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Uhm, there is no way that a mechanic should ever try and rebuild a battery. Never. There are multiple thousands of wires inside, and multiple hundreds of tap f

Uhm, there is no way that a mechanic should ever try and rebuild a battery. Never. There are multiple thousands of wires inside, and multiple hundreds of tap fuses. Every single bolt and joint is critical and needs just the correct amount of cleanliness and jointing compound applied. The safety systems only work as well as the battery can isolate the problem (usually isolating the battery from the vehicle). Random workshops working on electric cars will just lead to internal battery problems that are uninterruptible by the control systems (ie a loose bolt or a washer floating in the casing), and this will lead to fires. And after you’ve pulled it apart, what about the quality control on all the casing water seals? Especially the single application seals (gaskets don’t work well in practice)? Battery aside, if you unbolt a motor resolver or move anything important then you need to do a resolver or phase calibration, which you can’t do without OE special equipment. Again, this could cause serious issues like hardware overcurrent and sudden cut outs, loss of power steering etc at high speed. The days of mechanic shops servicing these vehicles is going to have to be over… there is no way it will ever be safe for someone to touch the power train without all the right OE specific equipment, the right checklists and several weeks of training for each vehicle. Source: I was an EV battery design engineer.

glitchc 5y ago
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.
- aetherspawn 5y ago
  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
  - HPsquared 5y ago
    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.
    - aetherspawn 5y ago
      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.
gameswithgo 5y ago
mechanics are already repairing battery packs with very grateful customers. thank goodness
Washuu 5y ago
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-every-911-gt3-engine-will-be-replaced 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.
- MikeBVaughn 5y ago
  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.
  - analog31 5y ago
    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.
    - MikeBVaughn 5y ago
      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.)
chrisseaton 5y ago
> 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.
- aetherspawn 5y ago
  Send them back to the manufacturer and have them repaired.
  - pjc50 5y ago
    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.
  - chrisseaton 5y ago
    Who do you think repairs them at the manufacturer’s servicing workshop? Mechanics. Working in a shop.
    - MikeBVaughn 5y ago
      I think, based on the argument, OP means "mechanic" and "shop" in the colloquial "non dealer/manufacturer-affiliated" sense.
      - throwawayboise 5y ago
        What if there is no dealer (Tesla)?
        aetherspawn 5y ago
        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.
hnac12 5y ago
People play with ev batteries to build gokarts, I think mechanics can be trained to do it
coryrc 5y ago
> 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.
throwawayboise 5y ago
> 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?
ivan1783 5y ago
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
- pvaldes 5y ago
  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.
EamonnMR 5y ago
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.

glitchc 5y ago

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.

aetherspawn 5y ago
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
- HPsquared 5y ago
  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.
  - aetherspawn 5y ago
    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.

gameswithgo 5y ago

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

Washuu 5y ago

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-every-911-gt3-engine-will-be-replaced 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.

MikeBVaughn 5y ago
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.
- analog31 5y ago
  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.
  - MikeBVaughn 5y ago
    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.)

chrisseaton 5y ago

> 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.

aetherspawn 5y ago
Send them back to the manufacturer and have them repaired.
- pjc50 5y ago
  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.
- chrisseaton 5y ago
  Who do you think repairs them at the manufacturer’s servicing workshop? Mechanics. Working in a shop.
  - MikeBVaughn 5y ago
    I think, based on the argument, OP means "mechanic" and "shop" in the colloquial "non dealer/manufacturer-affiliated" sense.
    - throwawayboise 5y ago
      What if there is no dealer (Tesla)?
      - aetherspawn 5y ago
        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.

hnac12 5y ago

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

coryrc 5y ago

> 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.

throwawayboise 5y ago

> 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?

ivan1783 5y ago

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

pvaldes 5y ago
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.

EamonnMR 5y ago

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.