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Here is a video of a mod to a cheapo flashlight that can make it real bright. "Brighter than a Surefire" is what the dude says. Looks pretty cool to me. If anyone tries it, post your results. LINK

looks like i know what ill be doing tomorrow at work! a trip to wally world and radioshack first!.

Of course it's really bright! He's powering a 6v 750mA Krypton bulb with three 3v Lithiums - ie 9 volts. I'm guessing he won't get too much longevity out of either the batteries or bulb, but if he's just using it as a toy "cop flashlight" to temporarily blind himself and others... more power to him.

Having said that, it's good to see innovation at work. Thanks for the link, Scott. I've been wondering what to do with those cheap Eveready lights I have...


P.S. Don't those Duracell Ultra CR123 Lithiums sell for around $4 each - not $4 for three of them? That would make it a $15-20 flashlight, still cheaper than a Surefire though.

NZcaver wrote:Of course it's really bright! He's powering a 6v 750mA Krypton bulb with three 3v Lithiums - ie 9 volts. I'm guessing he won't get too much longevity out of either the batteries or bulb, but if he's just using it as a toy "cop flashlight" to temporarily blind himself and others... more power to him.

I'd bet that if the light was left on long enough in the right conditions, it would burst into flames.

P.S. Don't those Duracell Ultra CR123 Lithiums sell for around $4 each - not $4 for three of them? That would make it a $15-20 flashlight, still cheaper than a Surefire though.

I've seen them much cheaper than that on some website (?). Something like a dozen for $20.

i blew a 1 watt luxuon led today at work, had it wired to a 5 volt voltage regulator, then to a 18v dewalt battery, didnt have a big enough heat sink, burnt the regulater and the led took 18 volts straight, turned a little blue then died

leedy if that was a typical 5v regulator then it was putting out about 650ma too much current. I would imagine it didn't take long to fry. Those one watters generally run at about 350ma not the 1amp the 5 watt regulator typically supplies. Heh heh better throw some resistors or another 1 or 2 leds in there next time

yeah i learned my lesson this time, didnt take long to go at all realms, haha

Amperage regulation is MUCH more important than voltage regulation when it comes to LED's.

yeah, i had the led, and regulater wired originally to a 9 volt battery heatsink would barely get warm, 5v regulator said it could take anything up to 36v and knock it down. so then i wired it to the 18v heat sink got HOT fast!!

50 lithium CR123s for $48.50 (not Duracell, though).

erebus wrote:50 lithium CR123s for $48.50 (not Duracell, though).

Not bad! So $4 for three Duracells just *might* be possible.

At the other end of the price spectrum, REI stocks genuine Duracells at $12.95 for a 2-pack.
http://www.rei.com/product/715031

Personally, I'd rather use something that runs AAs even if the flashlight guy thinks they "just don't have enough juice".

KPR112 bulbs as in the video seem to have been used in mods before, but lifetime is definitely uncertain.
http://www.candlepowerforums.com/vb/sho ... hp?t=73615
http://www.candlepowerforums.com/vb/sho ... nextoldest

adleedy wrote:yeah, i had the led, and regulater wired originally to a 9 volt battery heatsink would barely get warm, 5v regulator said it could take anything up to 36v and knock it down. so then i wired it to the 18v heat sink got HOT fast!!

The 9 Volt transistor battery can not put out much amperage to begin with while the 18 Volt battery was feeding a full amp to the led easily. The led went into thermal run away...as it got hotter its resistance dropped allowing it to pull even more current...

With the LED and the 7805, it's not really the case that a 7805 will automatically current-limit at an amp, it's more that it's a 5V regulator only *rated* at an amp for general usage. Looking at a 7805 datasheet, when cold, it's possible to get 2-3A through one, and even when it's fully warmed up, 1.5-2A seems quite possible, at least for that particular flavour of 7805.

A 5V supply with a capacity to give 2A+ might well push 2A through a Luxeon I, and that could pretty rapidly prove terminal even if the regulator didn't fail.

lol thats pretty much the conclusion we came to. He burned the LED up. The 1 amp that the regulator provided was way over the limit as mentioned earlier in the thread. The reason it didn't fry right way on the 9 volt is the fact that they typically put out under 700ma of current. Even at this rate the life would have been cut considerbly as the Luxeon 1 watters are happy around the 350ma range.