6 12V emergency light using power LED

Another emergency light circuit that is very easy to construct and uses power LED not an array of LEDs unlike the simple led emergency light. The circuit is composed of two parts, the charger and the led driver. When the battery voltage is higher than the voltage of zener diode DZ + 0.7V, the charger automatically turns off (protect the battery from overvoltage).  Transistor Q4, R6, D1, D2 is the led driver circuit (See cheap led driver to know more how this circuit works).

schematic diagram

Part List:

R1 - 560 ohms 1/2W

R2 - 220 ohms 1/4W

R3 - 1 kilo ohms 1/4W

R4 - 10 kilo ohms 1/4W

R5 - 500 ohms 1/4W

R6 - value is dependent on LED power, see notes below

Q1, Q4 - TIP41C, or similar NPN Power Transistor

Q2 - 2N2222, CS9013, or similar NPN transistor

Q3 - CS9012, 2N4403 or similar PNP transistor

Dz - 12V zener diode minimum 1/2W rating

D1, D2 - 1N4001, or similar diode

Bat - 12V lead acid battery

LED - 3W white power LED

DC input - see  AC-DC converter circuit below

DC Input Supply

schematic diagram of AC-DC converter

Part List:
Transformer - 220V to 12V center tap transformer rated 10VA
D - 1N4004 or similar silicon diode
C - 1000uF electrolytic capacitor rated 25V

Value of R6
Resistor R6 will limit or control the current of the LED. The basic idea is we need to know the rated forward current for the LED. After that, we can use the formula below to determine the value of R2.
R2 = 0.8 / Current and power of R2 = Current*Current*R2
Example: 3W LED has the current rating of 530mA
               R2 = 0.8/0.530 = 1.5 ohms
               Power Rating = 0.8*0.8*1.5 = 0.96W or 1W

Parts Diagram and Pinout: click image to enlarge

TIP41C pin

2N2222, CS9013 pin

CS9012, 2N4403 pins

LED pins

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Updates:
Modification below allows you to know if the battery is fully charged. When LED1 is off and circuit is connected to AC, it means the battery is charging . When battery is on, it means the battery is fully charged.

full-charge indicator

Part list Modification: (Other parts same as above)
R3 - 390 ohms 1/4W
Dz - 1N5240B or any 10V zener
LED1 - red LED or any LED with forward voltage around 2V (see LED info to know more)