very low.
Louder whistle: I noticed that in the loaner when hitting it and it was as clear as in the above video. My S85 does not do it and I do not remember having heard it in the P85s I test drove before.
The "humming" noise at around 75mph I had: This was very annoying and not like a whistle at all. They too took a recording and send it to some Tesla engineers, just as reported by others here on the forum. That prompted them to replace the DU and I am happy to report that now I do not have that sound any more. So that is not normal and can be fixed. Will the fix last? Who knows. I pushed the car a bit tonight and went up to 95mph. I am hearing some engine noise but it is acceptable. The humming noise is gone. I am very happy now.
A new one: A week ago I started noticing some clicking sounds from right where the seat belt comes out of the B pillar, not very loud but right next to my left ear and constantly going. The curse of a quiet car. The loaner had it too. They took care of it and that noise is also completely gone.
Overall I am very happy with their service. They took everything serious and fixed it all and I got to drive a P85 for two days. Still, I am glad I have my car back. I believe I noticed that my 19" standard tires are less noisy than the 21" performance tires.
Now my car is perfect! I like quiet!

 

[nlc]

Excerpt from Tesla employee:
"that is a connector that has a lot of current going through it. And there's just enough electricity in it that its where it vibrates just at the right frequency where it's audible.. We're actually thinking about changing the frequency of the electricity that goes through there so its not audible...we're aware of that noise ...its just the connector...like a little whistle. We actually call it the "deflating balloon sound."

Not really convinced by the explanation...
On the perf version for example, max power is 310kW, thus approx 850A DC current in the inverter input conductors, and a little less of AC current in each motor phase output conductors.
I am pretty sure there is no connector to interconnect input power conductors to inverter and inverter output conductors to motor. I think it's rather direct screwed connection.

Concerning "changing the frequency of the electricity that goes through there so its not audible" :
An inverter converts DC voltage/current from 2 power conductor to 3 AC current for the 3 phases motor. To do this, the inverter uses pulse width modulation (PWM), which can be called the carrier. The duty cycle of this pulse width modulation signal is modulated to build the AC current in the motor phase.

Thus in an inverter we have 2 distinct frequencies :

- The frequency of the PWM signal (the carrier). This frequency is fixed and is the same regardless of the motor speed. If this frequency is too low, it will be audible as a continuous whistle regardless the motor speed. Habitually, this frequency is above 15 or 20kHz, to be in the ultrasound spectrum frequency and is inaudible.

- The modulated AC current frequency in the 3 motor phases (120° out of phase between motor phases). This frequency corresponds to the magnetic rotating field applied to the stator of the motor, and thus is totally dependent of the motor speed.

Thus if the audible noise frequency that some owner hear is changing according to speed, it's because that noise comes from the 3 phases AC current, and thus this frequency cannot be changed because it is totally dependent of motor speed.

 

[bareyb]

Not really convinced by the explanation...
On the perf version for example, max power is 310kW, thus approx 850A DC current in the inverter input conductors, and a little less of AC current in each motor phase output conductors.
I am pretty sure there is no connector to interconnect input power conductors to inverter and inverter output conductors to motor. I think it's rather direct screwed connection.

Concerning "changing the frequency of the electricity that goes through there so its not audible" :
An inverter converts DC voltage/current from 2 power conductor to 3 AC current for the 3 phases motor. To do this, the inverter uses pulse width modulation (PWM), which can be called the carrier. The duty cycle of this pulse width modulation signal is modulated to build the AC current in the motor phase.

Thus in an inverter we have 2 distinct frequencies :

- The frequency of the PWM signal (the carrier). This frequency is fixed and is the same regardless of the motor speed. If this frequency is too low, it will be audible as a continuous whistle regardless the motor speed. Habitually, this frequency is above 15 or 20kHz, to be in the ultrasound spectrum frequency and is inaudible.

- The modulated AC current frequency in the 3 motor phases (120° out of phase between motor phases). This frequency corresponds to the magnetic rotating field applied to the stator of the motor, and thus is totally dependent of the motor speed.

Thus if the audible noise frequency that some owner hear is changing according to speed, it's because that noise comes from the 3 phases AC current, and thus this frequency cannot be changed because it is totally dependent of motor speed.

What do you think of the "resonance in the coil" explanation or that something else in the motor is vibrating or moving around?

 

[nlc]

Yes it's totally plausible, it can be conductors from inverter to motor, motor windings themselves, in fact any wire where the AC current flows. But the AC current frequency cannot be changed to have it inaudible because this frequency depends of the motor speed.

 

[JRP3]

I wonder if the use of the word "connector" was a misunderstanding of the word "conductor".

 

[nlc]

Maybe.
Anyway, when I will have my model S, if the "balloon squeeze" noise during hard acceleration is here, it will not be a problem for me. It's a pleasant sound to my ears, symbol of high amperage in the motor and high torque delivered to the wheels. But it will be annoying if this noise is always here, even at stabilized speed or low acceleration. Also, the "hum" noise at certain speed will be annoying because this noise seems not normal to me.

