Amazing - Inginineerix Model 3 teardown

KarenRei

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#1
I complied the following information from Ingineerix's posts on Reddit and Youtube:

https://www.youtube.com/playlist?list=PLwPiVR1Wtwc1cxO0vlvx5rDnHShUuHvXS


Model 3 LR:

Wiring:
"Mostly CAN with a touch of Ethernet (including BroadR-Reach single pair)."

Wiring reduced by having 3 body controllers instead of 1

*No fuses* in Model 3. All solid state virtual fuses. You don't actualy blow anything, you just trigger a software shutoff of the power until you reset the "fuse".


Display:
"Connected by a 2 twisted pair system called FPD link III. There is a 4-pin Fakra HSD connector on the ICE (computer) module behind the glovebox area that can be easily accessed"


Suspension:
Top suspension arm FRP, curiously enough.
Massive front stabilizer


MCU/ECU (computers, incl. autopilot):
Liquid cooled by the main glycol loop


Seat heaters:
"Rear seats do indeed have heaters and they are connected. Just no way in the GUI as yet to enable them."


Drive unit:
"The drive unit contains the Inverter, Switched-Reluctance motor, a gear-reduction, and a differential to split the torque between the 2 wheels."

"The RWD has a higher capacity inverter than the AWD. (800A vs 500A) I don't know if there will be a "P" version yet, but maybe that one would retain the 800A in the rear and add a 500A in front."


Front motor:

There's a giant hollow already just waiting for it. "Cavernous space. You could put a small child in here." Note for if you need a smuggling compartment... ;)


Pack:
" I can tell you the voltage ranges haven't changed too much. BMS considers 100% SoC at 4.2v per cell but the bottom changed slightly; it's now 2.85v/cell for 0% SoC, whereas on S/X it was 2.5v/cell. Note that Tesla advises owners not to charge above 90% daily unless really needed, so that puts the top at around 4.1v/cell. There is also a bottom reserve of 3.5kWh that you can't touch."

4426 2170s, 96S46P arrangement, 4x modules

76kWh actual, 74kWh nominal. Possibly only 72.5 kWh usable due to the 3.5kWh "bottom reserve".

Max regen charge 192A, max discharge 1200A (ed: max discharge equates to 294-482kW / 392-646 max theoretical HP from the pack)
Min bus voltage 245V, max bus voltage 402V
Max regen 46,9kW, max discharge 370kW


Cooling:
Mounted on sizeable rubber gaskets and with a lot of acoustic foam, to keep it quiet.

Weights added to the cooling fan to ensure that it's properly balanced.


12V battery:
45 Ah. Not sealed.


Heat exchanger:
"It's a plate stack type on top of the drive unit. Looks similar to the one I showed in the 1st video where the glycol is chilled by the A/C refrigerant. "

"Yes, and not only that, but if it is super cold and they actually need to add heat (the motor/inverter is super efficient, so not much waste available), they purposely run the inverter in an inefficient mode to generate excessive waste heat to heat the pack. S/X had a ****** electric battery heater in the glycol loop and these seem to be very unreliable. So on 3 they basically did it with software!"


Build quality and engineering:
"I've taken apart hundreds of cars so far, and I find the 3 to be well put together and a lot of thoughtful engineering throughout. Particularly impressed by the high levels of integration as compared to S/X. Also going to a electric pump and filter on the DU means they want it to last a long time. Really, the only maintenance most owners will need to perform is adding windshield washer fluid and replacing tires. Maybe a 12v battery every 5 years. Brake pads should do 100k unless you do a lot of aggressive stops."

"I think you must be referring to Sandy Munro. He had a lot to say about the fit/finish and went on and on about how the first responders can't get to the cut loop. First off, none of the fit/finish issues exist on recent the cars I've investigated, and secondly, Sandy's focus on the cut loop is silly. In any accident that would need first responders to cut into the car, the HV system has already been totally disabled by the RCM (Airbag Computer). Anything that matters seems to be really good. I welcome more objective analysis though!"


General safety:
"The RCM (Airbag ECU) blows the HV pyrotechnic disconnect in the HV pack as soon as there is an accident. Easy to safe the HV system by unplugging one low-voltage connector."

"The HV system is totally isolated from the chassis, and if the BMS detects that the isolation has been compromised, (due to a short from chassis to any part of the HV system) it will open the contactors."

"The fire vents relieve any pressure inside the hermetic pack enclosure, and if there are any hot gases, the deflectors redirect them to a safe place. There is a cabin filter, but it's inside, so a post filter, not a pre-filter like the S/X have."

