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It requires detailed training to build/rebuild an engine from scratch as well. Making sure the clearance tolerance for the bearings, valves, and a bunch of other critical stuff are correct. Accounting for how much the piston rod expands and contracts under load.(The rod will lengthen slightly at the top of the stroke.) Bolts for the bearing caps and cylinder head must tightened in a specific pattern and in iterative amounts of torque.

Get some of this wrong and the engine self destructs. In the worst case hot internal parts of the engine exit the engine and cause a fire.

Porsche had an issue where they used some bad bolts causing catastrophic engine failure and several vehicles to burn on their GT3 line.

https://www.motorauthority.com/news/1090959_porsche-fires-ev...

Basically, there are many components on cars that require specialist skills to get right every time.

Woah, that's wild. Is a screw-up that universally catastrophic across engines? My very, very naive understanding of cars is pushing me towards thinking that a homologation version of a GT3 car is sort of an extreme outlier, but I know very little about engines, and my intuition is almost certainly way off.

How often do cars get an engine rebuild by a local mechanic these days? When the timing chain failed in my Saturn, a new engine was more than the car was worth.

That's a good point; my VW GTI got one at a local shop under insurance a few years back. The turbocharger wasn't hooked up quite right the first time. It wasn't a severe issue - the engine was just noticeably less powerful. Luckily it was a quick fix and they were very good about rectifying the issue, but yeah, what you're saying checks out, even in the outlier cases where a fix is covered.

(Humorously, in a chain of weird luck, I also had a full rebuild of a regular Golf engine in the same five year span, but that one was done at the dealer.)

I’ve got an LS6 build in process right now. Lots of us do it on the regular.

It’s not that common with shitboxes, but even then it happens. We swapped my kids Honda Civic’s head about a year ago after a blown head gasket.

I've just finished rebuilding my BP4W race engine for my mazda. It seems like an annual event for me considering the amount of power I'm pushing through the poor thing.

Rare. More common in high-performance because they're pushing the limits.

No it is not universal think of all those beater cars you see on the road they don’t need the precision as a 300+ hp car. Just keep adding oil. Also people do things like valve adjustments because they can be out by a certain factor and still run just with decreased performance. Obviously you can have certain aspects of an engine that will later prove to be fatal but there are lots of engines that run like crap and get people from A to B just fine. I am not saying some precision isn’t needed but for a lot of applications it is somewhat forgiving.

Right, and in my experience they get it wrong more often than not on ICE cars, but the result is an engine with poor fuel economy that smells, knocks, throws a rod or runs roughly, not the whole car spontaneously catching fire and melting into a puddle.

> Especially the single application seal

Mechanics replace seals all day long. Heads are a far more extreme environment than a battery case.

> all the right OE specific equipment, the right checklists

This is the situation independent shops already are in for Audi, BMW, etc. They'll continue to do so if repairs end up being needed. What I doubt is the volume will be high enough to be worth the bother. If the battery needs rebuilding, they'll send it out to a third party like they do with starter motors or clutch linings. They'll continue to do alignments, tires, coolant changes, bearing swaps, etc. It's just the total pie is going to shrink and many places will need to close.

Dude, no. With your argumentation a mechanic should never replace a fuel pump in an ICE vehicle, or rebuild an engine, or rebuild a transmission, or replace airbags. There are speciality OE tools and training required for all of those jobs and guess what - mechanics are able to get those tools and the required training. The same as they will be able to get the tools and training for EVs. Its not rocket surgery, don't think you're working on some kind of crazy tech, its a battery and a motor. Source: electronics designer for steering systems

Very specialized things are normally outsourced to other mechanics. You can easily earn a life if you specialize in fixing car switchboards, specially when you are the only company in town that does it. Tools are expensive normally and earning the skills need a lot of self-training hours. As long as the spare part is expensive, too delicate or too risky there is a niche.

> The days of mechanic shops servicing these vehicles is going to have to be over…

What do you think they do instead? Throw the entire car away after a year? Obviously they get serviced by mechanics - don’t be silly.

Send them back to the manufacturer and have them repaired.

Who do you think repairs them at the manufacturer’s servicing workshop? Mechanics. Working in a shop.

I think, based on the argument, OP means "mechanic" and "shop" in the colloquial "non dealer/manufacturer-affiliated" sense.

What if there is no dealer (Tesla)?

Usually there are officially licensed contractors that provide repair services on behalf of the manufacturer. These contractors will have all the right equipment, materials and procedures.

This monopoly is going to have to be broken; we can't have an entire economy of motor vehicles run on Apple Shop repair pricing. This is already being seen around the John Deere DRM issue.

Saying that a battery array and an electric motor is more complicated than an internal combustion engine is laughable at best. After all that’s one of the big draws of switching to EVs: A simpler and by extension) more reliable propulsion system.

A battery typically has, excluding the rest of the EV:

    - Around 10-20 microcontrollers.
    - Between 150 and 250 voltage sensors
    - Between 150 and 250 tap fuses with fuse blow sensors
    - Between 5-10 contactors with sensing contacts
    - Around 50-100 temperature sensors
    - Around 300 to 500 N-fet switches with balance resistors
    - (Depending on the design).. up to 300 bus bars with perhaps 600 bolts.
    - In some instances, you'll find up to 50 pressure sensors
    - A variety of interlocks and plug sensors

Aren't most of these just arrays of identical parts, replicated for each cell (or, repeated for groups of cells).

How fault-tolerant are the battery packs? I assume, with all these fuses and sensors, it should be able to safely handle a wide range of internal failures.

The packs typically have near zero fault tolerance. If there is a fault with a single sensor, they will complain and go into a limp mode or refuse to function altogether. (This is because without a single sensor, it might be impossible to detect if the pack is about to catch fire).

Also each sensor is usually at the same potential as the cell that it's monitoring. So if there is a sensor fault, it could mean that it's unplugged or has come loose. Can you imagine the risk of a dangling 600V thing flying around inside the box?

For that reason though ... I'd need two hands to count how many technicians have accidentally shorted two cells in packs together by plugging the wrong sensor into the wrong place and shorting i.e. cell 32 to 42. When this happens, it will blow up a bunch of random surface mount fuses in the control boards, and other things all over the place. You need a lot of attention to detail to tear these things down.

People play with ev batteries to build gokarts, I think mechanics can be trained to do it

If secondary market teslas start bursting into flames it's going to hurt Tesla's reputation even if they swear up and down that it was an unlicensed shop every time. So they'd better start sharing repair manuals.

> The days of mechanic shops servicing these vehicles is going to have to be over

Explain to me again why I want to own one of these cars?

mechanics are already repairing battery packs with very grateful customers. thank goodness