 

[mknox]

One thing I did find distressing is how hot the HPWC handle got. I charged at 80 amps for about 2 hours, and when I came out I actually burned my hand a bit on the chrome part of the handle where the button is. I almost couldn't press the release button it was so hot. I pulled it out by holding on to the plastic part which itself was almost unbearably hot. As I wound up the cable, the entire length of the cable was very warm -- I'd call it hot too. I put my hand on the car's charge port and surrounding areas and it wasn't hot at all.

Is it normal for HPWCs to get this hot? I'm wondering if most people don't notice since the car may have finished charging and the connector may have cooled down by the time they come out and disconnect.

Bump.

I still remain concerned about how extremely HOT the HPWC handle got and am interested in HPWC owners' experiences charging at 80 amps.

 

[Eggplant]

Ok an update on my "noises".

The "humming" noise at around 75mph I had: This was very annoying and not like a whistle at all. They too took a recording and send it to some Tesla engineers, just as reported by others here on the forum. That prompted them to replace the DU and I am happy to report that now I do not have that sound any more. So that is not normal and can be fixed. Will the fix last? Who knows. I pushed the car a bit tonight and went up to 95mph. I am hearing some engine noise but it is acceptable. The humming noise is gone. I am very happy now.
A new one: A week ago I started noticing some clicking sounds from right where the seat belt comes out of the B pillar, not very loud but right next to my left ear and constantly going. The curse of a quiet car. The loaner had it too. They took care of it and that noise is also completely gone.
Overall I am very happy with their service. They took everything serious and fixed it all and I got to drive a P85 for two days. Still, I am glad I have my car back. I believe I noticed that my 19" standard tires are less noisy than the 21" performance tires.
Now my car is perfect! I like quiet!

So, I have a hum that I hear around 70mph, but I sort of wrote it off as road/tire noise. It's not extremely loud, but probably the loudest noise I can hear. How can I differentiate between road noise and this noise? Do you happen to have a recording of the noise that was fixed to compare?

 

[nlc]

So, I have a hum that I hear around 70mph, but I sort of wrote it off as road/tire noise. It's not extremely loud, but probably the loudest noise I can hear. How can I differentiate between road noise and this noise? Do you happen to have a recording of the noise that was fixed to compare?

Probably passing in Neutral, to have no current flow in the motor. If the noise is still present, thus it is a vibration resonance from road/tire, or transmission, or from the rotor which can be a little unbalanced.

 

[cinergi]

Bump.

I still remain concerned about how extremely HOT the HPWC handle got and am interested in HPWC owners' experiences charging at 80 amps.

It's not supposed to get that hot. Others have had the same issue, replaced their connector, and it returned to normal "warm" temperatures. Mine doesn't get anywhere near hot even after 3 hours of charging at 72 amps.

 

[AmpedRealtor]

My HPWC connector gets very warm, as does the black cable. I wouldn't say it's hot, because I can enclose my hand around the connector and hold it for an extended period of time without burning myself. But it is not a very comfortable experience. By comparison, the door handles get much, much hotter in the sun.

FYI Tesla says this level of heat is normal when dialed in to 80A. I get 240v @ 80A = 19,200 watts. That's enough to make anything warm.

 

[mknox]

Thanks for the HPWC heat comments. This particular HPWC was at the Toronto Store. I think I'll mention it to them next time I stop by.

 

[nlc]

On a metallic part which is a very good thermal conductor, it's easy to be burned from 60/70°c. But for conductor or electronic it's not so high. I think it's not an issue. And I believe that if the temperature was hotter than normal the HPWC would cut the power, they necessarily put a temperature sensor inside IMO, because it can be very dangerous and create fire if there is a bad contact @ 80A !!

 

[Dave EV]

On a metallic part which is a very good thermal conductor, it's easy to be burned from 60/70°c. But for conductor or electronic it's not so high. I think it's not an issue. And I believe that if the temperature was hotter than normal the HPWC would cut the power, they necessarily put a temperature sensor inside IMO, because it can be very dangerous and create fire if there is a bad contact @ 80A !!

If the handle is getting too hot to touch or hold for 30 seconds, it's getting too hot. It's an issue. Period. The contacts themselves should not be seeing any significant rise at 80A - after all, they have to be able to endure 200-300A during supercharging!

There is no thermister in the handle of Tesla MS plugs, but IMO given how many issues there seem to be with bad plugs/connectors (Tesla is not alone here, see the Blink/Rema issues charging at 30A), there should be.

 

[nlc]

I misunderstood I thought that was the case of the HPWC that becames hot, not the plug. So I re-read carefully and it's curious that the charge port and surrounding areas wasn't hot. It would become hot too if it was contact problem !? Maybe it's a connection problem in the plug between wire and contacts ?

- - - Updated - - -

I get 240v @ 80A = 19,200 watts. That's enough to make anything warm.

19200W is the global power entering in the car. Fortunately it's not the power dissipated in the connector !!
80A is a lot of current, if the contact for example have 10 milli Ohm resistance, the dissipated heat power will be 0.005 x 80 x 80 = 64W !

supercharging needs very big conductor and very very good contact for sure !! We have no supercharger in France for now, what is (approx) the diameter of the supercharger cable ?