"There is a lot of redundancy in critical systems. I've seen it in the BMS, Brakes, Power steering Rack, CAN buses, and Power distribution (no fuses). I haven't had the drive unit apart yet, but I expect it to have some redundancy, or at least built with fault tolerance in mind."

Power steering = 2 separate controllers; one can fail and you still have power steering.

Crash energy absorption structure is unboltable. If the car is in a crash, you can remove it and install a new one.

Automatic water vent if the pack somehow gets flooded.


From another user, about Ingineerix who took the car apart, in comparison to a person who posted a different teardown:
"I don't know what qualified that person to assess the quality of engineering, but I know Ingineerix personally and have never met anyone with a higher level of engineering skill and knowledge."
 
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KarenRei

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#2
The only disappointment is that the pack is a bit smaller than claimed by the EPA. Otherwise... amazing!

Also, unfortunately we won't be seeing a pack teardown anytime soon, at least not on this car, as it's likely to ruin the pack. But he does plan to dig into the drive unit :)
 

garsh

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#3
"The drive unit contains the Inverter, Switched-Reluctance motor, a gear-reduction, and a differential to split the torque between the 2 wheels."
Is it a simple open differential? If it is, then I guess traction control uses the brakes.
"The RWD has a higher capacity inverter than the AWD. (800A vs 500A) I don't know if there will be a "P" version yet, but maybe that one would retain the 800A in the rear and add a 500A in front."
How does he know what the AWD will have???
 

KarenRei

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#5
Is it a simple open differential? If it is, then I guess traction control uses the brakes.
How does he know what the AWD will have???
Specs reported in "factory mode", I presume.

You can ask him about the differential over on reddit.

BTW, nobody's commented about the interesting part yet: switched reluctance motor. He wrote a couple posts about this. If he's right about this (I asked him for more information), then this is AFAIK the first switched reluctance motor in the auto industry. Tesla's engineers have talked before about working on it, but I didn't know that they had already gotten there! But that would contradict the claims of it being a PM motor

Ed: found the interview, from last summer

https://chargedevs.com/features/tes...ential-of-next-generation-motor-technologies/

Re-reading it, he's sort of playing coy in response to the question:

Charged: There is a lot of talk about switched reluctance machines (SRMs) as a possible next-generation EV traction motor. Do you have any thoughts on SRMs?
KL: An SRM is a very particular machine. It’s very simple to manufacture, but it’s difficult to control. It’s got some acoustic noise and vibration challenges. With design you can make it a lot better, and you can control it in a way that you mitigate all these problems.
It is not too bad in torque density, but the constant power is a bit of a challenge to build up, and you need constant power in traction applications. So, again, I’m always hoping to see new ideas and definitely it’s attractive to have something that is so robust because it’s a very simple rotor construction. It could potentially work for this class of problems.

SRMs are cheap, relatively torque dense, rugged, and very efficient in all operating conditions, without needing rare earths. They can hold a position without extra power input, but can also free wheel. There's no risk of shorting between phases if the insulation wears. Losses are in the stator and thus easy to cool. There's no back EMF like PM motors. Switching is slow (8x per rotation), which means low inverter losses. Etc. But they've been hard to make use of as traction motors for cars because of torque ripple. Easy to build, hard to control. If Tesla has mastered SRMs, that's a big deal.
 
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3V Pilot

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#8
I really like what he said about the whole Sandy Munro video. It's exactly how I felt and he seems to apply common sense instead of looking for non-issues to complain about like Munro. The more I hear about the way this car was designed and built the more I'm excited about getting one.
 

KarenRei

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#10
I really like what he said about the whole Sandy Munro video. It's exactly how I felt and he seems to apply common sense instead of looking for non-issues to complain about like Munro. The more I hear about the way this car was designed and built the more I'm excited about getting one.
Munro and Associates tore down that Model 3 on contract for an undisclosed, "not Tesla" client. So, take from that what you will.

I'm not normally one to cast aspersions about peoples' motives, and often caution others about crediting malice to cases that can just be differences of opinion. But you don't get much more of a conflict of interest than that.
 

garsh

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Munro and Associates tore down that Model 3 on contract for an undisclosed, "not Tesla" client. So, take from that what you will.
Full disclosure: Ingineer is a long-time EV-evangelist, and self-proclaimed "Tesla expert" who sells EVSE accessories. I'm not implying anything - it's just good to know about peoples' motives. I think he did a great job explaining this Model 3 teardown.
 

3V Pilot

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Munro and Associates tore down that Model 3 on contract for an undisclosed, "not Tesla" client. So, take from that what you will.

