3 ms·

Thanks. I had always understood PoE's relatively high voltage as helping deal with the attenuation from long runs of thin copper wire. I couldn't find a succin

by sowbug 9y ago

Thanks. I had always understood PoE's relatively high voltage as helping deal with the attenuation from long runs of thin copper wire. I couldn't find a succinct explanation in the article why cars would benefit from this spot in between merely sending information (digital levels like 1.8, 2.2, 3.3, 5.0, etc.) and using electricity to do "real" work (120V, 240V, 480V, etc.). As I understand your answer, yes, they'd like to use it for work, but not so much as to stray into the range of orange wires. I got the second part of that from the article, but the first part was very hard to extract from it.

twic 9y ago
The specific number of 48V is presumably inherited from telecommunications: https://electronics.stackexchange.com/questions/10851/why-do-pbx-systems-use-48-v https://electronics.stackexchange.com/questions/10851/why-do... There's lots of telecom equipment that works at 48V, so it's presumably cheap and easy for carmakers to find suppliers.
- GeorgeTirebiter 9y ago
  There is practically no overlap between automotive and telecom. When I was at Tesla, we couldn't find even one manufacturer for common use subsystems (e.g. window motors). It's a chicken and egg problem for now. That's why 'everything' is still at 12V.
  - jaclaz 9y ago
    Canot say in the US, but in EU most trucks have (since I can remember) 24 V circuits, so there is anyway a long list of parts at 24 V manufactured.
    - kev009 9y ago
      All US military vehicles (even COTS ones with civilian counterparts like the CUCV and newer) use 24v. So do most heavy trucks.
- kalleboo 9y ago
  I would have assumed it's just because it's a multiple of the current 12V (so you could use shortcuts like wiring 4 existing 12V lamps in series)