Basically what the title says
One 9V battery will give you somewhere between 120 and 200 hours of illumination with the simplest circuit, a series resistor. With a good switching voltage converter circuit you should be able to get more than 600 hours.
Select as Best AnswerUndo Best Answer
What sort of LED, which 9V battery? You could run quite a lot at low current with a good battery. L
If only for a short time a 9-volt can put out full amps at completely short circuit. Agreed - quite a few. As for how many - it would make a lot of sense to run series strings of 2-4 leds to better utilize the whole 9 volts and put THOSE in parallel with each other.
I've heard of that before, but I don't exactely understand how to do that?
Use http://led.linear1.org/led.wiz this calculator Each led has a forward voltage. 2 leds in series uses 2 times this voltage...etc. each led has a CURRENT. 2 leds in PARALLEL use 2 times this current. et al. 9 volts is way more than 1 led needs, and you'd need a resistor to burn off the excess. If oyu have 3 volt leds, you could put 3 in series and use a VERY small resistor to prevent overcurrenting the leds.
The link you gave me doesn't work =/ got any others?Okay! Thanks!!
always works! tell it 9 volts source 3 volt leds 20 miliamps each and total # of leds you wish.
http://led.linear1.org/led.wiz remove the &nsbp from the end.
Blue or red LEDs, and a Panasonic 9v.
red leds are 2-3 volts, blue are 3.5. Check the exact specifications on the packaging or model number.
Best answers can't be awarded on replies, but you've got it in theory... L
Awesome. Thanks everyone!