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Single Blinking LED Battery longevity. Which is best, (2) AA or 9 volt? Answered

Want to know what is the best method to power a single Blinking White 5mm LED and get the most battery life. How long and what type battery could keep it going continuously the longest?

Tags:LED

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2 AA i have made fake alarm lights doing this

the AAs

my estimation. i dont know the real AH of batteries (and its different with every manufacturer). i estimate based on experience and the volume of the AAAA batteries inside the 9V (volume and capacity roughly go together)

1 AA = 1.5 V 4 AH = 6 WH
2 AA = 12 WH
9V = 9 V 0.5 AH = 4.5 WH

you may need to do hacks to get the white led going bright on 2.3 V (3 V less the 0.7 V on the transistor that makes it blink) or 3 V (if you use a mosfet). those hacks lower the efficiency but i think still the AAs are way better

to get max life use PWM (with N555 chip) instead of resistor. use a mosfet to drive the led. in the blinking make it like flashes - short time on and long time off