Super Fast Battery Charger?...

Discussion in 'General Electronics Chat' started by cjdelphi, Aug 17, 2011.

  1. cjdelphi

    Thread Starter New Member

    Mar 26, 2009
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    I'm talking about 1.2v AA/AAA cells. (Rechargeable and somewhat None Rechargables too)

    What's the limiting factor in charging? Would it not be fair to say Heat? put too much current through the cell causing it to heat up and explode? So would it be fair say if we could remove the heat then you could charge a battery a lot faster?

    How about a Peltier Device, have a couple of molded metal tubes connected to the Peltier Device, the molded metal tubes are connected to the Peltier device, the heat side get's a nice good heatsink, pop the A cells into the tubes, some kind of thermistor to monitor the temp of the battery cells, once it's sufficiently cooled down start pumping the current into the cells...

    Would this not work? Even charging none rechargeable cells at a lower current too I should imagine?
     
  2. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
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    Cooling and the addition of pulse charging may be the new trends, but experimentation is slow.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Primary cells, like alkaline, carbon-zinc, etc., cannot be recharged. Once discharged, they should be properly disposed of. If you attempt to charge a primary battery, you will likely cause the casing of the battery to rupture forcefully.

    Attempting to charge cells at a rate faster than recommended will result in increased internal power dissipation as heat, which will increase the chemical activity. While cooling the casing of the battery will help with the power dissipation, you may wind up causing thermal stress due to the differential in temperature from the middle of the package to the outer case.

    High temperatures are generally not good for batteries; it leads to increased chemical activity. The greater the chemical activity, the sooner the chemicals are depleted.
     
  4. wirednuts

    New Member

    Nov 13, 2011
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    0
    i think in non-rechargeable batteries, once depleted the chemistry inside has changed and can never be brought back. rechargeable batteries are formulated to stay stable through charges and discharges.
     
  5. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
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    NI-MH cells have an exothermic charge reaction which causes heating. NI-CD cells have an endothermic reaction which cools slightly during charging, until the cell reaches full charge and then it starts heating up.All cells build up internal gas which can blow out the vent when overcharged.

    The only way to safely fast charge them is to accurately detect full charge point, not a trivial task and NI-MH are particularly tricky.

    Don't even try fast charging lithium cells.
     
  6. t06afre

    AAC Fanatic!

    May 11, 2009
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    You can get some ICs that are tailored to charge NIMH batteries. Try Google and NIMH charger IC. Some of them even have a temprature sensor input. However for long battery life. Follow the battery manufacturer advice on charging current.
     
  7. sheldons

    Active Member

    Oct 26, 2011
    616
    101
    Heres a pcr charging circuit for aaa,aa,c and d type batterys(resistor values need to be changed for each battery type.....
     
  8. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    MAXIM used to make the best selection of those.
     
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