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It's the Batteries, Stupid!

Discussion in 'Battery Discussion' started by vfx, May 15, 2008.

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  1. Nik

    Nik Dreaming no more :-(

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    I hope they use wireless charging, because a wall-wart charger with a 2-inch thick cable isn't going to be very portable.
     
  2. bolosky

    bolosky Member

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    I don't think that would be necessary. A regular (US) wall socket is 110V/15A, from which you're allowed to draw 12A continuously, or about 1.3kW. Doing that uses an ordinary size wire (think of the wire on 1.3kW hair dryers, for instance). I just looked, and the batttery in my laptop claims to hold 73 Wh, which at 1.3kW would take between three and four minutes at 1.3kW, even if you make some allowance for charging inefficiencies.
     
  3. Norbert

    Norbert TSLA will win

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    Lithium-Ion Battery Keeps Its Cool - Technology Review

     
  4. doug

    doug Administrator / Head Moderator

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  5. user497

    user497 Member

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    Not sure if anyone saw this article in Wired (Video: Crazy Genius Charges EV by Towing It | Autopia | Wired.com) about a guy that recharged half the battery in his Leaf in just 10 minutes but towing the car and using the regenerative braking (he had to slightly press the brakes to engage the regenerative braking):

    "It’s a tricky maneuver, because depressing the pedal too far engages the brakes, but if you use just the right touch, the regenerative braking will send energy to the pack. Everts got the pack up to 73 kilometers of range, about half of its capacity, within 10 minutes. The downside, however, is the car’s sophisticated energy management system had no clue what was going on, and there are probably all kinds of warranty implications."

    As the article points out, the PEM may have freaked out but why would this recharge the batter so quickly? Could companies install rigs to spin the wheels to do something similar for quick charging (instead of having to plug the car in)?
     
  6. JRP3

    JRP3 Hyperactive Member

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    Regen just uses the motor as a powerful generator putting out hundreds of amps, you could use something to spin the wheels and charge the pack, but it would be an inefficient system.
     
  7. markwj

    markwj Moderator, Asia Pacific

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    Figure I heard quoted was 20% (something like capturing 20% of the energy during regen).
     
  8. user497

    user497 Member

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    Yeah but aren't gas engines only 20% efficient as well? What I am thinking is you should plug at home and get your 80% efficiency off the grid but if you are going long distance you can stop and get just-as-efficient-as-gas quick charging via wheel rotation instead of plugging in. So you trade efficiency for speed in this particular case. This would just to be able to let people go long distances without range anxiety but people would still do 99% of their charging at home.
     
  9. vfx

    vfx Well-Known Member

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  10. Norbert

    Norbert TSLA will win

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  11. vfx

    vfx Well-Known Member

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  12. vfx

    vfx Well-Known Member

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  13. edo

    edo Member

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  14. JRP3

    JRP3 Hyperactive Member

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    Important study we can use to counter those who think there aren't enough resources to make EV batteries:
    Green Car Congress: Study finds resource constraints should not be a limiting factor for large-scale EV battery production

    I think we'll be ok for a while.
     
  15. TEG

    TEG TMC Moderator

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  16. dpeilow

    dpeilow Moderator

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