Bizarre, awesome side effect of 5.8.8?

Bizarre, awesome side effect of 5.8.8?

So I was showing off my car on Tuesday, and the balloon squeal was as obvious as it's always been (approaching 12k miles since last April, VIN 83XX). However, with the 5.8.8 update late Wednesday night, the squeal is gone, replaced instead with very quiet Jetson's-like electric car sound. while it's possible it's coincidence, if it's not then this is what's obscenesly cool about Model S. It doesn't just get better, it gets better remotely, overnight.

Could anyone else--ideally with a 60 that had the squeal--confirm that 5.8.8 did indeed fix the squeal?

Car t man | February 21, 2014

Technically, if they now know what the issue is, it might be possible to alter some parameters, to achieve this. But, it could also be a coincidence, as temperature can have an effect.

Lesser V builds are affected by temps and moisture in terms of sound, regen intensity, etc. High end builds not so much, but can be to a degree. Hard
to say. Observe and update, so we know.

Car t man | February 21, 2014

Lesser EV builds (motors and drive inverters)..

Carefree | February 21, 2014

I just had my annual service done and they forced 5.8.8 to fix an issue I had with the energy saving mode. My squeal is still there when I accelerate hard.

Mathew98 | February 21, 2014

Hmmm, if you don't stomp on the pig then it won't squeal, will it?

Like a popular Guido character used to say, "Take it easy. My hair, my hair, he touched my hair!"

J.T. | February 21, 2014

@Mathew98 Saturday Night Fever?

ir | February 21, 2014

The squeal is gone too from my S85. Service center couldn't explain how they made it go away, whether it was 5.8.8 or something they accidentally fixed when doing other service like the 12V.

Sounds like 5.8.8 could be the culprit. Maybe they tuned the inverter control firmware.

defmonk | February 21, 2014

Nope. My S60 still squeals after the update.

MacDaddyDude | February 21, 2014

Good news that the squeal is gone, and if 5.8.8 did indeed fix it, then it is also good that Tesla is hiring Apple employees. The down side would be if they ever hired from Microsoft or Oracle...the world would likely explode!

Thomas N. | February 21, 2014

That's all we need, the Blue-Car-Of-Death.

AndreyATC | February 21, 2014

With my recent 5.8.8 squeal is gone too
I can still hear it tiny bit at very max acceleration, but the sound is a lot quieter than it used to be
It's completely gone under all other conditions

The side effect in my case is different though
I'm now getting 287whm on the same commute from previous 400+
Yes, the temperatures are now in 30s vs 20s, but my car is always in heated garage (60F)

riceuguy | February 21, 2014 at least 3-4 spontaneous loss of squeal occurrences! And Andrey, my wh/m is way down as well. Hope they didn't throttle back the power to solve the problem! Conspiracy theorists...have at it! :-)

AndreyATC | February 21, 2014

Yeah, but you'd feel it only in top-end, when you floor it
For 20-40Kw driving style, it's really just better consumption than it was pre 5.8.8

ShockDoc | February 21, 2014

I implemented 5.8.8 last night and noticed immediately with my first highway merge how much quieter my drive was this morning. The squeal appears to have been muted and I arrived at work with 7 additional miles of range more than usual too! P85+ 8K miles.

Pungoteague_Dave | February 21, 2014

my car still squeals. we call him Ned...

AmpedRealtor | February 21, 2014

Not Wilbur? LOL

ran23455 | February 21, 2014

or Tessie?

hsadler | February 21, 2014

I still have the squeal.

It comes from different parts of the car - coincident with where my wife is sitting.

Only happens when I am driving.

diegoPasadena | February 21, 2014

So - I didn't think it was possible to do something about the squeal by software short of limiting acceleration - which would lead to a much louder squeal of a different kind, I'm sure!
Today, I tested it.
On the first "flooring", there was silence until about 45mph (unusual, because it used to set in immediately), but then it squealed. The note was slightly different from the usual one.
But then I tried it three more times, and there was nothing but silence!
WTH!!! How can that be?
I haven't timed the acceleration, but without clocking it, at first glance it feels pretty much the same as always, so no fear there.
But there is definitely a change, coincidental or not.

