[throw0101d]

> Tesla really deserves some kudos for pushing the 48V architecture and the Ethernet-based communication.

For the record, 42V systems were experimented with in the 1990s:

* https://en.wikipedia.org/wiki/42-volt_electrical_system

In the 2011 German automakers agreed to 48V as the next step after 12V:

* https://en.wikipedia.org/wiki/48-volt_electrical_system

BMW was the first the first with Ethernet:

* https://www.marvell.com/blogs/the-right-stuff-a-past-and-fut...

[cyberax]

This has been a real head-scratcher for me. BMW and other automakers could have vastly improved their cars by switching to 48V a decade ago, but they still keep just plodding along with 12V.

I have no explanation for this.

[m463]

I think it's like any existing vs new tradeoff.

Tesla didn't have any existing, so their clean-slate math was clearly in favor of 100% new technology.

(Well, they did have 12v existing in their other cars, but they were clean-slate in the truck.)

[phlipski]

It's a classic chicken and egg economic problem. BMW doesn't make the chips/electronics that support the 48V architecture - Bosch & Continental (with NXP/TI/Infineon/Renesas as their silicon suppliers) do and they're not going to support 48V unless ALL (or a significant majority) of the automakers will. So it's a game of chicken.

[maxerickson]

The semiconductors have been available for 20 years.

[michaelt]

Eh, yes and no.

I designed some stuff along these lines 15 years ago. At that time, 12 volt stuff was not just available, it was available with great economies of scale and a huge range of options, off the shelf. You need an automotive-qualified relay? A light? A solenoid? A DC-DC converter module? A fan? You'd have 100 choices at 12v, 30 choices at 24v and 3 choices at 48v.

[hulitu]

> automakers could have vastly improved their cars by switching to 48V a decade ago,

The microcontroller still runs at 5/3.3/1.8 V.

[numpad0]

care to define "improve"...?

[cyberax]

More robust, cheaper (far simpler wiring harness), eventually ability to do zonal assembly.

[numpad0]

Are BMW cars less reliable, expensive, not ready for zonal assembly...?

Major car components like doors or front axles are assembled in parallel to miscellaneous parts on the main body, and all .join() at the final assembly. This had been the case for past 30-50 years, possibly more, in case this needs to be said.

[cyberax]

They can be even more reliable. And they definitely _are_ expensive.

> Major car components like doors or front axles are assembled in parallel

And doors (and tailgates) are the biggest body component that is _sometimes_ assembled independently. Then workers manually route cables through the body.

Pre-routing cables inside panels that can then just be welded together can save a lot of labor.

[numpad0]

> And doors (and tailgates) are the biggest body component that is _sometimes_ assembled independently.

Sometimes? What and when on Earth is this about? Pre-WWII?

They wash and paint and dry the whole body at once _for paint consistency_, then take off doors and trunk lids and bumpers and send them into separate assembly lines. Those major parts flow parallel "threads" in sync and converge near the end, where connectors are plugged in and those major parts are bolted back in and plastic trims are pushed in to tuck everything under. Cars were basically always done that way for a long time everywhere. I think even lots of hand made supercars are like that, only except tact times are magnitudes longer.

> Then workers manually route cables through the body.

> Pre-routing cables inside panels that can then just be welded together can save a lot of labor.

What do these even mean? Are you hallucinating workers crimping cables in-situ? They just clip on harnesses and plug in couplers in "the line". Never seen under a door trim?

It sounds like you're either extremely ill-informed, or worse yet, potentially, intentionally misinformed about car manufacturing that what you see is advanced manufacturing. I think you should... look more closely into what "legacy auto" have been doing forever.

[theshrike79]

Tradition, long supply chains etc.

Tooling all their shit to 48V is a massive undertaking with pretty much zero advantages.

[cyberax]

They don't need to retool all the factories at once. They could have gradually introduced 48V systems in parallel with 12V, slowly phasing in new components as they replaced the old 12V.

[typewithrhythm]

Converting between voltages is not a free action, and running two systems is more complicated than one...

You really need some special component that is much better at 48 for it to be worth it, otherwise a delayed platform switch is better; one some competitors have moved and the suppliers exist.

[cyberax]

Starter motor, power steering, heated seats, powerful headlights, power-hungry onboard computers.

They _all_ benefit from 48V.

[shiroiushi]

On top of all that, almost all the wiring in the car can be made thinner, because of the greatly reduced losses. This saves a bit of weight, but also a lot of cost because copper is expensive.

[numpad0]

I'm sorry but the other comment is more correct. 48V standard was originally created for mild hybrid systems for ICEs during mid-2000s as a stopgap solution to full hybrid transition. Looks like the earliest mass-production 48V-class system was a 2001 Toyota that ran at 36V.

The integrated starter generator(ISG) is usually a pancake shaped motor that replaces clutch/torque converter in ICE car, nothing like the regular starter motor.

MHV was not even real hybrid, and is no longer relevant, so was 48V, at least for a while.

[Kirby64]

The special component was supposed to be the starter. With start stop systems essentially mandatory, the starter runs much much more often and therefore wiring savings on the starter are pretty useful…

[vardump]

Less copper in the car is not a "zero advantage". Cheaper and lighter.

[iknowstuff]

none of them actually shipped a mass market almost exclusively 48V product if you’re trying to imply tesla’s push isnt as massive as it is.

[MuffinFlavored]

> BMW was the first the first with Ethernet:

BMW ENET is non-standard, DoIP is standard. :)