On, and now Off, the Tesla Bandwagon

[SWO]

Gigacastings are repairable, per Tesla's repair guide. Not everything in them, but if you get to the portion that cannot be welded, then you are completely in "totaled car due to excessive damage" area. For example, the frame rails up front are not part of the casting, and if you are pushing beyond the frame rails, you are in a very substantial accident.

Structural battery pack - Sandy Munro had a great take on this. He's a former Ford engineer, and runs a company that does teardowns of all the EVs they can get their hands on and then sells the reports on them to other companies. Sandy said that you can make something highly reliable, or highly reparable, but they are almost mutually exclusive when it comes to batteries. By leaving the pack so that things can be opened up and modules replaced, the design in and of itself is less reliable. The Model 3/Y packs have been out in the 2170 variant since late 2017, and the defect rate of these requiring replacement is lower than the Model S/X packs that preceded them. Tesla says (for them) it is more cost effective to sell the car at a lower price and if a pack fails to replace it and then send the bad pack in for recycling and not even try to repair it (outside of the penthouse - where the electronics are and are pretty accessible).

EDIT - this article has the image from Tesla's repair guide for body shops. It shows what parts of the casting can be welded and how:
https://www.repairerdrivennews.com/...-despite-many-doubts-about-their-performance/

I find the claim that it can be repaired highly dubious. High temperatures will greatly affect the properties of aluminum. It will never be the same and we're talking about part of the crash structure. Not sure a repair shop or insurance company (the insurance company has the final say) would touch it. I know one maker's CEO (Mercedes?) recently came out saying that they won't use them because it basically makes cars disposable.

As for Sandy Munroe, Elon could fill the battery module with cheez whiz and he would call it a genius idea. He's also the last person an enthusiast wants consulting their favorite brand because he would make a car entirely out of those crappy little plastic clips if he could, and make the disposable cabin air filter an integrated part of the drive motor if it would save 10 cents per vehicle.

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[theduke]

I find the claim that it can be repaired highly dubious. High temperatures will greatly affect the properties of aluminum. It will never be the same and we're talking about part of the crash structure. Not sure a repair shop or insurance company (the insurance company has the final say) would touch it. I know one maker's CEO (Mercedes?) recently came out saying that they won't use them because it basically makes cars disposable.

As for Sandy Munroe, Elon could fill the battery module with cheez whiz and he would call it a genius idea. He's also the last person an enthusiast wants consulting their favorite brand because he would make a car entirely out of those crappy little plastic clips if he could, and make the disposable cabin air filter an integrated part of the drive motor if it would save 10 cents per vehicle.

That's why the gigacast is illustrated in different colors. Not all of it is structural, some of it like extrusions are present to provide a point for fenders, etc. to attach to. Those parts can be AL welded to rebuild an attachment point, etc. Structural parts are shown as not weldable, and would total the car.


Now, if that will be adopted by body shops, who knows. This is new ground for any manufacturer (gigacastings).

 

[SpaceEVDriver]

I find the claim that it can be repaired highly dubious. High temperatures will greatly affect the properties of aluminum. It will never be the same and we're talking about part of the crash structure. Not sure a repair shop or insurance company (the insurance company has the final say) would touch it. I know one maker's CEO (Mercedes?) recently came out saying that they won't use them because it basically makes cars disposable.

Cast aluminum alloys with certain compositions can be re-welded and repaired. That's not the problem.

The problem is that with a unicast structure, some of the energy from an impact to any section is, always, transferred to other sections as well. A uni-cast structure on a vehicle cannot be certified as safe-to-use without a full analysis of the entire part, including everything that appears not to have been involved in the accident. So, sure, it's possible that a small fender-bender might not cause damage to the safety structure of the part, but it's impossible to tell without something like an X-ray CT scan of the entire part. I won't reuse carabiners in my climbing kit if I drop them for the same reason--you cannot tell if there's damage to a key piece of safety equipment unless you do a full analysis.

I wouldn't purchase a vehicle with a unicast structure if it had been involved in an accident unless the entire structure was replaced and I could verify that it had been replaced.

As for Sandy Munroe, Elon could fill the battery module with cheez whiz and he would call it a genius idea. He's also the last person an enthusiast wants consulting their favorite brand because he would make a car entirely out of those crappy little plastic clips if he could, and make the disposable cabin air filter an integrated part of the drive motor if it would save 10 cents per vehicle.

Agreed. I like the tear-down work he does, but I keep him on mute because his analyses are, at best, silly. He seems like the kind of engineer who would spend $100B on over-analyzing the engineering of every nut, bolt, and fastener of a car. Sometimes he makes good points, but it's mostly noise.

