Great mod, once again!
Not to be a Debbie Downer, but can 3xAAA alkalines run this thing reliably? Isn't that really stressing the cells to the point that they will rupture? I'm curious how many amps the thing is pulling. And what about 3xAAA NiMH, will they be driving the XM-L too hard in DD?
XM-L may stress them, but a Nichia will not. On the ones I have checked with a meter, I never saw more than about an amp out of the AAA Alkalines with any led. I have never had one leak, even when leaving the light on till it got dim as hell. It’s probably a possibility, but I have just never seen it.
Run 3xAAA NiMHs. They work fine. I'm just making these to sell to "regular people" and they don't want to screw with rechargeables, but prefer throw aways. NiMH will not hurt the leds. With AAA being such a low output, the voltage drops immediately and you're not putting much over 3 volts in the led. With Alkalines, they read higher (about 4v to start) and then they drop off fast. Remember also that I do not mod the battery holders, so there is considerable V/mA loss thru them. I don't mod them on purpose, to have the resistance there as a buffer of sorts.
That makes perfect sense, thanks O-L :)
Picked up two packs (4 lights) at my local H.D. Figure I'll mod all four eventually. Still a good many at my store.
-Garry
Wow, incredible job Justin! As somebody else said, a quick 10 minute mod for you would turn into a 10 hour ordeal for me. 
Your craftsmanship is very admirable. Frontpage’d and Sticky’d.
Impressive and for that money, wow :D!
Sorry I missed this post. I think overall that these are no better or worse than any other $5 light. Since you get two for ten, they are $5 lights. They all had small scuffs or scratches on them and that tells me they were just bulk packed in bins, when they were made. The threads are just ok. They are not too tight and have some play. Like I say, a $5 light.
Hello, I’m new to this forum. I like the mod a lot, could I ask you where did you buy the Cree XM-L or a good source for the Led’s with the boards? A link would help, thank you very much in advance.
http://www.intl-outdoor.com/led-c-107.html
There’s a start, all three of those sites are trusted and if your unsure, just ask before you buy, welcome, hope you have fun here laszlomdq
Thanks for signing up, laszlomdq!
Thank you very much for the links, I can’t wait to make my first mod.
Thanks a lot!!!
I just want to comment that these lights make excellent "mules" for tailstanding "candlelight" - even stock (stock esp. if you want more runtime I suppose). Just unscrew the head and you have a very wide even spread of light. Tailstand it and you'll light up a room (or a tent, etc. . .).
-Garry
Quick question and a little bit off topic, I have some of the flashlights from this old thread: Linky Which Cree LED should I buy? There are so many different ones that I don’t know which one to choose. Thanks again.
I'd suggest going ahead with an XM-L (neutral white T6 3C - see International Outdoor - probably want 20mm ) and run it like this one - direct drive single mode. I think Old Lumens did a mod similar to this one from those same lights - would have to search for it. Wait! Here it is! I see O-L beefed up the heatsink. I also saw in your linked thread that dchomak modded the heatsink with pennies.
You could go with the Nichia 219 as well for better CRI, but it won't be nearly as bright.
-Garry
Believe it or not, the Nichia is darned near as bright as the XM-L. I believe that is because the AAA cells can’t put out the amps necessary to push the XM-L, so it’s all limited to the AAA bottle neck.
Thanks a lot for the suggestion. It’s confusing choosing the right led since there are so many out there. For example why not the XM-L T5 or the U2?
You could use a T5, or T4, an XP-G or G2. Any number of leds can be used. It's all in what you want for output and use. As I said, the 3AAA batts limit the output anyhow, so just decide on a small hot spot or larger hot spot. A Nichia would give you a smaller hot spot. A XM-L will give you a larger hot spot. An XP-G will be somewhere in between.
If you don't know, then it's probably good to do some basic searching. Google image search for Cree XM-L, or Cree XP-G or Nichia 219 and add "beam shot" or "tint" and you should find some images showing tints or at least beam shots. Other than that, I would suggest the Nichia for better indoor color rendition and the 5700k and higher crees for "seemingly" brighter beams outdoors.
Ok, thank you very much. Is there any other supplier to buy the of Led’s? I tried Digikey but didn’t find them.
Mouser is another one.