HGP16 | February 21, 2014

S60 #092xx-squeal seems to be gone after 5.8.8 update.

diegoPasadena | February 22, 2014

OK, there is definitely something up with this new upgrade! I did my regular drive today, one that for a year now has taken me back home with just about 315 Wh/mile. This is pretty much reflected in the car's lifetime average usage, because this is my most regular drive. Lifetime: 315.
Tonight, I got home with 290 Wh/mile showing. The drive was not different from every other day - at least not in a substantive way.
Is that possible? An 8% efficiency improvement with a software tweak? A friend of mine theorized that they might have fine-tuned the output frequency, and that the reduced/disappeared squeal might indicate that the output frequency now is cleaner. This, in turn, might also account for greater efficiency.
Does that sound plausible?

SamO | February 22, 2014


Nu2Ecar | February 22, 2014

A more straightforward and more likely explanation is they simply reduced the power slightly. | February 22, 2014

Seems to be gone in my S85 too, or at least gone until I am hitting max draw--will need to test a bit more tomorrow.


cfOH | February 22, 2014

My car has had 5.8.8 for a while and it still sounds the same (cool electric whine) when I stomp on the Go pedal. P85+ VIN ~16K

vincent.himpe | February 22, 2014

They may have altered the chopping frequency in the inverter.
The squeal comes from the large current running through the ferrite coils in the inverter. change the chopping frequency and you will push it out of audible range.

pretty cool that can even alter firmware deep in the bowels of the machine.

diegoPasadena | February 22, 2014

What is the chopping frequency? | February 22, 2014

OK, got a chance to drive over familiar roads today with 5.8.8 and I can attest no more whine during hard acceleration.



hsadler | February 22, 2014


'What is the chopping frequency? '

Chopping frequency is determined by how quickly you want your salad.

....sorry, couldn't resist.... back to my corner

NoVinNoMore | February 22, 2014

Just wondering - anyone else experience the efficiency gain? Did the change affect every MS? That would be really neat!

riceuguy | February 22, 2014

@NoVinNoMore, yes...significant gain in efficiency here, no obvious loss of power

@SDT, Let it go man. Let it go.

Jamon | February 23, 2014

Well I'll be...
In the beginning of this thread I thought you guys were crazy. Mid way through I believed there was a chance. Tonight I stomped the exhilarator of my S60 for the first time in a while. This is the only time in 13 months of ownership that I have floored it without hearing the whine. You've gotta love the software updates!

I couldn't tell if there was a reduction in acceleration. Does anyone who has a good sense of their original 0-60 time want to run a before & after experiment to see if it's any slower?

ssarker | February 23, 2014

Energy usage on my S60 seems quite a bit less since 5.8.8. Mid (with heat on 65F)to low (with heat off) 300's on my short trips as opposed to low 400's. Outside temperature still in the 20's.

diegoPasadena | February 23, 2014

@SDT - lowering has not yet been re-enabled. You patience shall be rewarded, no doubt, with V.6.0. I for one am happy to give them all the time they need to roll out a bug-free software version.

I still have a hard time believing that the changes we see with 5.8.8 are not really just a placebo effect, but my ears don't lie - I heard the while exactly one more time after updating (which is strange, I agree) and in four or five hard accelerations, there hasn't been a peep from the back. And the efficiency gains I saw are reported by several owners. My drive yesterday showed a little less difference from the old numbers than Friday, but I drove a little harder than usual, and it was still a couple of points below.

diegoPasadena | February 23, 2014

Corrections: "Your patience", "I heard the whine"
Why is it that mistakes only become visible after hitting "Submit"?

