Is This Possible.

Discussion in 'The Projects Forum' started by MrMaxwell, May 28, 2011.

  1. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    I'm currently working on a Summer project for my degree (I'm just two semesters in). I only have 10 days to decide all of which parts needs to be ordered. The money that will be used to purchase the parts is not mine -- it is my professors. So I really don't want to "F" up -- get it?

    The question: What would be the best way to convert short lived 1/4v to 6v AC currents, so that they can be stored on a commercial rechargeable battery pack?

    http://www.harborfreight.com/person...pack-67728.html

    I'm attempting to store the small AC currents made from a simple shake-generator (http://www.creative-science.org.uk/gensimple1.html) onto the device above, or onto something similar.

    I've been looking into converters, rectifiers, and other smiler devices, but I'm still a bit confused. Google has helped me to generate a bit of understanding of what I'm looking for. The 100v-110v input minimum that I suspect the magnum-rechargeable-pack's wall adapter to have is the key factor for my lack of confidence for the part ordering.

    Can anyone help me?
     
  2. #12

    Expert

    Nov 30, 2010
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    Your first link didn't work for me...404 Page not found.

    Anyway, a low voltage rectifier seems to be needed. They are called Shottky. AC must be rectified to put it into a battery, and tiny little volts have trouble getting through rectifiers, but the Shottky diodes have low voltage requirements at low currents.
     
  3. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    http://www.harborfreight.com/personal-electronics-portable-charging-pack-67728.html

    I'm trying to store power/charge this rechargeable pack with small, short lasting AC currents from a shake-generator.

    Are you saying that I basically need to place the Shottky before the female power plugin adaptor, then plug the rechargeable packs adapter into the female power adaptor, and problem solved?
     
  4. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    I've been looking at this rectifier.

    http://www.virtualvillage.com/Items/007901-023
     
  5. BillB3857

    Senior Member

    Feb 28, 2009
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    Get one of the shaker powered flashlights and do an autopsy on it. In technical circles that is called "reverse engineering"!
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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  7. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    I'm trying to use the shake light to charge a rechargeable battery pack. The battery pack is 3.9v and also has spec a of 3000maH. The shake light will put out a AC current after I gut it. Is it possible to slowly charge the battery pack with the small and inconsistent AC currents generated?
     
  8. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    Okay. I believe that if I cut off the battery packs original adaptor, and then connect the battery packs power cord to the linked circuit, then it should work. Do you agree?
     
  9. CDRIVE

    Senior Member

    Jul 1, 2008
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    Did you read these specs from the HF link? You'll be shaking that thing until your wrist falls off!

    • Seven accessory adapters for Samsung, Motorola, Nokia and Sony-Ericsson
    • Retractable USB cable
    • Pack recharges in 3-1/2 hours
    • Charges most cell phones within 2-1/2 hours
    3.9 volts3000 mAh
     
  10. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    But will it work? I'm hoping that the current would be able to pass through the pack and charge a mobile device? I know this technology is out.
     
  11. BillB3857

    Senior Member

    Feb 28, 2009
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    Google is your friend... http://express.howstuffworks.com/autopsy-shaker-flashlight.htm
     
  12. Adjuster

    Well-Known Member

    Dec 26, 2010
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    I think that you should able to get some charging effect out of this, but you may need to use a boost voltage converter to increase the output voltage from the generator. I am quite certain though that a full charge would take an impracticably long time.

    The battery pack you mention might need about 18 watt-hours of input to recharge it fully (the exact amount depends on its efficiency), but it would surprise me if you got more than a small fraction of a watt out of that shake generator. A full charge would thus take days of continuous effort, and most likely the user would be suffering from a bad case of RSI before then!
     
  13. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    If the device outputs a HIGHER voltage than the battery pack then it WILL charge the battery.

    Be sure you have a diode in the charge output line to prevent the battery from discharging through the charger during the period when voltage is lower than the battery voltage.

    Simple pimple. Now you just have to convince someone to shake the thing for several days to get a battery charged.
     
  14. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    I think if you could find a magnet lets say size of a C battery, then you could use some some springs on each side to make the magnet resonate at some reasonable frequency, which could help with efficiency. Of course the bigger size of the magnet will help too.

    ETA: For example a magnet like this: http://www.amazingmagnets.com/show-fractional-r1000f.aspx and a proper coil could make some significant output. Watch out as it is a very powerful magnet and you will have trouble getting it off metal surfaces.
     
    Last edited: May 29, 2011
  15. CDRIVE

    Senior Member

    Jul 1, 2008
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    IMO, this is the only 'practical' circuit for a shaker generator. Charging a battery.....???? .... Not so much! ;)

    Edit: BTW, shouldn't there be a limiting resistor? A large cap can pump out quite a bit of current.
     
  16. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    I've decided to make the flashlight big enough to accommodate four of the same size batteries (Ceramic grade 5 though). I now believe that a diode will allow me to charge the pack by cutting off the adaptor of the battery pack. Also, I'm attempting to make the generator with 2awg magnetic wire.
     
  17. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Ideally you should have large enough voltage to allow simple rectification and conversion to feed the battery.
     
  18. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    Are you referring to my last post with this statement?
     
  19. Kingsparks

    Member

    May 17, 2011
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    How many turns do you plan for the generator?
     
  20. MrMaxwell

    Thread Starter New Member

    May 28, 2011
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    1200 or more. I'm ordering 500ft of 22awm magnetic wire.
     
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