Zener diode charger

Discussion in 'The Projects Forum' started by MMH, Feb 26, 2013.

  1. MMH

    Thread Starter Member

    Feb 8, 2013
    143
    4
    Hello there everybody!! I have a manual charger to charge my nimhs. According to my DMM, the voltage starts decreasing at 1.825v. I therefore have bought a 1.8v zener diode to put across the battery in reverse while charging, so that I am able to understand when it is fully charged. Will it work? I will connect an led at the end of the diode. Will the diode act as a small load for the batt? Plz help.
    Thank you!!
     
    Last edited: Feb 27, 2013
  2. crutschow

    Expert

    Mar 14, 2008
    12,995
    3,229
    Depending upon its color the LED with have 2-3V drop which adds to the zener voltage, so the LED won't light until over 3.8V.

    A single NiMH cell charges to about 1.6V maximum. Where did you get 1.825V?

    Note that you can't determine when a NiMH battery is charged from its voltage.
     
  3. MMH

    Thread Starter Member

    Feb 8, 2013
    143
    4
    I got that reading from My multimeter. If thats the case then I will not use led. I will use other kinds if indicator like DMM to measure voltage. Will it work-if I am sure that it is 1.825v-when the voltage starts decreasing.
     
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