Home Built LED Flashlight BULBS

I was looking at putting together 3 white LEDS into a standard Flashlight pumping 4D cells (6.0 volts).
I figure that I should solder the bulbs in series. Anybody got an idea what size resistor I should hook into this project?
How about for 2 LEDS and everything else being equal?

I think this forum is going to rock in time.
Too many of us light freaks out there.

My wife gets a kick out of counting all the flashlights that I have lying around just my computer desk (about 12 right now if you count the 2 lasers).........

You can hook them in series, but I reccomend against it, if one goes out they all do, and as they warm up their current draw will change too.

For parallel hookup the ohm calculation works out this way,
(voltage source - LED voltage )/ LED current. White LED's are usually rated at 20 ma, but some products their driven at 50 ma, so lets set the LED current at 30 ma.

So substituting in, (6 - 1.7)/.03 = 143 ohms more or less. You can probably get 150 ohm resisters at radio shack in a pack of 6 for $1.

DaveH

[This message has been edited by DaveH (edited 08-22-2000).]

I would suggest 3 leds in paralled and then using 3 cells. Most white led's want about 4vdc. Wiring 3 in series and using 4 cells wouldn't probably not even light. A couple of places sell a 3 led replacement PR base lamp for 3 cell lights.

Brock

Here's a webpage I bookmarked a while back:

http://members.xoom.com/aa0ni/flashlig.htm

I exchanged a couple of emails with Daniel and was going to have him make a white 3 LED bulb for me, using a screw base. I never purchased a Petzl headlamp so never had the bulb made. But now you can buy 3 white LED screw base bulbs just as easily as those using the PR base LED Bulbs. Try www.ndsproducts.com or www.theledlight.com

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"A knifeless man is a lifeless man"
-Nordic proverb

Another thought; the white Photonlight runs at 6V. Ask at their forum for a source of white LED's.

Brian Avery at one time said you can buy bare LED's from LRI. If you do use these, I recommend parallel wiring.

------------------
"A knifeless man is a lifeless man"
-Nordic proverb

[This message has been edited by DavidW (edited 08-22-2000).]

Just a note here, photon's lights may be limited in that the batteries can't produce enough current to harm the LED at 6 volts.
I think what happens is once the batteries see the "load" of the LED the working voltage drops as well.

A "D" cell would be able to provide much higher currents, and at the same voltage fry an LED.

DaveH

[This message has been edited by DaveH (edited 08-22-2000).]

The LED's that Photons use are the 5600 20 degree Nichia's. When they are running on the 2 2016's (used in the photons) they are at about 4.6v on a new set of batteries. So there is quite a voltage drop because of the cell size. When you use even 3 AA cells in the lightwave the voltage drops from about 4.8v no load to 4.7 with the light on.

I would also suggest just buying a PR or mini screw-in base. They tend to use the brighter 5600 Nichia's that aren't as easy to get a hold of in small quantities.

Brock

[This message has been edited by Brock (edited 08-23-2000).]