AoneOne | February 23, 2014

I forgive all typos unless they change the meaning of the post. I suggest everyone else do the same and stop this incessant worrying. Please don't be an 'errorist'.

jackan | February 24, 2014

The whine is gone!! Sounds like very low hum
jet engine when I floor the accelerator. Incredible.
Can someone explain in lay terms how this
is done? P85+ VIN 16xxx

AmpedRealtor | February 24, 2014

@ STD,

Please stop derailing threads to discuss your personal problems. This thread is about 5.8.8 fixing the balloon squeal. Take your nonsense elsewhere. We are all tired of reading your baloney on this subject, whining incessantly in thread after thread, etc.

I am flagging your post here as inappropriate and encourage others to do the same. You clearly don't know when to stop. Keep it up, your activities are already bordering on trolling. Make peace with yourself because you won't find it here. In fact, resistance to your one note diatribe is growing every day.

vincent.himpe | February 24, 2014

Allright. chopping frequency. Sorry if i get a bit technical here. My day to day life consitst of making motors spin ( in harddisks ).
I' a bit of a techno-geek. My main reason for buying the Tesla, apart from its looks and safety, was the maturity of the Technology. Tesla does things differently from the cookie-cutter clone-and-repeat that the other Ev makers are caught in. To put it simple, and with a bit of hyperbole : The other guys are still messing around with vacuum tubes while Tesla already uses integrated circuits.

so chopping frequency. In short: the motor used in electric vehicles needs AC : alternating current, like what comes out of the wall socket. Batteries canonly store DC : direct current. That big lump of electronics opposite the motor on the other side of the gearbox does exactly that. It 'inverts' the DC into AC (converting AC into DC is called rectifying). Actually when you brake use regeneration that lump of electronics switches from 'inverter mode' to 'rectifier mode' to dump energy back in the battery pack.

Now to do this inversion process they employ a technique called chopping. You apply power for a very short time , wait a bit , apply power agian, wait a bit, apply power again. By playing with the time you apply power and time inbetween you can 'reconstruct' a sinewave (AC current)

For example (us means microsecond or millionth of a second)
1us on , 9 us off,
2us on , 8 us off
5us on, 5 us off
8us on , 2us off
9us on, 1us off

and then you go back down. ( there is polarity reversal in there as well but that will get too technical very quickly. Look up PWM on wikipedia if you want to know more.

This pattern is stored in a table. Depending on how hard you press the 'go-who pedal' this table is played faster or slower. This is done by multiplying or dividing the numbers in the table.

This 'chopped' current is not really a nice sinewave yet. To smooth this out it is sent through an inductor. The motor itself is a big inductor. But additional inductors may be needed for the smoothing process.

The side effect is that this chopping turns on and off the magnetic field. so all the molecules in the core of the inductor ( and the motor) are beeing yanked left and right. pretty much like a speaker.

If you drive it normal you don't hear the squeal. It is always there just barely audible. Floor the 'Go pedal' and that effect becomes louder as you are dumping massive amounts of current into the motor so the 'vibration' becomes louder. Just like a speaker. This vibration does no harm. it is a side-effect.

Now, by playing with the shape of the sinewave( playing with the numbers in that table) you can push it out of audible range. The signal is no longer a perfect sinewave but a bit distorted. This has no impact on the performance of the motor ( actually there are signals that have better performance and create less 'loss' in the motor, thus longer battery life )

It looks to me as Tesla has tuned the frequency at which they perform the chopping to push the audible noise into the region where humans no longer hear it, or they changed the shape.

I don't know and this is speculation on my part now : since people are reporting a bit more range and the squeal is gone i suspect they changed the waveform. in essence they changed the table used to make the AC signal.

If you want to know more let me know. i can go into more detail.

Mathew98 | February 24, 2014

@vincent - Excellent explanation to the layman.

Can you explain with a little more details? ;o

vincent.himpe | February 24, 2014

about how an inverter works or the technology in the Tesla ?

vincent.himpe | February 24, 2014

Here is a simple video that shows the principle of the induction motor used:

It shows how the sinewave makes it spin. The inverter creates this sinewave by chopping the DC current from the battery. go faster means changing the frequency. It's that simple.

