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Toyota engineer explains how long range EV's aren't practical

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Ashlem, Apr 20, 2015.

  1. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    Except that, in practice, you won't ever find such a portable cable that small for that load. You'll only carry that much load with that size as a bus bar, for example.
    I recall from when I was in the Navy that a 500 amp 480v shore power cable was ~3-4 inches in diameter, including insulation. (We'd need one with 4x the area.) See pictures like this:

    File:US Navy 100302-N-2147L-003 Sailors remove a shore power cable aboard SS New York (LPD 21).jpg - Wikimedia Commons

    Mike
     
  2. drysider

    drysider Active Member

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    All of the issues you cited are problems with the grid. California has constant load problems when the weather is hot...to the point of shedding huge segments of the grid. The "dinky" car supercharger needs as much generating capacity as several hundred home air conditioners. One million of these "dinky" loads is many, many gigawatts. I am not on one side or the other in this discussion. If we can move money from the gasoline industry (as EV's become more common), then we can, perhaps, offset the cost of the increased generating capacity. In any case, there is a whole industry devoted to lowering peak load demands.
     
  3. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Hey, I was a sub officer back a long time ago. I did my wrestling with shore power cables. I agree they are not portable, but you can carry a lot of current on smaller cables if the run is reasonable short and you have a high quality conductor alloy. Obviously shore power cables need to be long and correspondingly big to minimize temperature rise and definitely minimize inductive droop. Don't forget that big long sub shore power cables had to have a lot of the size added to keep from inductive tripping low voltage circuits due to load changes on the sub such as securing the diesel. That would not be an issue with a EV recharger that can control load changes gently. A bus bar is exactly what is used when no flexibility is needed, even if the current is a lot less.

    I'm limiting my focus just to the possibilities of a what limits a supercharger station. Conductor problems are straightforward to solve, especially with some sensible automation. Grid problems are a non-issue in reality. It's battery limitations at the technical end and mass market demand at the economic end...and the battery issues are being improved steadily.
     
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  4. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    There is a California grid problem due to state government mismanagement and utility obtuseness. As usual, it is the CA consumer that is punished with both a cranky grid and extremely inflated prices. But the customers are the victims, not the cause. The problem to be solved is 100% political and financial, not technical. As long as utilities destroy their power plants (i.e. San Onofre) the grid problem is susceptible to problems even with a toy EV, much less a supercharging station.
     
  5. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    Me too!

    Of course. But the power has to come from somewhere to get to that short run.
    My points were:
    It isn't practical to do this for a residence.
    And it isn't needed because most people will just charge as night with L1 or L2 anyway

    And as for recharging along the Interstates why go through all this expense (beyond Tesla's superchargers)?
    If you want a 5 minute turn around, just do a battery swap. This allows keeping the battery optimized for low cost and high power density rather than quick charging. (which probably requires different chemistry, more exotic cooling, etc.)
    Note that I think battery swapping is probably a non-starter for at least a decade or more. (If you only rent/borrow the battery you might not take as good care of it as if you own it.) For the next decade, Tesla superchargers are probably good enough -- but everyone needs to standardize on it.

    Mike
     
  6. wjtracy

    wjtracy Senior Member

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    Correct me if I am wrong, CA imports a lot of cheap elec trom outside the state. If CA were generating it's own elec costs would be higher yet. The CA situation does not really scale up too well ...
     
  7. cyclopathic

    cyclopathic Senior Member

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    yes they import from places like Wyoming
     
  8. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Someone that understands big loads and heavy machinery!

    Hopefully, that L2 use would include me before too long.

    Because some folks might pay for it. There is a technology side of the discussion and then a market/economics side. It is amazing the problems solved when money can be made. Supercharging may be one of them. What I don't know is where the economic breakpoints might be and if a future market would find enough folks to pay the cost. So while I think really high speed rapid recharging can overcome present technical limits, I don't know whether 5, 10 minutes or longer would be the targeted time goal due to economic tradeoffs.

    That idea was pursued vigorously by "Better Place" initiative and totally failed. Better Place - Wikipedia, the free encyclopedia Another example where narrow technical solutions are independent of economic sustainability.

    Total agree there.
     
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