I'm not normally one to cast aspersions about peoples' motives, and often caution others about crediting malice to cases that can just be differences of opinion. But you don't get much more of a conflict of interest than that.
Not only was that tear down motivated by other auto manufactures it was also painful to see him misrepresenting things that most people don't understand and playing the "expert" on the subject while making up silly nonsense. It's bad enough to have all the wrong info out there from YouTube to reviewers who just don't know what they are talking about but when I see someone who should know what he is talking about make things up, that's even worse. I still see lots of comments and videos that still give out bad info. It amazes me how little most people know and how much they guess. I've been to the Scottsdale showroom twice and both times heard people (and sales reps) giving out wrong information. Last time I was there the sales rep told a customer the 200K tax credit limit applied to each model, not to the total cars a manufacturer sells. Maybe I'm just too anal about wanting to the know the correct info but it bugs me when wrong facts are given out or made up.
 

KarenRei

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#13
Full disclosure: Ingineer is a long-time EV-evangelist, and self-proclaimed "Tesla expert" who sells EVSE accessories. I'm not implying anything - it's just good to know about peoples' motives. I think he did a great job explaining this Model 3 teardown.
So long as he's not being paid for by Tesla or a Tesla competitor. I'll of course take any evangelism towards his own products with a grain of salt ;)
 

JWardell

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#14
Thank you @KarenRei for compiling all the useful information from Reddit. I was trying to follow it this week but there are so many little things buried it gets difficult. I'm sure there's even more useful waiting to be gleaned from the videos as more folks see them.
 

mdfraz

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Not only was that tear down motivated by other auto manufactures it was also painful to see him misrepresenting things that most people don't understand and playing the "expert" on the subject while making up silly nonsense. It's bad enough to have all the wrong info out there from YouTube to reviewers who just don't know what they are talking about but when I see someone who should know what he is talking about make things up, that's even worse. I still see lots of comments and videos that still give out bad info. It amazes me how little most people know and how much they guess. I've been to the Scottsdale showroom twice and both times heard people (and sales reps) giving out wrong information. Last time I was there the sales rep told a customer the 200K tax credit limit applied to each model, not to the total cars a manufacturer sells. Maybe I'm just too anal about wanting to the know the correct info but it bugs me when wrong facts are given out or made up.
No, you're right to be annoyed. This goes for everything, not just Tesla cars, but when someone claims or purports to be an expert on a topic and gives incorrect information, either intentionally or inadvertently, it is damaging and dangerous.

If Joe Schmo walks into a Tesla showroom and tells his buddy "I've read that Model 3s can fly", that's one thing. If a Tesla sales rep says the same thing, it's a problem. Clearly I'm exaggerating to make the point, and I'm sure it's very difficult to educate every single sales rep in every single showroom, but it's MUCH preferable for a sales rep to say "I'm not sure on that, but I will do research and get back to you" rather than to disseminate inaccurate information to potential customers.
 

3V Pilot

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#17
So, I'm confused about one detail above (but it's not hard to confuse me...lol). He says the battery pack has "4426 2170s" and all other info I've seen the number is 4416. Here is the detailed article from Electrek: https://electrek.co/2017/08/24/tesla-model-3-exclusive-battery-pack-architecture/

Not that a difference of 10 cells means anything. I'm just wondering why the discrepancy and who has the more accurate data.
 

Bokonon

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#19
Quasi-informed (but mostly fun) speculation time!

I hopped over to the carspecs.us 0-to-60 calculator and entered 370 kW, 4045 lbs*, AWD and dual-clutch transmission**.

* 4045 lbs = 3814 RWD curb weight + 80% of the weight difference between a Model S85 and P85D
** To minimize transmission/shifting losses

It came back with a 0-to-60 of 3.6s, which sounds about right for a non-Ludicrous Performance trim.

For Ludicrous Performance (i.e. sub 3.0s), you'd need at least 480 kW according to this calculator and set of assumptions. That's right at the pack's theoretical maximum discharge rate, which doesn't seem likely in a real-world application. (This isn't too surprising given that this calculator significantly underestimates the performance of the P85D, P90D, and P100D.)

For non-Performance AWD, I entered 295 kW***, 3956 lbs (3814 + 80% of the weight difference between Model S85 and S85D), AWD and dual-clutch. Result: 4.25s.

*** 295 kW = 236 kW (number I had to enter**** to get 5.1s with RWD, 3814 lbs, and DCT) * 125% (= 2 * 500A inverter / 800A inverter)
**** Yes, I am completely ignoring the 202 kW (271 HP) listed in Tesla's EPA filings.

Again, don't mistake this post as an exercise in scientific rigor just because it contains numbers. :)