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90 amps for electric car charge!

Discussion in 'Electrical Engineering' started by Bill, Feb 15, 2010.

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  1. Bill

    Bill Guest

    Is your garage electric car ready?

    Seems these cars can be charged with a regular 15 amp outlet, any 240 volt
    outlet (50 amps best), or a 90 amp "4 hour charge" connection...
    http://www.teslamotors.com/electric/charging.php

    Vehicle-to-grid (V2G) describes a system in which electric or plug-in hybrid
    vehicles communicate with the power grid to sell demand response services by
    either delivering electricity into the grid or by throttling their charging
    rate...
    http://en.wikipedia.org/wiki/Vehicle-to-grid

    Cities Prepare for Life With the Electric Car...
    http://www.nytimes.com/2010/02/15/business/15electric.html
     
  2. ? <> ?????? ??? ??????

    <snip>
    Yeah, I've read in a german magazine (www.spiegel.de) that even the best car
    battery has no more energy than 2 pints of gas. To become viable, they have
    to be 3 times as good and 3 times as cheap. Not to mention, that if you put
    the pedal to the metal, the bat will drain in very little time. And of
    course, it's worse efficiency to burn coal, generate electricity and
    transmit, distribute it etc. over 5-6 transformation stages than using an
    ICE with gasoline...
     
  3. bud--

    bud-- Guest

    Interesting choice for comparison since the Prius is a hybrid (partly
    electric) car. It is likely to include an option to charge the
    (relatively small) battery off the grid in the not-too-distant future.

    From what little I have seen, the Tesla is a sports car - high
    acceleration, probably better high speed behavior.
     
  4. Doug Miller

    Doug Miller Guest

    Moving the pollution from one place to another is, in itself, a laudable goal;
    seen what the air looks like in LA or Chicago recently?
    You're overlooking a few points in favor of the electric cars. First off, by
    concentrating the emissions at the power plant, the air quality in most major
    cities will be tremendously improved. Second, again by concentrating the
    emissions in one place, it's easier to scrub them; one power plant producing
    the electricity to power a million electric cars will likely produce much less
    pollution than a million cars with internal combustion engines. Third, one
    large power plant has the potential for economies of scale that a million
    point sources lack. Fourth, and perhaps most important, the internal
    combustion engine is terribly inefficient, since it derives all its power from
    the mechanical energy of the expanding exhaust gases and wastes all of the
    heat; coal-fired power plants are *far* more efficient.
     
  5. Bill

    Bill Guest

    I see a nice marketing opportunity for SquareD, et al, to bring out
    No, no, no!

    Dad's car, mom's car, son's car, daughter's car = 360 amps additional to the
    current 200 amp service or 560 amps give or take...

    (Forget about the eight is enough family!)

    And how about a 400 car parking garage downtown, each space with a 90 amp
    circuit?
     
  6. Bill

    Bill Guest

  7. Rich.

    Rich. Guest

    It's a 90A Circuit Breaker. However, the maximum current for the vehicle is
    70A, as set by the duty cycle of the Pilot waveform.
    At 240v that is 16.8 kw*4 to do a full charge, or 67.2 kw total. At the
    national average of $.12 per kw that is about $8 ($.04/mile) for a full
    charge to drive those 200 or so miles. This is about 1/3 the cost to drive
    an average gas vehicle at 20 MPG and $2.60 per gallon.
     
  8. When I go camping, I bring my zero emissions
    electric heater for my tent. I plug it into the
    generator that burns oil, and pumps out carbon
    monoxide. But, the heater is zero emissions.

    Same deal with the car. Except that manufacturing
    of the car pollutes, and that the batteries
    eventually have to be thrown out, and, and, and.

    --
    Christopher A. Young
    Learn more about Jesus
    www.lds.org
    ..




    The second big omission is that you always hear
    the media gushing over
    this cars as "zero emissions". Which is true
    only if you
    conveniently ignore that all this power still has
    to be generated
    someplace.
     
  9. Doug Miller

    Doug Miller Guest

    You have that incorrect and backwards. We're using fission power *now*; fusion
    is still in the future. And it won't be radiation-free by any means.
     
  10. James Sweet

    James Sweet Guest


    Sounds about right. There's no getting around the fact that it takes a
    lot of energy to move a car, figure you typically need say 20 horsepower
    at cruise on the highway, that's roughly 20kW assuming ~85% efficiency
    of the motor and controller. That means about 20kWH per 60 miles of
    range, and charging the batteries is not 100% efficient either. Whatever
    energy you take out, you have to put back in and you can only pull 1.8kW
    from a 15A 120V receptacle. 90A for four hours is about 86kWH, so
    about 250 miles of highway cruising.
     
