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Standardizing Automotive Connectivity

tesla.com

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Re: Standardizing Automotive Connectivity

#101

Post by cyberax »

theshrike79 wrote: post #92
cyberax wrote: post #90

Earlier quoted context omitted.

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.

Tradition, long supply chains etc. Tooling all their shit to 48V is a massive undertaking with pretty much zero advantages.

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.

Re: Standardizing Automotive Connectivity

#102

Post by cyberax »

numpad0 wrote: post #98
cyberax wrote: post #90

Earlier quoted context omitted.

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.

care to define "improve"...?

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

Re: Standardizing Automotive Connectivity

#104

Post by typewithrhythm »

cyberax wrote: post #101
theshrike79 wrote: post #92

Earlier quoted context omitted.

Tradition, long supply chains etc. Tooling all their shit to 48V is a massive undertaking with pretty much zero advantages.

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.

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.

Re: Standardizing Automotive Connectivity

#105

Post by numpad0 »

cyberax wrote: post #102
numpad0 wrote: post #98

Earlier quoted context omitted.

care to define "improve"...?

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

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.

Re: Standardizing Automotive Connectivity

#106

Post by JoshTriplett »

outworlder wrote: post #22
cyberax wrote: post #18

Tesla really deserves some kudos for pushing the 48V architecture and the Ethernet-based communication. It drastically simplifies the wiring mess that is in a typical car. And it's not even close. Just watch the teardown of Cybertruck and compare its wiring to something like F150.

We can simplify the wire mess today by using more CAN bus devices. What is ethernet bringing to the picture?

CAN has desirable electrical properties (e.g. hardware-level prioritization) if you have life-critical devices and non-life-critical devices on the same network. But it's painful to deal with from a software point of view, compared to IP-based protocols, for anything that doesn't require the properties of CAN.

Re: Standardizing Automotive Connectivity

#107

Post by matrix2003 »

bryanlarsen wrote: post #52
matrix2003 wrote: post #35

Earlier quoted context omitted.

As mentioned in another comment, it’s also close to the safety limit for low voltage systems. IMO solar pioneered (in recent history) 48V DC systems, which is an easy multiple of 12V to stay below the 50V “high voltage” safety threshold. It allowed people to use smaller gauge wire and chain together multiple 12V batteries that are readily available.

Telephony has been using -48V as a line voltage for a very long time, probably > 100 years.

Is that for power deliver, or signaling?

Re: Standardizing Automotive Connectivity

#108

Post by plorg »

Aloisius wrote: post #30
FriedPickles wrote: post #12

> LVCS...is available in industry-standard light blue Is this tongue-in-cheek, or is there a reason manufacturers care about the color?

They tend to color-code connectors in vehicles by voltage for safety reasons. Light blue is used for 48V.

Meanwhile 12V connectors turn up in a wide variety of grey, where different colors might just mean the connector is keyed differently.

Re: Standardizing Automotive Connectivity

#109

Post by Kirby64 »

typewithrhythm wrote: post #104
cyberax wrote: post #101

Earlier quoted context omitted.

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.

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.

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…
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