9 Volt 250mAh Ni-MH rechargable battery charger

Discussion in 'The Projects Forum' started by RodneyB, Sep 21, 2014.

  1. RodneyB

    Thread Starter Well-Known Member

    Apr 28, 2012
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    16
    I am trying to make a charger for my 9 volt rechargeable Battery.

    I was wondering if the attached circuit is suitable.
     
  2. bertus

    Administrator

    Apr 5, 2008
    19,411
    3,926
    Hello,

    No, there is no current limitation.
    Without any current limitation you could overheat the battery.

    Bertus
     
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  3. bertus

    Administrator

    Apr 5, 2008
    19,411
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    Bernard and RodneyB like this.
  4. RodneyB

    Thread Starter Well-Known Member

    Apr 28, 2012
    697
    16
    Thank you for all the advice and assistance

    Best wishes

    Rodney
     
  5. jjw

    Active Member

    Dec 24, 2013
    364
    37
    9V battery is usually made of 7 cells and it's voltage after full charge can be ~ 10.5V.
    12V supply voltage is probably too low because LM317 needs even with small currents at least 1.5V differential between in and out terminals + 1.25V over the current limiting resistor.
    15V supply should be enough.
    It is recommend to charge the battery 12h at 10% current, because the charging efficiency is not 100%.
     
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  6. upopads2

    Member

    Sep 20, 2014
    52
    1
    This is a great circuit thanks for sharing.
     
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