  11. James Sweet

    James Sweet Guest


    Electric cars are certainly not the end-all be-all solution to our
    problems, although they do offer advantages. A large stationary
    generator operating steady at near full capacity is much more efficient
    than a bunch of individual car engines, even if the generator is burning
    fossil fuel. It also centralizes emissions in one place rather than
    spewing nasty stuff into the stagnant air in city streets.

    If the cost came down, I wouldn't mind having an electric commuter car.
    I wouldn't get rid of my gasoline car, but for the 16 miles a day I
    commute, something that could go 40 miles on an overnight charge would
    let me go to work and back and have enough range to go get some lunch.
     
  12. Bill

    Bill Guest

    Well I'm getting out my popcorn to sit back and watch the show in California
    with this. They [California] had a fit with everyone buying those new TV's
    which use a bit more energy. (Overloading the electric grid.) In California
    no one wants any new major electric transmission lines built in their
    backyard.

    If quite a few people buy these cars in California, it will be interesting
    to see what they do when it places a strain on their electric grid.
    Neighborhood nukes?

    Or for that matter if there was a concentration of these new cars in one
    neighborhood anywhere. Say 3 homes all on the same electric company
    transformer. Then all 3 homes get electric vehicles, and they all recharge
    them at 6:00 pm when they get home on a hot summer day, and also have their
    AC and everything else going full blast???

    Neighborhood Nuclear Power...
    http://www.hyperionpowergeneration.com/about.html
     
  13. The last one is a good example of the law of unintended results.

    TDD
     
  14. George

    George Guest

    Aren't you assuming worst case? I think a lot of diversity will be
    involved. Many would likely just use a longer term lower current draw
    charge.
     
  15. Doug Miller

    Doug Miller Guest

    That solution's already here: nuclear.
     
  16. Tony

    Tony Guest

    And a lot more people would be going to off peak rates so they don't
    start to recharge until people are going to bed.
     
  17. I remember the Toshiba Corporation small reactor project for Alaska. I
    wonder how it's going?

    http://www.nrc.gov/reactors/advanced/4s.html

    TDD
     
  18. ? <> ?????? ??? ??????
    Your math is incorrect. Charging at 90amps, 240V for 4 hours is
    86Kwh of electricity. At 10c a KWH that would be $8.60. Here in
    NJ, at about 17c, it would be $15.

    Also, the compare can't be made to a internal combustion engine car
    getting 20MPG. The electric cars are very small cars. So, it should
    be compared to cars getting 35-40 MPG. You can get a bluetec
    Mercedes diesel in that range that is a real car. There are plenty
    of other small cars capable of that mpg too, So assuming 35mpg, I
    could drive at least 175 miles in a simlar car for the same $15 in
    energy cost. And those electric energy costs are largely derived
    from cheap coal from existing plants which are not particularly
    clean. If we're to build anything remotely clean, ( think carbon
    sequestration) you can expect the future energy prices to be way
    higher. Unless we come up for a solution on how to make the
    electricity, you can't begin to compare costs moving forward.




    Oh, and BTW, not to mention situations when the vehicle's lights are on, or
    when you need heating or even a/c;then the battery would be dead even
    sooner. (Or just turn the car radio on).
     
  19. This point can't be emphasized enough, as it's true that the pinhead
    media always seems to get this one wrong and leaves the mistaken
    impression that "green" electric cars run on pixie dust or some such.

    Just last night I heard a local news report about recovering methane
    from landfills for use as fuel. While this is a good thing overall, the
    stupid reporter (or editor) got away with saying that this would reduce
    carbon dioxide emissions! Of course this is totally untrue: while the
    methane would be captured instead of simply venting to the atmosphere,
    the carbon dioxide would be released later when it was burned. All
    that's being done is delaying the release of the CO2. Sheesh; are we
    *really* that much a nation of idiots?

    Now, you and I are on opposite sides of this debate in lots of ways
    concerning the overall viability of renewable energy, nuclear power,
    etc. But I agree 100% with you here. Such stupid oversights on the part
    of the media (and even on the part of some who promote green energy) can
    only set things back.
     
  20. daestrom

    daestrom Guest

    'Worse efficiency' but it could still cost less to the consumer. And
    not all electricity comes from coal.

    daestrom
     
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