White LED project

Just a little something I whipped up and thought I'd share if anyone's interested...im thinking about putting the head into that laser barrel, using 3N cells to power it (possibly a resistor) and a push button. Its still kinda messy right now. What do you all think of my first project? 4 white LEDs overdriven to about 4v. Posting the pictures doesn't seem to be working here so i put them on a webpage~~> here

I'm all for experimenting - but your light seems awful close to a streamlight batonlight - 3N, 3LEDs (overdriven to 4V) - buton on the back and twist to lock on - While I LOVE to invent, I'd rather not re-invent a 29.95 wheel. Your time is valuable - take an M6 carcas from surefire and put 90 white LEDs in it. Now there's something that hasn't been done before [8^)

Just a thought

I think it would be a neat and affordable project. It may be hard getting everything to fit in there. Hmmwv, I like your idea too. But I`m not sure spending the money to do it would be a good idea right now. If the new LED we have be talking about on the other thread ends up being true, it might negate all the money spent (90 led`s could cost a bit)and one or two of the new led might be brighter and use less power too. I would build the one your working on, but hold off on spending a lot of money till we know one way or another on the other led, Just my one cent.

Looks nice. So what if it's been done before. If you've never done it, it's new to you.

At some point I'll probably pick up an iron and put something together and odds are it will be something simple. It's all part of the learning process.

Nightshift,

Cool project. It looks very bright.
I don't think you'll need a resistor though. I use 3 N cells in some of my lights with only one white 5600mcd LED and never had a blowout yet. My AA Maglight with 3 N cells, no resistor and one LED draws around 60mA on my meter. It never seems to get hot.
The N cell is rated at 1000 mAh. I'm still on my first set in my Maglight. They last a long time.
Here is some good battery info: http://data.energizer.com/batteryinfo/product_offerings/alkaline/energizer/alkaline_consumeroem.htm

Brad,
Thanx for that last post.
thebatteryman here is always
hungry for more info.

Is 4 volts really overdriving an LED? 3 alkaline batteries add up to 4.5V and are routinely used by manufactureers with no resistor. 2V would give you a light that puts out about as much light as a Coleman keychain lantern you can get at Home Depot for 2 bucks. I think the voltage ratings on the LEDs are really conservative, but I don't know the technical reasons.

In lights with 4.5 volts worth of batteries, the LED is almost certainly not getting 4.5 volts, probably not even near 4v for AA/AAA types. The reason is that the current drawn by the LED when overdriven gets too much for the batteries to supply their full voltage- this is to do with internal resistance of the cells. Small batts have a higher internal resistance so can put out less current. For example in the Photon-II there are 2x 3 volt batteries= 6 volts but since they are such small capacity, when the LED is turned on the voltage drops a lot, to maybe under 4v. A similar thing happens in, for example, one of Brad`s conversions with 6 or even 12 volt batteries- the voltage drops considerably because the LED tries to pull more current than the battery can deliver. If you hooked an LED to a large regulated variable voltage power supply (I`ve got one here that will hold its set voltage rock steady for up to 5 amps current draw) and cranked it up, your LED would go all black and stinky before you hit 4.5v. With batteries however you`re normally safe overdriving an LED, except where you might use high capacity batteries- 3 D cells would probably cook a lone white led with no resistor whereas 3 AAs wouldn`t. It`s the current draw you have to watch for- the voltage essentially looks after itsself so I`ve found.

In my experience, 4.5v.input will never over drive a white, super green,aqua, or blue, but it certainlyWILL on the other color LEDs (with no resistor)
When I experiment without the ma
meter, I always look for the 1st
WARNING sign-a noticable dimming
of the led after 5-10sec.or so..
(plus the HEAT)

I wasn't really trying too hard to make a flashlight...just something to hold them all together so i could show em off or use them without them falling all apart or shorting out. Didnt really cost me anything...just some spare parts lying around...we have about a foot of snow out there by now and still going...nothing better to do with my time right now

So overdriving LEDs doesnt make them burn out instantly? I am afraid to over drive them to say..2 volts or more. Once way back when, i remember hooking up a dull red LED to a little more voltage and i think it turned an ugly orange and blew. How high can you safely overdrive a 3.6 rated LED? I think i've read people going up to 12 volts?