solar charger

Discussion in 'The Projects Forum' started by jkdelz, Jun 24, 2011.

  1. jkdelz

    Thread Starter New Member

    Jun 24, 2011
    Here is a solar charger circuit that is used to charge Lead Acid or Ni-Cd batteries using the solar energy power. The circuit harvests solar energy to charge a 6 volt 4.5 Ah rechargeable battery for various applications. The charger has Voltage and Current regulation and Over voltage cut off facilities.

    The circuit uses a 12 volt solar panel and a variable voltage regulator IC LM 317. The solar panel consists of solar cells each rated at 1.2 volts. 12 volt DC is available from the panel to charge the battery. Charging current passes through D1 to the voltage regulator IC LM 317. By adjusting its Adjust pin, output voltage and current can be regulated. VR is placed between the adjust pin and ground to provide an output voltage of 9 volts to the battery. Resistor R3 Restrict the charging current and diode D2 prevents discharge of current from the battery. Transistor T1 and Zener diode ZD act as a cut off switch when the battery is full. Normally T1 is off and battery gets charging current.
    When the terminal voltage of the battery rises above 6.8 volts, Zener conducts and provides base current to T1. It then turns on grounding the output of LM 317 to stop charging.


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    Last edited by a moderator: Jun 24, 2011
  2. Wendy


    Mar 24, 2008
    Welcome to AAC.

    This thread is quite old, the original poster (OP) is long gone. Nice try though.
  3. bertus


    Apr 5, 2008

    You just hijacked an old thread:
    Combining 3 renewable energy sources

    Now you have a thread of your own.


    Please do NOT post any commercial links.
    A second time will result on a ban.
  4. wayneh


    Sep 9, 2010
    What is the function of D1 and the LM317? Both just burn off power and don't really contribute. The zener and the transistor are doing all the control. Resistor R3 also just wastes power.