 

[D’Roc]

I find the claim that it can be repaired highly dubious. High temperatures will greatly affect the properties of aluminum. It will never be the same and we're talking about part of the crash structure. Not sure a repair shop or insurance company (the insurance company has the final say) would touch it. I know one maker's CEO (Mercedes?) recently came out saying that they won't use them because it basically makes cars disposable.

As for Sandy Munroe, Elon could fill the battery module with cheez whiz and he would call it a genius idea. He's also the last person an enthusiast wants consulting their favorite brand because he would make a car entirely out of those crappy little plastic clips if he could, and make the disposable cabin air filter an integrated part of the drive motor if it would save 10 cents per vehicle.

I love watching Munroe videos and think Sandy can bring some valuable insights but his insights, such as eliminating as many interior buttons as possible in the name of cost savings, goes against a delightful user experience that many of us expect. VW went with capacitive for cost savings but has announced bringing back buttons due to customer feedback.

 

[SWO]

Cast aluminum alloys with certain compositions can be re-welded and repaired. That's not the problem.

The problem is that with a unicast structure, some of the energy from an impact to any section is, always, transferred to other sections as well. A uni-cast structure on a vehicle cannot be certified as safe-to-use without a full analysis of the entire part, including everything that appears not to have been involved in the accident. So, sure, it's possible that a small fender-bender might not cause damage to the safety structure of the part, but it's impossible to tell without something like an X-ray CT scan of the entire part. I won't reuse carabiners in my climbing kit if I drop them for the same reason--you cannot tell if there's damage to a key piece of safety equipment unless you do a full analysis.

I wouldn't purchase a vehicle with a unicast structure if it had been involved in an accident unless the entire structure was replaced and I could verify that it had been replaced.

True....and welding the material will harden it, which leads to cracks. Point is, the whole gigacasting becomes a mess after an accident.

Spending 5min on Google....it looks like Elon's solution is for repair assemblies to be bolted to damaged sections. From a structural perspective that's probably the best way to do it, but also an ugly way to repair a vehicle.

 

[SpaceEVDriver]

True....and welding the material will harden it, which leads to cracks. Point is, the whole gigacasting becomes a mess after an accident.

Spending 5min on Google....it looks like Elon's solution is for repair assemblies to be bolted to damaged sections. From a structural perspective that's probably the best way to do it, but also an ugly way to repair a vehicle.

But even doing that doesn't certify that the "undamaged" sections are truly undamaged.

Part of the point of failure points on vehicles is, for example, that a bolt that's designed to shear in a well-understood failure mode means you can quickly certify that no more than a certain amount of energy was transferred through that bolt. It's basically a mechanical fuse. You cannot get that in a unicast.

 

[SWO]

I love watching Munroe videos and think Sandy can bring some valuable insights but his insights, such as eliminating as many interior buttons as possible in the name of cost savings, goes against a delightful user experience that many of us expect. VW went with capacitive for cost savings but has announced bringing back buttons due to customer feedback.

Yeah, his analysis is predictable. Everything that's steel should be aluminum. Everything that's aluminum shoube plastic. Screws should be replaced with clips. Clipped pieces should be integrated moldings.

His perfect car is basically disposable.

 

[SWO]

But even doing that doesn't certify that the "undamaged" sections are truly undamaged.

Part of the point of failure points on vehicles is, for example, that a bolt that's designed to shear in a well-understood failure mode means you can quickly certify that no more than a certain amount of energy was transferred through that bolt. It's basically a mechanical fuse. You cannot get that in a unicast.

Oh I agree 100%, which is why I think insurance companies and repair shops won't touch them

 

[voxel]

I've heard the same on this forum regarding the MME's ride being too harsh but that is not my experience.

The Y's ride quality is vicious/harsh but the MME's ride quality isn't great either.

I'm finding myself daily driving my Ioniq 5 more than the MME because it is quieter and suspension is far more compliant... The BMW i4 I owned before was even quieter and more comfortable too (had rear air suspension).

The MME's strength is it is good at everything without excelling at anything.

 

[SWO]

But even doing that doesn't certify that the "undamaged" sections are truly undamaged.

Part of the point of failure points on vehicles is, for example, that a bolt that's designed to shear in a well-understood failure mode means you can quickly certify that no more than a certain amount of energy was transferred through that bolt. It's basically a mechanical fuse. You cannot get that in a unicast.

Relevant to this topic.

Tesla Model Y Owner Finds Scary Cracks in Gigacast Front End

https://news.yahoo.com/tesla-model-y-owner-finds-225415222.html

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