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posted by Fnord666 on Monday February 26 2018, @12:12AM   Printer-friendly
from the shocking-news dept.

Car companies, starting with Volvo last summer, have laid out plans to electrify entire lineups of vehicles. But the fine print makes it clear that the coming decade and beyond will focus not just on massive battery packs powering electric motors, but also on adding a little extra juice to the venerable internal combustion engine.

Increasingly, that juice will arrive in the form of new electrical systems built to a 48-volt standard, instead of the 12-volt systems that have dominated since the 1950s. Simpler than Prius-type drivetrains and less expensive than Tesla-scale battery power, the new electrical architecture both satisfies the demands of cars made more power hungry by their gadget load and enables the use of lower-cost hybrid drive systems.

https://www.nytimes.com/2018/02/08/business/electric-cars-48-volts.html


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  • (Score: 2) by Grishnakh on Monday February 26 2018, @06:32AM (13 children)

    by Grishnakh (2831) on Monday February 26 2018, @06:32AM (#643791)

    Thinner wires but thicker insulation due to safety regulations.

    Doubtful. Typical wire jackets can already handle hundreds of volts (probably 600V), so 12V -> 48V isn't really a change, unless the OEMs are getting special wire with thinner insulation than usual. (i.e., If you go out and buy some wire right now, there's no such thing as "12V wire"; it all handles voltages far above anything you're likely to throw at it. Wire with insulation for only 12V would be ridiculously fragile anyway, since you don't need much insulation for such low voltage.) Even if they are using thinner-insulation wire, insulation doesn't add significant cost, unlike copper.

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  • (Score: 2) by sjames on Monday February 26 2018, @06:39AM (8 children)

    by sjames (2882) on Monday February 26 2018, @06:39AM (#643795) Journal

    I'm thinking more for mechanical requirements rather than electrical.

    • (Score: 2) by Grishnakh on Monday February 26 2018, @04:29PM (7 children)

      by Grishnakh (2831) on Monday February 26 2018, @04:29PM (#643999)

      Here again, you're not making much sense. They *already* use a particular amount/type of wire insulation in cars for mechanical reasons, rather than electrical, because cars are a harsh environment (lots of vibration), and the voltage is extremely low. Changing to 48V isn't going to affect that significantly. 48V is still low-voltage, and the mechanical requirements are the same.

      • (Score: 2) by sjames on Monday February 26 2018, @06:54PM (6 children)

        by sjames (2882) on Monday February 26 2018, @06:54PM (#644087) Journal

        And if you use a smaller gauge wire, you have to replace that with something.

        • (Score: 2) by Grishnakh on Monday February 26 2018, @07:46PM (5 children)

          by Grishnakh (2831) on Monday February 26 2018, @07:46PM (#644126)

          Why are you so argumentative on this topic? If you use a smaller gauge wire, you just use a smaller gauge wire. They already have small-gauge wires in cars (for ultra low-current signal lines); it's not like they have to go find something new. They have a whole range of wires they already use, now they just use more of the smaller stuff and less of the larger stuff.

          • (Score: 2) by sjames on Monday February 26 2018, @09:08PM (4 children)

            by sjames (2882) on Monday February 26 2018, @09:08PM (#644197) Journal

            I'm replying because you're replying. Why are YOU so argumentative on this topic?

            • (Score: 2) by Grishnakh on Monday February 26 2018, @09:35PM (3 children)

              by Grishnakh (2831) on Monday February 26 2018, @09:35PM (#644216)

              Because you keep coming up with things that aren't really problems with converting to 48V and claiming that they are, that's why. The ideas you have are simply wrong: wiring insulation is not a significant factor, redesigning parts and intentionally sticking with 12V when it's no extra work to design for 48V is stupid and not going to happen. In this thread, you really seem to be hung up on wire insulation for some odd reason. What is your obsession with this? Do you just *have* to get the last word in? There's no difference in wire for 12V or 48V systems, I've said it over and over.

              • (Score: 2) by sjames on Monday February 26 2018, @11:31PM (2 children)

                by sjames (2882) on Monday February 26 2018, @11:31PM (#644304) Journal

                Problems? I have presented no problems, just likely solutions for the transitional period as automotive systems transition to 48V. I do hope they don't cheap out on the wires. And there's no reason that can't save some copper and still have adequate mechanical properties.

                Why do you expect a conservative industry to re-design the entire electrical system in one shot when they don't have to?

                • (Score: 2) by Grishnakh on Tuesday February 27 2018, @03:05AM (1 child)

                  by Grishnakh (2831) on Tuesday February 27 2018, @03:05AM (#644432)

                  Why do you expect any industry to re-design something major and stick with an obsolete standard instead of just moving to the new standard that they've already adopted?