Tesla is the only car afaik that uses an induction motor. All the other EV's use permanent magnet brushless DC motors. ( BLDC motors ) which is actually a misnomer as the motor contains a circuit board taking the DC and making AC on-board the motor. In the Tesla that circuitry sits opposite the motor.

The key difference is this : In a permante magnet motor the total power that can be delivered is determined by the strength of that permanent magnet. Need a stronge rmagnet means you need a physically bigger one. And there are limits. (bigger means heavier means slower to accelerate as there is more mass to be moved…)

The induction motor does not have this problem. The magnet is created by the induced current in the rotor. Meaning : the more current you send into the static winding (see that video) the stronger that magnet becomes , the more horsepower the motor can deliver.
The only thing you need to care about is not melting the wires… Since the Tesla motor is liquid cooled you can pump a lot of current into that motor. as long as they can keep it's temperature in an acceptable range.

To give you an idea: Your home gets a 100 Ampere or 150 Ampere circuit at 240 volts. You never use all that power(it would pop the main breaker)

The Tesla motor gets up to almost 300 volts at up to 1200 ampere … Look at your gauge in the center. it is marked in Kilowatts. When you floor it they are sending 320 to 330 Kilowatt into that motor. Watts = amps x volts. 300 volts x 1200 ampere = 360 kilowatt which is the top of the scale.

When you are regenerating ( like rolling downhill ) you can send up to 60 kilowatt back into the battery. Try that with a gasoline car…. it would be like getting fuel back :)

ir | February 24, 2014

@vincent: Awesome explanation. Here's a specific question instead of a general "tell me more"….

"( actually there are signals that have better performance and create less 'loss' in the motor, thus longer battery life )"

Common sense would say that a cleaner sine-wave = better performance. But you mentioned that there are better shaped curves, care to elaborate?

Bighorn | February 24, 2014

This is very interesting and appreciated. I guess if I had thought about it, I would have guessed that the inverter took DC power and converted it to 60 Hz, just based on US AC standards. It sounds like the frequency is variable and correlates with the amount of power requested. Haven't watched the video, so forgive me if I'm asking something already addressed, but if you look at your derived AC current on an oscilloscope, I suspect it is stepped depending on the magnification. Is this stepping smoothed out completely or are there varying degrees of "noise" dependent on frequency? Does the cleanness of the trace have any implications for battery performance or longevity?

jackan | February 24, 2014

@vincent. Thanks so much. So theoretically,
the sound of the motor can be manipulated in
future updates?

hsadler | February 24, 2014

'So theoretically, the sound of the motor can be manipulated in
future updates?'

I'm sure - and maybe to play your favorite tune.

Seriously, a very well explained definition of the 'chopping effect'

Although I never experienced the 'squeal', I too have noticed a change in efficiency. My question is - would that change effect a decrease in performance?

NKYTA | February 24, 2014

Great explanation @vincent...I think I grokked most of it.

Bighorn | February 24, 2014

I guess on further thinking, I don't see why the battery would be influenced by the "cleanness" of the sin wave, but perhaps the motor is happier. It seems clear that whatever was done has improved efficiency, so this tuning must have a measurable impact on the motor's ability to utilize the energy.

Longhorn92 | February 24, 2014

I stomped on it after the 5.8.8 update, and unfortunately, I still get the balloon squeal noise. Software-limited 60 kWh.

Brian H | February 24, 2014

If the frequency has been bumped to ultrasonic levels and that improved efficiency, obviously the lower freq was lossy, or at least lossier. If I was a TM engineer I would be very happy that this issue had been pushed to come up with this free efficiency boost. I wonder if there is a cost, an unintended consequence like stress on some other component, etc.

Anyhow, chopping frequency in the inverter drives efficiency in the MS. Who knew?

AmpedRealtor | February 24, 2014

Balloon squeal is totally normal, per Tesla.