Low-battery-warnlng-disconnector


Posted on Apr 24, 2012

NiCad batteries are excellent rechargeable power sources for portable equipment, but ~care must be taken to ensure that the batteries are not damaged by overdischarge. Specifically, a NiCad battery should not be discharged to the point where the polarity of the cell is reversed and is reverse-charged by the higher-capacity cells. This reverse charging will dramatically reduce the life of a NiCad battery. This circuit both prevents reverse charging and also gives a low-battery warning. A typical low-battery warning voltage is 1 V per cell.


Low-battery-warnlng-disconnector
Click here to download the full size of the above Circuit.

Since a NiCad, 9-V battery is ordinarily made up of six cells with a nominal voltage of 7.2 V, a low-battery warning of 6 V is appropriate, with a small hysteresis of 100 m V. To prevent overdischarge of a battery, the load should be disconnected when the battery voltage is 1 V x (N-ll, where N = number of cells. In this case, the low-battery load disconnect should occur at 5 V. Since the battery voltage will rise when the load is disconnected, 800 m V of hysteresis is used to prevent repeated on-off cycling.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Charger circuit V
    oscillator How to control a speaker
    Tone Generator Circuits
    Zero degree Celsius alarm
    rtc circuit
    LF356 composed of AD converter
    Electronic counter with automatic counting interface circuit a
    Emitter-coupled differential amplifier



    Top