I want to be building a high powered flashlight with LEDs. It's required to have a LED driver and or resistor?

Question

So I wanted to build a high powered 200 lumens flashlight with an LED. It's 3.2V~3.3V. I was wanting to know if I could hook up a pair of AA batteries in sequence along with a switch to the LED and use it like that. It would give me a 3 volts. Or should I be using a 9 volt battery and a resistor (Which is fuzzy for me) and switch with the led plate? Fist time for me and I'd like a bit of help thanks!

Anonymous · Accepted Answer

a) 200 Lumens isn't high-powered, it's mediocre (at best), considering current LEDs
b) a pair of AA batteries won't give you three volts - at least not for long, considering that you'll need around 700 mA going through the LED. But even if - 3.0 Volts is not 3.4 Volts. The usual ways for this are
1) use three AA or AAA cells in series, possibly with a small series resistor. Rechargeables are preferred to primary cells
2) use a single Li primary cell. In either case, you'll need to figure in the internal resistance of your batterie(s) in order to limit the current through the LED, and you'll get a horrible performance since your light output will be (hughly) dependent on the runtime, i.e. the longer you run the light, the dimmer it gets.
3) use any reasonable (i.e. don't mix Li and NiMH) combination of cells you like and a matching current regulated step-up (or -down) converter to drive the LED.

jimmy · Answer

You need a power transistor to drive several LEDs housed at a concave mirror to create a beam.......you probably need 12 V......

Learn-How-To-Weld.com · Answer

My FENIX TK40 is high powered at 640 Lumens,  you should check it out here http://www.superbrightledflashlight.org/

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I want to be building a high powered flashlight with LEDs. It's required to have a LED driver and or resistor?

3 Answers