Solar-Powered High Efficiency Battery Charger


Posted on Feb 4, 2014

This is a simple NiCd battery charger powered by solar cells. A solar cell panel or an array of solar cells can charge a battery at more than 80 % efficiency provided the available voltage exceeds the fully charged` battery voltage by the drop across one diode, which is simply inserted between the solar cell array and the battery. Adding a step-do


Solar-Powered High Efficiency Battery Charger
Click here to download the full size of the above Circuit.

wn regulator enables a solar cell array to charge battery packs with various terminal voltages at optimum rates and with efficiencies approaching those of the regulator itself. However, the IC must then operate in an unorthodox fashion (a. k. a. Elektor mode`) regulating the flow of charge current in such a way that the solar array output voltage remains near the level required for peak power transfer. Here, the MAX639 regulates its input voltage instead of its output voltage as is more customary (but less interesting). The input voltage is supplied by twelve amorphous solar cells with a minimum surface area of 100 cm2. Returning to the circuit, potential divider R2/R3 disables the internal regulating loop by holding the V-FB (voltage feedback) terminal low, while divider R1/R2+R3 enables LBI (low battery input) to sense a decrease in the solar array output voltage. The resulting deviation from the solar cells` peak output power causes LBO (low battery output) to pull SHDN (shutdown) low and consequently disable the chip. LBI then senses a rising input voltage, LBO goes high and the pulsating control maintains maximum power transfer to the NiCd cells. Current limiting inside the MAX639 creates a ceiling` of 200mA for I out. Up to five NiCd cells may be connected in series to the charger output. When on` the regulator chip passes current from pin 6 to pin 5 through an internal switch representing a resistance of less than 1...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    USB Development Board
    TONE CONTROL AND SUBWOOFER OUT
    DVI to PAR digital video interface with LCD
    Pico ammeter
    SCR relaxation flasher
    lm723 variable power supply circuit design
    AVR ISP ScoketBoard
    Servo Driver
    Simple UHF Video Transmitter
    Simple preamplifier circuits by transistors
    Oscillators
    How To Build A Simple Code-Operated Switch
    Variable corner frequency tone circuit



    Top