Looks like a Joule Thief for AA cells

Discussion in 'General Electronics Chat' started by John P, Jun 2, 2015.

  1. John P

    Thread Starter AAC Fanatic!

    Oct 14, 2008
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    I just saw an article about a gizmo soon to be launched, called the "Batteriser". They claim that it boosts life by a factor of 8, which sounds like an exaggeration, but it still might be a reasonable idea. What it does is suck energy out of the battery until the voltage drops below some very low level--0.6V I think. I could imagine using these things in a camera I have, which runs until the battery isn't "empty" but is instead "not quite full" and then demands a replacement. Sometimes I use the batteries again in something else.

    http://www.pcworld.com/article/2928...by-800-percent.html?google_editors_picks=true

    I'd be interested to hear how much energy an alkaline AA cell supplies from brand-new until (let's say) the voltage output is down to 1.2V, versus the amount that it could supply between 1.2V and 0.6V. That's the key issue--assuming power output is constant, how much more energy can you get if you keep pulling current as the voltage drops?
     
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  2. ian field

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    Oct 27, 2012
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    At the advertised price - its probably worth giving it a try.

    It might be just the thing to be able to run a desk clock on a nickel chemistry cell, they usually complain about the lower terminal voltage only a week after charging.

    The gadget probably has higher apparent internal resistance, so might not do so well on high drain applications. Boosting the voltage increases current draw from the cell, so a failing cell will collapse even quicker.
     
  3. wayneh

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    Sep 9, 2010
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    I don't think there's much juice left, percentage-wise, when the voltage starts to fall off the shoulder. That means the chemicals are nearly spent and/or the diffusion barrier is causing excessive internal resistance. Still, I do like throwing out a cell that is fully dead. I can't bring myself to toss cells that still have a slight charge left.

    I don't think this will solve the camera battery problem. My wife's Canon was super annoying in that regard. If the batteries weren't brand new, the camera would complain to my wife and you can imagine how quickly that would roll downhill to me.
     
  4. MikeML

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    Last edited: Jun 3, 2015
  5. wayneh

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  6. MikeML

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    Try it now...
     
  7. MikeML

    AAC Fanatic!

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    Try it now...
     
  8. ErnieM

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    Right now?

    (I think we can call this one "BUSTED.")
     
  9. cmartinez

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    If something seems to be too good to be true... it probably is...
    I've never heard the "mouse milk" phrase before....
     
  10. wayneh

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    Sep 9, 2010
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    The curves posted at that link were exactly what I was visualizing. At the shoulder, you're nearly done.

    The only way the Batteriser might be useful, in my estimation, is not in a flashlight but in a device like my wife's Canon camera (since replaced) that is very picky about voltage.

    For instance look at those curves and imagine a device that gives up when voltage falls to 1.1V. That's far before the shoulder and there's quite a bit of juice still remaining, but the picky device stops working. This was exacerbated by using rechargeable cells, since their nominal voltage is already lower. A lot of juice was left when the camera rejected them.

    If the Batteriser can solve that problem by allowing a cell at 1V to power a device requiring ≥ 1.3V, it might be worth it.
     
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