Tesla Semi

[petit_bateau]

Supposedly that was a "claim to fame" for SpaceX->Tesla technology xfer. Using aerospace grade inconel on the main Model S contactors when they kept having early failures with more common metals.

I wonder if they still use inconel on all Tesla contactors now... Would it make sense to make semi busbars out of that material?

Surely it is inconel plating ?

(As @MP3Mike says, most likely explanation is undertorqued connection. Theoretical torques often need to be increased to cope with reality.)

 

[JRP3]

Let’s relax. Sky is falling scaremongering is for Presstitutes and TSLAQ scums. It doesn’t belong here. Almost any new product introduced - be it car or software - is going to have some initial niggles. Model S, X and 3 had it. But things settled down and all those initial problems are history now.

Questioning any failure in a Tesla product most certainly belongs here. Sticking your head in the sand benefits no one. Knowledge is power even if it's something you don't want to hear.

 

[JRP3]

It wasn't a busbar problem, it was a busbar connection problem.

https://twitter.com/x/status/1613218276607418369

Probably just an under torqued connection.

Yes I assumed a connection problem and include such as part of basic technology. Proper torque is critical but also not technically difficult to achieve in low volume production.

 

[MP3Mike]

Yes I assumed a connection problem and include such as part of basic technology. Proper torque is critical but also not technically difficult to achieve in low volume production.

But low volume production opens up a lot of possibilities for human error.

 

[mongo]

Supposedly that was a "claim to fame" for SpaceX->Tesla technology xfer. Using aerospace grade inconel on the main Model S contactors when they kept having early failures with more common metals.

I wonder if they still use inconel on all Tesla contactors now... Would it make sense to make semi busbars out of that material?

Inconel is great for high temperature applications (needed due to contact resistance and limited crossection). Other materials are better for lower temperature high current paths. Copper is 1/60 the resistance, aluminum is 1/20 (depends on temperature).

But low volume production opens up a lot of possibilities for human error.

As does a new assembly line with all new work instructions and tooling.

 

[JRP3]

Stupid humans.

 

[Buckminster]

 

[JRP3]

I think he's over estimating regen efficiency. Plus regen will still be limited by cell C rates which higher voltage does not change.

 

[mongo]

Plus regen will still be limited by cell C rates which higher voltage does not change.

Sure... but if the pack is 900kWh to achieve 500 miles of range, 1C is 1200hp equivalent... more than compression braking typically achieves. He scaled based on the car gen regen/pack size.
He also didn't seem to link regen to voltage beyond the I2R (and kV/RPM) efficency boost.

 

[JRP3]

He also didn't seem to link regen to voltage beyond the I2R (and kV/RPM) efficency boost.

Maybe I misunderstood when he mentioned pack voltage and regen.

 

[mongo]

Maybe I misunderstood when he mentioned pack voltage and regen.

Could be me also, I speed read the transcript after doing a keyword search.

 

[MP3Mike]

Could be me also, I speed read the transcript after doing a keyword search.

I don't think so. Essentially, he said a Model Y with a ~80kWh pack can regen 70kW, so a Semi with a pack 11x that size, ~900kWh, should be able to regen 770kW. (Which happens to pretty match the kW capabilities of the three Plaid motors the Semi has.)

No adjustments for pack voltage at all.

 

[JRP3]

Could be me also, I speed read the transcript after doing a keyword search.

I watched at 2x speed

 

[Buckminster]

2170 non structural packs:

https://twitter.com/x/status/1618079447068069888

 

[Dikkie Dik]

Haven’t had a chance to read it in full but lot’s of pics that make it worthy of a post.

Go Inside the New Tesla Semi: Features, Screens, Seats, and More

We visited Frito-Lay to find out what the Semi's interior looks like, and how it drives and charges.

www.motortrend.com

 

[willow_hiller]

First shot of the Semi charging port I've seen. Does appear to be the version 2 specification of the MCS standard:

https://www.reddit.com/r/teslamotors/comments/10ltamq

 

[mongo]

Only thing I can think of for them to make that change it that is was wearing down the two climb axles tires too fast having one motor per tire

Another is that one of the axles can be lifted with light enough load for more range, if you did that before, you either lost your climb axle, or lost the efficient single motor axle

They could lower the torque on the motor in that case (even if it reduced max acceleration). Or... increase load on that axle via the air suspension.
Given 6x2 ICE semis are a thing, seems strange to need to go to 3 axles...

 

[SageBrush]

seems strange to need to go to 3 axles...

And here I am hoping for 4 or 5 axles to reduce road damage

 

[mongo]

One possibility is that the front axle has a stronger lever arm on controlling against jacknife than having more discreet control over a rear axle? I am not a tractor-trailer dynamacist.

I've never quite understood the antijackknife approach as it applies to a trailer. Keeping the tractor straight seems like it would be rear wheels reacting against each other and the king pin. Front axle torque vectoring seems like it wouldn't do much compared to steering.
Even with one motor per axle, they could use braking for some vectoring, it's just not as controlled.

 

[mongo]

And here I am hoping for 4 or 5 axles to reduce road damage

Is road damage dependent on torque as well as load?