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electrical specs for charging main battery

Discussion in 'Gen 2 Prius Technical Discussion' started by sjk, Jun 27, 2006.

  1. sjk

    sjk New Member

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    Does anyone know the range of voltages and currents that
    are used, or could theoretically be used,
    to charge the main battery?

    I'm asking because I'm wondering, for example, what kind of
    electricity the guys who try adding solar collectors, or plug-in mods,
    have to make in order to successfully charge the battery.
     
  2. hobbit

    hobbit Senior Member

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    See http://techno-fandom.org/~hobbit/cars/tds-priups/
    We charged from a Vicor 300V DC supply using a 500W halogen worklight
    as a dropping resistor -- about 30 ohms if the filament was hot,
    feeding about 3.5 amps into the battery. With a cell capacity of
    6.5 Ah that would fully charge the pack in less than two hours. Such
    a lashup could be and indeed has been used to bring a "discharged
    Prius" back to life without Toyota's supposedly mucky-muck special
    HV charger, but you'd really want to only charge just enough so the
    HV battery could come online and start the engine and then let the
    car and the BMS take over to finish the job with proper monitoring.
    .
    The plug-in-mod guys aren't charging the stock HV battery, they're
    charging additional ones.
    .
    As far as charging rate -- on a high-speed all-regen slowdown or a
    long downhill, you can charge at close to the 100A limit and the
    battery just takes it. Heats up a bit at those current levels, but
    the cells can deal and reaching 80% "full" capacity happens pretty
    quickly.
    .
    _H*
     
  3. tochatihu

    tochatihu Senior Member

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    When Julian Edgar burned up his Prius NiMH battery, I think he let it have about one amp overnight. Don't be doin' that!
     
  4. hobbit

    hobbit Senior Member

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    Right, because amp-hours do NOT add up in a string...
    .
    _H*
     
  5. sjk

    sjk New Member

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    Thanks. You say:
    So, what voltage do you think you actually applied to the battery?

    I take it from this and the post about the 1 Amp overnight battery destruction that
    current isn't so much the issue (at least up to 100A),
    but that you have to be careful not to charge the battery
    beyond a certain limit then, right?
     
  6. Cheap!

    Cheap! New Member

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    <div class='quotetop'>QUOTE(sjk @ Jun 27 2006, 10:56 AM) [snapback]277383[/snapback]</div>

    I am right there with you, this is my hot topic too. I have done some research on the topic and I have some general information on it. It is like having a key and not knowing where the lock is. I want to mod my car with solar and give free directions on how to do it to anyone who will listen.
     
  7. hobbit

    hobbit Senior Member

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    Search for prior threads on this. It is generally held that the
    amount of energy you get from an onboard solar array is miniscule
    compared to what's needed to push the car any appreciable distance.
    House rooftop array, that's different, but even if you manage to
    pull 250W from a cartop array that still only gives you about one
    free mile per hour of insolation.
    .
    _H*
     
  8. ken1784

    ken1784 SuperMID designer

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    <div class='quotetop'>QUOTE(hobbit @ Jun 28 2006, 01:18 AM) [snapback]277395[/snapback]</div>
    Above method is not recommended.
    We have to watch/control the battery SOC level not to exceed the 80% level, otherwise you'll see very short battery life.
    Please take care of the battery system with professional manners.

    Ken@Japan
     
  9. hobbit

    hobbit Senior Member

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    It's okay. That whole experiment was sort of a hack in the first
    place, and we didn't let the pack voltage get any higher than 235.
    Jim's pack is unlikely to find its way back into a car anytime soon.
    If I was trying to recover a discharged one in a car, again, I'd
    charge only enough to get the system started and then let the BMS
    take over from there. But part of the point is that with proper
    care, you *don't* need Toyota's fancy charger that there are maybe
    two of in the entire CONUS, etc etc.
    .
    _H*
     
  10. sjk

    sjk New Member

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  11. statultra

    statultra uber-Senior Member

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  12. ken1784

    ken1784 SuperMID designer

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    <div class='quotetop'>QUOTE(statultra @ Jul 1 2006, 01:39 AM) [snapback]279161[/snapback]</div>
    I now know you did that.
    However, the point is how did you watch/control/maintain your battery SOC level?

    Ken@Japan
     
  13. psibill

    psibill Junior Member

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  14. ScottY

    ScottY New Member

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    From their website,
    That's 0.288 horsepower.