151–160 of 182 posts
> Tesla invites all device suppliers and vehicle manufacturers to join us in this initiative. This is not a standard in the sense that engineers use the term. Tesla is hoping it will be adopted as a standard and since Tesla doesn't appear to want to involve any standards bodies, Tesla appears to only be interested in making these connectors a de-facto standard. In any case, that is not a standard.
Those look much like AMP automotive connectors. Using one kind of unkeyed connector in a car may be a bad idea. Things can be plugged in wrong during repairs. There's a lot to be said for making connectors not fit where they shouldn't. Especially in automotive, where many connectors are plugged in blind, by feel. This simplifies manufacturing at the cost of repair. If it can be plugged in wrong, it will be plugged in…
Actually there’s two paths: first the traditional path of different unique wiring harnesses and various signals with unique connectors, or second a common power and coms bus design. If the Cybertrucks electrical ethos is followed by others there’s only 48V and Ethernet. Ethernet doesn’t care or fry if plugged into a wrong port. Any complex wiring can be done inside a part or component as needed, but the interface is…
I'm looking at the electrical schematic [1] and 'eth' appears 107 times while 'CAN' appears 805 times.
And if you think about it, you probably don't want your brake-by-wire system to share a bus with your sound system and your trunk latch for obvious reasons.
[1] https://service.tesla.com/docs/Cybertruck/ElectricalReferenc...
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Why would you need 10 Gb/s speeds in a car
10 Gb/s is not all that much for cameras. Enough for one 60 Hz 4k 14-bit depth camera transmitting raw bayer data. 60 Hz * 3840 * 2160 * 14bit is 6.96 Gbps.
What you'll actually be sending is a high bitrate mpeg stream, probably 54Mbps or thereabouts, you could probably fit 50x camera streams on a shared 10Gbps bus.
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CAN to PC adapters are a few hundred dollars, it isn't causing much friction.
With ethernet you can probably run the car software in containers. I can imagine a container to simulate each hardware unit, a small inter-contaner lan, and develop code that way.
I think the bigger factor is that innovation in the CAN ecosystem has been lagging behind Ethernet for decades now. Only reason it's had such staying power is industry inertia.
1. https://netmodule-linux.readthedocs.io/en/latest/howto/can.h...
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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.
There is no free lunch. You need to go to a finer wire strand, better insulation, better loom, better support for the harness etc, if you want that super fine wire to last. Some of those have pretty direct labor cost impacts too. That's gonna kill a lot of your cost savings, especially at lower production volumes where the design cost is harder to amortize. There's no free lunch.
It's very, very hard to get insulation that's not good for at least 100V and I suspect that just about any generic wire is good for more like 300V.
The only exception that comes to mind is wire that's specifically for "household low voltage" like 24V AC for thermostat, doorbell, sprinklers, landscape lighting. Also normal ethernet. But these are almost all what you'd call signalling wiring rather than power wiring.
Your average hook-up wire that you could buy at the auto parts store to make some repairs is almost certainly rated for 300V already. Mostly because of chafe resistance. Wikipedia says that the dielectric breakdown strength of PVC is 40 millions volts per meter https://en.wikipedia.org/wiki/Polyvinyl_chloride.
Divide both sides by 1 million and you get 40 volts per micron. OK so you need 1/3 of a micron to insulate enough for 12V and you need 1.25 microns for 48V. Now let's have a reasonable safety factor of say 10 or so and we're looking at 3 microns vs 12.5 microns. The only wire I can think of that might have insulation that thin is enamel coated magnet wire for the inside of motor windings. But even that is probably thicker.
Any kind of plastic insulation is going to be significantly thicker than this just to be able to be coated onto the bare copper wire and stick.
You're not wrong that the insulation needs to be thicker as the voltage goes higher. But you're unaware of just how ridiculously over-insulated everything already is due to other constraints of manufacture.
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Actually there’s two paths: first the traditional path of different unique wiring harnesses and various signals with unique connectors, or second a common power and coms bus design. If the Cybertrucks electrical ethos is followed by others there’s only 48V and Ethernet. Ethernet doesn’t care or fry if plugged into a wrong port. Any complex wiring can be done inside a part or component as needed, but the interface is…
> If the Cybertrucks electrical ethos is followed by others there’s only 48V and Ethernet. I'm looking at the electrical schematic [1] and 'eth' appears 107 times while 'CAN' appears 805 times. And if you think about it, you probably don't want your brake-by-wire system to share a bus with your sound system and your trunk latch for obvious reasons. [1] https://service.tesla.com/docs/Cybertruck/ElectricalReferenc...
Earlier quoted context omitted.
There is no free lunch. You need to go to a finer wire strand, better insulation, better loom, better support for the harness etc, if you want that super fine wire to last. Some of those have pretty direct labor cost impacts too. That's gonna kill a lot of your cost savings, especially at lower production volumes where the design cost is harder to amortize. There's no free lunch.
> better insulation It's very, very hard to get insulation that's not good for at least 100V and I suspect that just about any generic wire is good for more like 300V. The only exception that comes to mind is wire that's specifically for "household low voltage" like 24V AC for thermostat, doorbell, sprinklers, landscape lighting. Also normal ethernet. But these are almost all what you'd call signalling wiring rather…
Earlier quoted context omitted.
> If the Cybertrucks electrical ethos is followed by others there’s only 48V and Ethernet. I'm looking at the electrical schematic [1] and 'eth' appears 107 times while 'CAN' appears 805 times. And if you think about it, you probably don't want your brake-by-wire system to share a bus with your sound system and your trunk latch for obvious reasons. [1] https://service.tesla.com/docs/Cybertruck/ElectricalReferenc...
What are the obvious reasons?
Earlier quoted context omitted.
Why would you need 10 Gb/s speeds in a car
Why would you not? Tesla is sending even the infortainment data stream through that bus. It's incredibly helpful having all data travel on a singular wire because you can tap in at one point and read it all out. Makes the entire system significantly easier to debug, understand and develop against.