NiCd 16,8V battery charger for drill

Discussion in 'The Projects Forum' started by acharis, Sep 7, 2013.

  1. acharis

    Thread Starter New Member

    Sep 7, 2013
    I have a problem. My old battery charger has been burned and I need to build new one. Battery is NiCD 16,8V 1300mAh. What I accept from charger?

    • Signalize turn on
    • Signalize, when battery is fully charge
    • Stop charging the battery after it is fully charge
    I have LM317 at home, so I design circuit based on it (see attachment). I know only basics of electronics, so I need to help to finalize my circuit.
    Can you help me?
    (Appologize my english :))
  2. doug08


    Jan 30, 2011
  3. DickCappels


    Aug 21, 2008
    Its a NiCd, not a gellcell, so trying the charger in the video on a NiCd would be somewhere between disappointing and lethal.

    The schematic you posted (LM317 as a voltage-limited current source) looks like a very good start. You will know when the charger is on from the glow of LED1 and you will know when its charging from the glow from LED2. When LED2 gets dim or goes out, the battery is nearly full charged.

    The amusing video at the link below is instructive and should give you an idea of why an indicator of when the battery is fully charged would be complicated task.
    Last edited: Sep 20, 2013