                  • (Score: 2) by sjames on Tuesday February 27 2018, @04:25AM

                    by sjames (2882) on Tuesday February 27 2018, @04:25AM (#644462) Journal

                    Because that's how it tends to be done. It spreads risk as well as engineering effort and part validation. Given that there are so far no deployments, how much testing of a 48v window motor do you suppose is available? Everything I have read indicates that the intention is very much to use a DC-DC converter for all of the accessory systems and even the engine controller. See these [jalopnik.com] links [assemblymag.com] for example.

                    Beyond that, I doubt they will go 48v on all models in the first year. They'll want to use the same parts as much as possible across the line.

                    As I said, they will likely EVENTUALLY move other parts over to 48v, but that will be a while.

  • (Score: 3, Informative) by anubi on Monday February 26 2018, @07:15AM (3 children)

    by anubi (2828) on Monday February 26 2018, @07:15AM (#643807) Journal

    I just hope they don't start using aluminum wire!

    Looked at any modern washing machine motors? Aluminum wire! With orange lacquer so it LOOKS like copper.

    I found that out when I decommissioned a machine with a rusted out tub. While I did recover several handfuls of nice colored wire for my projects, what became a firepit, and a mount for a sink I wanted for the back yard, I had kept the motor as a donor for copper wire that I like for things like tying plants. To my chagrin, when I ground the motor open to get to the wire wound on the stator, the wire itself was aluminum!

    No problem for me, and the motor did not fail because of this, but I found it interesting that the motor was wound with orange-lacquered aluminum wire. Pretty obvious when I took a small file to it.

    Also, note a lot of the "Heavy Duty 4 Gauge Jumper Cables" look like copper. Look for "CCA". I know, we automotive types see CCA and think "Cold Cranking Amperes". That's not what the manufacturer of those cables meant. "CCA" is their term for "Copper Clad Aluminum". That's right, Aluminum wire in your battery jump cables. That nice low-gauge rating may not mean as much as you was hoping it meant.

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
    • (Score: 2) by deimtee on Monday February 26 2018, @10:24AM (2 children)

      by deimtee (3272) on Monday February 26 2018, @10:24AM (#643868) Journal

      Aluminium is less ductile and less dense than copper, but per linear mass is both stronger and a better conductor. Per unit volume copper is almost twice as good as a conductor, but is three times heavier.
      Fixed wiring as in a motor probably should be aluminium, it would reduce the total weight.
      One of the main reasons for not using it is actually the problem of terminations. It is difficult to reliably connect to as the surface oxide layer is basically sapphire. CCA sounds like an interesting solution to that.

      CCA Jumper cables, yeah those cheating fuckers need a few CCA's through their privates. Aluminium wire will crack if repeatedly flexed as happens to jumper cables.

      --
      If you cough while drinking cheap red wine it really cleans out your sinuses.
      • (Score: 2) by Grishnakh on Monday February 26 2018, @03:53PM

        by Grishnakh (2831) on Monday February 26 2018, @03:53PM (#643974)

        Fixed wiring as in a motor probably should be aluminium, it would reduce the total weight.

        I doubt that. Motors have two main parts: the windings and the core (this applies to both the rotor and the stator, though some motors omit windings in the stator and use permanent magnets). The core is usually made of thin laminations of iron, and is used for conducting magnetic flux. Using aluminum windings would require you to significantly enlarge the whole motor, including the core, which means you'll be adding a bunch more mass in iron, which is even more dense than copper.

        Iron is cheap, though, so for cost-sensitive applications where you care more about cost than size, and weight isn't a big concern, it can make sense. A laundry machine is a good example of such an application: heavier is actually better here usually (modern washers actually add concrete to increase mass), and there's generally plenty of room for a motor. But in a car, even if the motors weigh the same, size is much more important than shaving a few pennies of cost.

      • (Score: 2, Informative) by Anonymous Coward on Monday February 26 2018, @04:25PM

        by Anonymous Coward on Monday February 26 2018, @04:25PM (#643996)

        CCA Jumper cables, yeah those cheating fuckers need a few CCA's through their privates. Aluminium wire will crack if repeatedly flexed as happens to jumper cables.

        Copper has the same problem. Neither metal has a fatigue limit -- i.e., both copper and aluminum will inevitably fail under cyclic loading/unloading (no matter how small the load). Aluminum does fail faster, though. If you don't use your jumper cables more than a couple times a year (like most people) then either kind could last a lifetime.

        So as with most things in life, it's a cost/benefit tradeoff. CCA should have a substantially lower upfront cost. It will also weigh less, which might be an advantage (keeping it in your car -> less mass -> less fuel consumed? This effect is probably in the noise).
        On the other hand, aluminum is thicker than copper for the same conductivity, so CCA cables will be physically larger. Also your copper cables will probably be worth something in scrap later while the CCA cables will probably be worthless.