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Running a Tesla after Irene took the power

Discussion in 'News' started by mpt, Sep 6, 2011.

  1. mpt

    mpt Electrics are back

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  2. TEG

    TEG TMC Moderator

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    Excellent write-up!
     
  3. mpt

    mpt Electrics are back

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    Cheers!
     
  4. tomsax

    tomsax Member

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    Great story! Around here when the power goes out, the gas stations don't work either, which is a harder problem to solve since it's inconvenient to move the gas station to a working outlet.

    I just wrote up a similar story about the ubiquity of outlets compared to gas stations: Where Do You Gas Those Things Up?

    Depending on your driving needs, even those boring old 120V outlets can get the job done.

    And remember kids, you don't need a full charge to drive your car, just sufficient charge to get you to where you're going and the next charging location.
     
  5. mpt

    mpt Electrics are back

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    That's something that I learnt this last week; charging up the car to just 15 miles means I'll be home, as normal, no problem... with a buffer!

    I used to have range anxiety, as much as I denied it. Now, I have "Range Confidence".
     
  6. Doug_G

    Doug_G Lead Moderator

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    I think that's true pretty much everywhere. You couldn't get gasoline here during the Northeast Blackout of 2003. Once partial power was restored there were long lineups.

    Of course electric power was constrained afterwards. Most of the nuclear plants scrammed, and it took weeks to get some of them back online. But that was more of a problem for peak load; I suspect some electric car charging could have been done late at night. Of course there were almost no electric cars around at the time.
     
  7. Doug_G

    Doug_G Lead Moderator

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  8. suxxer

    suxxer ElektroVolt

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    #9 suxxer, Sep 6, 2011
    Last edited: Sep 6, 2011
    I don't wanna spoil the great thread, but did you notice the J1772 here:
    (I didn't say anything about the sign in the back... ;)

    [​IMG]
     
  9. W.Petefish

    W.Petefish Active Member

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    In the word of Riddick: "Interesting."
     
  10. mpt

    mpt Electrics are back

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    One day I'll convert it :)

    No, not doing a TG here; that was the adjacent spot;

    Here are some of the pics that didn't make the cut

    Flat.jpg J1772.jpg
     
  11. Slackjaw

    Slackjaw Member

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    Michael, you mentioned in another thread that you had solar water heating and were considering upgrading to solar PV for your electricity. Do you think that would have helped in this instance? I think it was pretty cloudy for the first day or two after Irene so you might have needed a huge array to recharge a car. I'm waiting to see an article like yours from NigelM along these lines but it seems that Florida gets less blackouts than we do in NJ. I'm just curious as to whether you've run the numbers. I'm sure it crossed your mind during this little "adventure"...
     
  12. mpt

    mpt Electrics are back

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    The solar PV system would normally feed into the grid... and be consequently shorted out into the impossible load of all the houses without power. I could re-wire it temporarily and have it feed into the cars. If I had a big 6KW array, guesstimate 5 hours at 5KW mid-day, a couple at 3KW (big guessing going on here) that's enough to put 9 miles/hour into the car, so, yes, 45 miles a day would more than cover my commute.

    However, the car would be at the office with me... bugger. Could swap cars over each day though, charge one, take the other. Could work.
     
  13. rabar10

    rabar10 FFE until Model 3

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    All grid-tied systems (if installed to code) must disconnect from the grid when the utility-side voltage falls outside of acceptable parameters, i.e. under- or over-voltage or frequency mismatch. This is a safeguard for utility personnel trying to service lines outside your home during outages etc.

    Grid Tie Solar Systems

    Then the question becomes whether you could install a system, without batteries, that could run the inverter in isolation from the grid and attempt to charge your cars or power a portion of your home on its own when power is available from the array. I think that would be very difficult to pull off (without using a DC battery buffer prior to the inverter). But I could be wrong...
     
  14. Doug_G

    Doug_G Lead Moderator

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    Right. I really doubt the solar power source would be stable enough to charge a car. Every time a cloud goes by the voltage will sag, and then the charger will trip off. The solar system would have to be oversized, and the car set to minimum charge current, to have any any chance of it working for more than a few minutes. Unless you just happened to have a "severe clear" day.
     
  15. mpt

    mpt Electrics are back

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    Sounds like batteries in line would be essential. Big expense & a reduction in system efficiency. Oh well, I guess it's too soon to go off grid.
     
  16. rabar10

    rabar10 FFE until Model 3

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    The irony in this is that the EV is already a big DC battery buffer, of course. But because almost all charging systems are tied to utility power formats (AC, constant voltage/frequency, etc.) it becomes a pretty big headache.

    OK, who wants to build a "solar emergency" CHAdeMO charger that ties directly to a solar array? Bypass the AC step completely, and simply allow the DC output current to vary based on what's available from the solar array... (sorry, going a bit off-topic)
     
  17. W.Petefish

    W.Petefish Active Member

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    I did a cost survey on it. It would take approx 37 SLA (sealed lead acid) batteries to make the 440v DC. to power a CHAdeMO for 45 min would take at least twice that. At $219 / battery, thats $16,206 just for the batteries.
     
  18. rabar10

    rabar10 FFE until Model 3

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    I mean to skip the external batteries entirely -- simply use existing peak-power-tracking DC/DC converter electronics to generate the required DC voltage for charging the car directly from the solar array itself.

    I don't know enough about the CHAdeMO protocol to know if the car would accept a varying current based on what was available from the solar array, but from a power electronics point of view it would work fine. This is exactly how our solar-powered car worked back in college (minus the CHAdeMO protocol step)
     
  19. W.Petefish

    W.Petefish Active Member

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    Won't work. You need to sustain 440V at 200A DC for 45 min for CHAdeMO. (or any LV 3 for that matter)
     

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