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Featured Automotive 12v vs 48v Architecture ?

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by hill, Dec 8, 2023.

  1. hill

    hill High Fiber Member

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    The last time voltages were changed over was over ½ a century ago - when the Automotive industry went to 12 volt over 6 volt. The rationale to switch over to 48v is extensive - but of course that would mean a lot of the peripheral electronics that use it would have to be upgraded & thus the switch over has been met with resistance (no pun intended).
    Cybertruck incorporates 48v instead of 12v. Tesla just released all their documentation to the competition which will bring its changeover more affordably if when the competition also incorporate it.

    'Great For The Industry': Ford, Others Get Tesla Cybertruck 48V System Specs

    Hopefully domestic Manufacturing won't drag their feet & let the Asian countries Master this long before the USA
    .
     
  2. bisco

    bisco cookie crumbler

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    when is tesla switching all their vehicles?
     
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  3. bdc101

    bdc101 Member

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    You said "the benefits are extensive" but what are the benefits other than making power wires slightly smaller gauge? The article didn't have any more information. It seems like this change would only be worth a few pounds per vehicle.
     
  4. ChapmanF

    ChapmanF Senior Member

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    Lighter electric motors too, for steering and such.
     
  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    About the time I replace my 12V buss, 2019 Model 3. <GRINS>

    Bob Wilson
     
  6. bdc101

    bdc101 Member

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    That only applies to a couple of small motors on the car though - steering, HVAC, the battery fan, etc. Maybe the brake booster, I imagine that is run on low voltage, but I'm not really sure. We are probably talking about a pound or two per vehicle. All the powertrain MG units won't be affected. And the inverter wouldn't be any different.
     
  7. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Right, but it's only a few pounds of some of the most expensive materials in the car. Times hundreds of millions of cars.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    I have a vague memory that some Toyota vehicles with electric-motor power steering are already running it from its own DC/DC converter at 48 volts, but I don't remember which ones or where I saw it, so grain of salt. That motor needs to have some serious grunt.
     
  9. bdc101

    bdc101 Member

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    Copper wires are definitely not anywhere close to the most expensive materials in the car. Probably not even in the top ten.

    Compared with designing hundreds of new standard sizes and configurations for batteries, changing around the whole supply chain, retooling battery factories all over the world, phasing these new batteries and cars and alternators in over many years (since cars that need 12v batteries will still be around in 20-30 years) etc., and getting all of the automotive manufacturers to agree to that - which they won't, so you will need multiple standards for the same thing for many years. All so we can use a little bit less of highly-recyclable, and highly-recycled copper (a commodity, not a precious or rare metal).

    I would believe that. We have a Mazda with electric power steering, and I assume it is just 12 volts because it's a pretty simple car, but it does have an 80 amp fuse for the power steering.
     
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  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The old GM 'mild' hybrids used a 48 V power system.

    Bob Wilson
     
  11. austingreen

    austingreen Senior Member

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    In a traditional vehicle the advantages are slight. In a vehicle that uses a lot of power like electronic AC, water pumps, electronic power steering, other power electronics like electronic turbo or super chargers, there are advantages to those parts. It does require volume of the other 12V parts. Because of safety concerns a 48V hybrid might be significantly less expensive, with higher voltages for plugins.
     
  12. hill

    hill High Fiber Member

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    Sorry, should have posted supplemental info regarding 48V benefits;

    48 volt: what it is and why it&#039;s an important innovation | Dalroad
    .
     
  13. Georgina Rudkus

    Georgina Rudkus Senior Member

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    It's another way to exclusive limited supply parts that will be more expensive than widely available generic 12 volt parts.

    48 volt cables would require more complex shielding from 5 volt digital devices used in computer control modules that can be fried more readily "fried" when coming in contact with voltages.

    That has cause devastating results that have cost loss of life in commercial aircraft accidents.
     
  14. jdenenberg

    jdenenberg EE Professor

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    This would create a large market for 48V to 12V DC buck converters.

    JeffD
     
  15. hill

    hill High Fiber Member

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    You could step down voltage however you wanted to - off of a large traction pack & not even need a 12v (or 48v) battery. During collisions high voltage is chopped from the large pack, so there would still need to be some low voltage access for emergency flashers Etc in that case. One wonders if the Freak Out was as severe when the industry went from 6V to 12v
    Ford's CEO seemed quite excited about it. Yet it looks like people's hair start to catch on fire at the notion of what they might worry about ... like ecu's ... shielding & other computer type goodies.
    Refresher;
    why musk does much of the stuff he does in manufacturing ... improvements & cost savings.
    .
     
    #15 hill, Dec 8, 2023
    Last edited: Dec 8, 2023
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  16. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Be prepared to pay $400 for a replacement starter battery. We all complain about paying $200 for a battery for the Prius that most of us here own.
     
  17. bdc101

    bdc101 Member

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    Does 48v DC really need to be shielded from DC any more than 12v currently is? It's still DC just lower amps, seems like it would require less care if anything.
     
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  18. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I guess I look at a finished wiring harness as considerably more valuable than its constituent copper, by the pound anyway.
     
  19. ChapmanF

    ChapmanF Senior Member

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    The copper's the only constituent there'd be less of. The rest is all insulation and chafe protection and terminals and connectors.

    They already minimize the copper as much as they can, by using the crazy thin high temperature automotive insulation, allowing angel-hair-thickness wires that would horrify any electrician used to 90℃ house wiring.

    At 48 V they could make the copper even thinner ... but they might have to make the insulation 4✕ thicker.
     
  20. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Rats will get a kick out of it if the insulation is soy based. Sparks at 48 volts would more likely cause fires.