5.7v/400mA from just 1.5v AA BATTERY !!!

Discussion in 'General Electronics Chat' started by mkbutan, May 11, 2011.

  1. mkbutan

    Thread Starter Senior Member

    Sep 30, 2008
    270
    16
    Any circuit which deliver the voltage & current for the Mobile Battery (4.5v) charging with just one AA type (1.2v/1.5v) Battery?
    Specification:
    Maximum Current:400mA
    Output Voltage:5.7V+5%
    Power source 1 X AA Battery.

    Suits to charge Mobile phone, digital camera, PDA, MP3, MP4, etc.

    This Blue Emergency Battery Charger for Mobile Phone is been soled by the e-bay
    ( http://cgi.ebay.com/Blue-Emergency-...117129?pt=PDA_Accessories&hash=item3f0133e249 )

    I don't think so it can deliver 5.7v/400mA with just one 1.2v 0r 1.5v AA battery!!!!!!!!!!
     
  2. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    An Alkaline AA cell has about 2.6wh of energy.
    5.7v @ 400ma is 2.3w.
    2.6wh/2.3w = 1 hour and 8 minutes of life @ 100% conversion efficiency.
    At a more realistic 85%, you'll get 58 minutes.
     
    mkbutan likes this.
  3. mkbutan

    Thread Starter Senior Member

    Sep 30, 2008
    270
    16

    But AA/AAA Battery is about 1.5v
    then how it can charge 4.5v Mobile battery?
    pl. explain with any CKT.
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    By means of a boost converter. http://en.wikipedia.org/wiki/Boost_converter

    There is nothing very special about these gadgets, but note that you won't get much of a charge out of a single AA cell. In an emergency though, with no access to power I suppose you might be able to charge a phone enough to make a call or two.
     
  5. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    The efficiency is dismal at best, though it is possible to do

    Witness the disposable [ film ] camera, that employs a single AA battery to power its flash, which charges a capacitor up to a 200μf - 350 Volts dc to run the flash.
    They recycle to be able to fire in roughly 30 seconds, not to mention the battery is still marginally useable after the film is all exposed...........

    You will have to do your own research based on your electronic experience ?? to find and comprehend the necessary circuitry, because know this............those little camera circuits are downright deadly if handled improperly.
     
    Last edited: May 21, 2011
  6. mkbutan

    Thread Starter Senior Member

    Sep 30, 2008
    270
    16

    Flash camera's have the LCR CKT. to boost and store the energy for the capacitor to charge for the film Camera but not in mobile
     
  7. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    The camera is but one example that a single AA cell can be used for larger applications.

    You will have to do your own research based on your obviously limited electronic experience ?? :D to find and comprehend the necessary circuitry, because know this............those little camera circuits are downright deadly if handled improperly.
     
  8. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    The "emergency" chargers normally use a fly-back principle, typically using a little ferrite bobbin choke just a few millimetres long. Similar things are seen in little torches (flashlights) that run white LEDs off just one alkaline cell.
     
  9. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    PackratKing likes this.
  10. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Solar garden lights use a simple and cheap voltage stepup circuit to use a single 1.2V rechargeable battery cell to light a 3.5V white or multi-colours LED all night long.
    A solar garden light is on sale this week for only $.99.
     
  11. nbw

    Member

    May 8, 2011
    36
    10
    I found a webpage (might have been an Instructable?) that showed how to make a stun gun out of a disposable camera - using that same HV cap you mention. So yes - be <snip> careful!
     
    Last edited by a moderator: May 22, 2011
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