UNIVERSAL BATTERY CHARGER


Posted on Feb 4, 2014

This is a charger circuit for both NiCd and NiMh Batteries. Some time ago I aquired an old commercial handheld-TRX which was powered by a 12 Volt NiCd-Battery pack (10 Button Cells each having a capacity of 280mAh). In fact this (at least 10 year) old battery is best because there is a very special charger used: When the Battery voltage is low it


UNIVERSAL BATTERY CHARGER
Click here to download the full size of the above Circuit.

is charged with the usual constant current source in the normal way. But when the battery voltage increases, the charging current will become pulsed. A completly fully charged battery only requires short flashes to maintain its charge and terminal voltage. Here is the circuit diagram: The original circuit used some old-fashioned components, so I devised a completly new design using only standard, commonly available components. The LED (green) shows that the battery is charged. A full battery is indicated when the LED is "dark" most of the time. Set the Charger to 1. 42 Volts for each cell (i. e. 5. 68V for a 4. 8V Battery-Pack) by adjusting the 47k variable resistor. The charging current is around 120mA and can be changed by adjusting the 12 Ohm resistor, or the forward votlage (colour) of the LED. At the moment I am using the new circuit for 4. 8V, 6V and 7. 2V Batteries having a capacity ranging from 500mAh to 1200mAh. 12vDC is used to power this charger. Here is a photograph of the completed project:




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Electronic ship siren
    Power meter 1KW
    Arduino Calibration
    Mini High-Voltage Generator
    Simple condenser microphone circuit Schematic Diagram
    Cipher scheme of the module of infrared remote-control between two parties of intellectual family
    5000 watts power inverter
    Combining the Composite Sync to the Green Signal
    Yaesu G-400 Antenna Rotator Controller
    Sampling RF Power
    Reflected light intensity detecting circuit CD4052B CD4011B



    Top