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Domain: powerstream.com

Stories and comments across the archive that link to powerstream.com.

Comments · 53

  1. Re:NEVs? by rcw-home · · Score: 4, Informative · on Washington State Legalizes NEVs on Public Roads
    Oh, and don't forget that according to the 2nd law of thermodynamics, you've lost energy at every step in that process, so you are probably not as efficient as a good gasoline engine

    Assume a power plant is 80% efficient. Assume electricity distribution is 95% efficient. Assume lead-acid columetric efficiency is 70%. Assume larger electric motors are 90% efficient.

    .80*.95*.70*.90 = ~.48

    Your total efficiency still exceeds the brake efficiency of most car engines by several percentage points. Also, car engines lose energy at the clutch and transmission, must waste energy while idling, and cannot recoup energy from braking.

    The assumptions above are from quick google searches - if you have better/conflicting info, let me know.

  2. Re:how to maximize battery life? by Red+Rose · · Score: 1 · on 10.2.4 Killing Battery Life

    Afaik that is bullshit, i've read (some years ago) on various manufacturer's pages that lion batteries like being full.

    Best reference i can provide is: http://www.powerstream.com/li.htm, they say a safety mechnism for overdischarge of lion batteries should implemented: "stops discharge when battery voltage falls below 2.3 volts per cell"

    From my own experience, it's just about carma.

    So keep 'em full.
    --
    Ain't got an Apple, yet.

  3. Re:Gahhh by modecx · · Score: 1 · on Laptop Fuel Cells Approved For Air Carriage

    Battery size chart here. Apparently A size batteries are 17mm in diameter by 50mm. They have a slightly larger diameter than AA (at 14.3mm). I don't think I have seen one--ever.