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Discussion in 'General Electronics Discussion' started by [email protected], Mar 26, 2012.

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  1. smhn72@gmail.com

    [email protected]

    24
    0
    Mar 26, 2012
    i want to make a rechargable fan
    i hav a battry of 12 v 7ah
    but the charging time of this battry is so much
    i want to reduce the time
    how it is possible
    i m charging it with a 12 v dc supply
     
    Last edited: Mar 26, 2012
  2. GreenGiant

    GreenGiant

    842
    6
    Feb 9, 2012
    You need to increase the current that the supply outputs to the cell when it is charging
    for example if you are supplying the battery with 7 Amps it will theoretically fully charge in 1 hour, give or take a few minutes.

    Doubling that to 14 will reduce the time to charge down to 30 minutes give or take

    the only other thing you would need to do is slowly taper off the current once it is fully charged, this will ensure it is charged to its fullest

    This is all assuming that the circuitry can handle the currents that were mentioned
     
  3. smhn72@gmail.com

    [email protected]

    24
    0
    Mar 26, 2012
    Sir thanks u so much
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    11,702
    2,717
    Nov 17, 2011
    When charging the battery don't forget to observe the characteristic of the battery: different battery chemistries need different charging strategies. This is why there are quite a few charger ICs on the market.
    Further: also GreenGiant is right in stating that twice the charging current approximately halves the charging time, You cannot increase the charging current at will. Every battery has an upper limit for the charging current. If you force too high a current into the battery it will degrade faster than normal. It may even blow up. You should find the necessary information in the battery's data sheet. If you do not have one, look in a few data sheets of similar batteries and figure out a useful compromise.

    Harald
     
  5. smhn72@gmail.com

    [email protected]

    24
    0
    Mar 26, 2012
    thanks u sir
     
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