Fuses are not items that should be replaced normally - they are self-destroying emergency protections for the electrical system.

If it is protecting that end users can plug arbitrary loads into, that is one thing - but this doesn’t sound like that?

Why did that fuse blow? Because if that is not addressed, it’s likely to just blow again.

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bradfa an hour ago | parent | next [-]

This fuse blows because a crash was detected and it is to protect the people inside the car and rescuers. The article argument is that it can blow even for small crashes where no damage to the battery occurs but rehabilitating the vehicle still incurs an outrageous cost. This is not a simple over current protection fuse.

$1000 for the module with the fuse seems ok to me. Another $3000 to link the module to the vehicle is the outrageous part.

	▲	jinzo 12 minutes ago \| parent [-]
		They are not only linking it to the vehicle, they are doing a LOT of other checks on the battery - that it's not damaged in non-obvious ways. For that you need trained people (it's really high voltage and amperage stuff), tooling AND you really need to be sure you guarantee everything is OK. Even the basic mechanical disconnect and lowering of the battery is far from simple (and requires A LOT more expensive tools than changing a wet belt - not because they are greedy, but because a lift that can lower such hevy battery costs a lot of money, mostly in materials), and that's not even opening it, making sure you don't get electrocuted when you work on it ect.

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jacquesm an hour ago | parent | prev | next [-]

I think the people that replace fuses are aware of the potential issues around them. The article - which I'm sure you've read so don't take this as commentary on your comment - details that in other electric vehicles, for instance Tesla this is handled quite differently:

"While Tesla’s pyrofuse costs €11 and the BMS reset is around 50€, allowing the car to be safely restored, BMW’s approach borders on illogical engineering, with no benefit to safety, no benefit to anti-theft protection — the only outcome is the generation of billable labour hours and massive amounts of needless electronic/lithium waste."

It's not a choice between 'ridiculously inaccessible with the potential to create more damage than your car is worth' and 'push to reset'. There are many options in between, some of which would be a happy medium between the two that protect both safety, the environment and the customers' wallet. Which BMW's solution clearly isn't.

	▲	lazide an hour ago \| parent [-]
		1) a lot of people aren’t aware of that issue with fuses, and just keep replacing them while burning up wiring/ignoring actual problems. Or even worse manually bypass. It may be the case in this scenario (a crash), which is why they are forcing an inspection because the car might actually burn to the ground. 2) ridiculous repair procedures are the norm for BMW. The only brand I’m aware of that is somewhat common and worse is Jaguar. I get the complaint, don’t get me wrong, but it’s a bit like a Lotus or Lamborghini owner complaining about the rough ride. Like what did you expect bro?

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torginus 38 minutes ago | parent | prev | next [-]

Ladies and gentlemen - behold the perfect consumer

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kristjank an hour ago | parent | prev | next [-]

Fuses are necessary on any electrical system, and especially in a car, which is an electrical shitshow (floating ground, high-voltage and high-frequency interference), fuses blow all the time. Granted, usually on a well-maintained and new car it happens very rarely, but saying that it's a catastrophic and concerning event is dumb.

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jinzo 10 minutes ago | parent | next [-]

This is a pyrofuse, it does not blow with overcurrent as regular fuse, but blows in the same way airbags blow - when detecting a crash. We can debate if they blow too quick, but if you are designing this system - where and truly lives can be in danger, you would probably err on the side of caution too.

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lazide an hour ago | parent | prev [-]

What sort of cars do you drive?

I’ve never had a fuse blow on a car less than 20 years old, and then it was due to shorts due to damaged insulation and bad grounds due to corrosion, which are legit problems that need to be corrected.

Also, unlike breakers, fuses are generally immune to issues with HF interference and the like - they work through basic thermoelectric effects which iron out all but the most extreme issues. If you’re moving multiple amps in a situation described as ‘RF’, or ‘high frequency’ in a DC system that’s not just noise!

That’s a real problem that needs fixing!

Not fixing the underlying problem behind a blown fuse (or constantly tripping breaker) is how your car (or house or whatever) burns to the ground.

Or you have a Lucas, in which case my condolences.

	▲	kristjank 36 minutes ago \| parent [-]
		I'll grant you that, I had a lot of beaters. A typical thing was that a lock solenoid pulled too much current in cold weather and consistently blew the central locking fuse.

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taneq an hour ago | parent | prev [-]

Yep, might be there was a known issue that was addressed, at which put in a new one. But just replacing a fuse (or, simultaneously worse and better, just resetting a breaker) without further investigation is just kicking a very spicy can down the road.

I had a doozy of a trip issue on one project, a motor would occasionally (not always, no real pattern, hot/cold/etc. didn’t matter) trip the breaker, requiring a sparky to come out and open up the panel to reset it. We tried a bunch of things, megger-ing the motor, testing peak startup current on each phase with a fancy meter, checking phase-to-neutral current (Larger than you’d think! But this was normal, apparently.)

Everything was normal. In the end all we could think something was weird about the contactor. They took it out (I was off site at the time) and took it down to the substation to test it out.

With three phases connected to the contactor (and nothing connected on the other side) they energised the coil, and with an almighty bang it tripped the main incomer and took the entire sub offline.

Turns out there was a manufacturing defect in the contactor and sometimes for a millisecond, if the phase of the moon was right, it dead shorted two phases.

So there, even when you know everything, you don’t know everything.