Project for batch-6:solar charger

Solar charger for 6v battery:

This is a solar charger based on LM317 regulator IC. The charger is similar to the 6V charger project but made simpler. When battery has reached is full charge voltage (Bat voltage is higher than VDz + 0.7), the charger automatically cuts the charging to protect the battery form damage. The led light will indicate the full charge state in the battery. This charger will work only when the voltage from the solar panel is much higher than the battery voltage, unlike the solar charger with regulator and controller that can charge regardless the solar voltage.

Part List:
Solar - 12V solar cells array
C1 - 470uF electrolytic capacitor rated 25V
D1, D2 - 1N5400 or any rectifier diode rated 2A minimum
Dz - 1N5235B or any 6.8V zener diode
R1 - 3 kilo ohms 1/4W
R2 - 330 ohms 1/4W
R3 - 560 ohms 1/4W
R4 - 2 kilo ohms 1/4W
LED -3mm or 5mm  Red or any low power LED
Q1 - 2N2222, CS9013, or similar NPN transistor
Bat - 6V lead acid battery

Note: You can convert the charger into 12V by replacing the solar panel with higher voltage ; zener diode DZ; and values of R2 and R1.
Read more at http://www.simple-electronics.com/2011/10/solar-charger-for-6v-battery.html#LmUU97tQ5pjYtlET.99