(making) smallest 18650 xm-l light

Nice project there. im curious how it will do being direct driven. i would probably polish the coin where it will contact the led die and do thermal paste/glue. where was the qtc going to go? on the positive side of the battery under the coin or on the negative spring side? keep us updated thanks!

Hm, XML with QTC, smallest body, 18650... interesting, very interesting :p Want to see more projects with QTC.

I knew youre going the DIY route sooner or later. :)

Be sure to file down the coin completely. Don't know where you live but in my surroundings we have a small company named BAR-METAL that can get you a coin shaped chunk of copper for a coffee. :)

Check also OBI or similar shops. The QTC will be insterted in the tailcap i guess?

Why did you remove the pill? Parhaps you can rather shorten the reflector if size is the issue.

You can get rid of the tailcap spring and redo the tailcap for the QTC and get some space back. double coin with some spring to tweak the desirted compression for the QTC to drive it properly might be the trick.

The only drawback is that it must be "calibrated" to the size of battery used.

Smallest I know is Shiningbeam S-Mini.... But it seems to be 11,4cm long... So it's not the smallest one

Nice application for 5 cents. That's about only thing it is useful for... :)

where was the qtc going to go? on the positive side of the battery under the coin or on the negative spring side?

Under the coin (less wear), because the tailcap end will rotate.

Why did you remove the pill? Parhaps you can rather shorten the reflector if size is the issue.

Well the pill+led is just too big (20mm) + the pill fits nicely into another light that I have + I want a direct drive light, so the XM-L can get the amps it deserves.

Smallest I know is Shiningbeam S-Mini.

So that is 114mm - about 17mm more than this one will hopefully be. If there was no need for switch (just twisty), it could be sub 90mm - but that is just too much work for me :)

You can get rid of the tailcap spring and redo the tailcap for the QTC and get some space back.

I have already done that... There will be no springs in this light (no space + QTC works better without springs). It really looks like it will be a tight fit (maybe too tight)... Shortening the reflector might be a good idea if there will be a shortage of space.

Very interesting but too extreme , 3.35 x4=13.4W in a minute if the emitter survive asbestos gloves are needed

Nice moddification, but 5 cent coins are coppered steel, not copper. The smallest 18650 flashlight is Xeno G95.

the purpose of the driver is to limit current and i know the qtc pill does that, but up to a certain tightness/compression of the qtc isnt it possible that it can send too much current to the led thereby overloading it with too much amperage. it shows 3000ma max on crees website but we know that it handles over that(my MF dropin was @3.02A and others have gotten higher readings) depending on heatsinking. the qtc pill will pass up to 10A not really sure what amps different 18650s can push out.

http://www.cree.com/products/pdf/XLampXM-L.pdf

i wish i had copper coin back here :) Nice Mod btw.

The smallest 18650 xm-l torch, Hmm...

I'm assuming that it's to be driven to full power (@3amps). In that case, the ideal design would entail a copper tube just barely larger than the 18650 cell, with a solid connection between the head, heatsink, and body. The idea here is to use all of the torch to help dissipate heat, so threaded connections would be a hinderance. Like you've planned, using a qtc would definately help to save space, along with a very small reflector or TIR lens to help keep OAL at a minimum. Using the coin, if it's pure copper, seems like a good idea, but I think you may want something thicker with better contact with the body (I'm not sure how snug the fit is now). Interesting mod so far, keep us posted!

looking for a p60 laser module and stumbled upon there copper heatsinks/discs. might be worth looking at.

http://laserpointerforums.com/f64/custom-copper-heatsinks-made-order-42626.html

Why do I get the feeling that you're probably already building one in your head. lol

WWMD?

I wonder if someone had the idea of making a 1AA powered XM-L flashlight. Since eneloops can be stressed to around 8A draw a good booster circuit could easily deliver around 2A to the led. Don't see a point having a flashlight with runtimes like 5min but heck many things were done just for the fun factor. :)

Before someone try that i'm unaware of any drivers suitable for that operation. I also think it's the cheesiest idea of all. But might be fun. I bet Match does not mind doing one just for the fun factor. Making it QTC enabled might be worthwhile.


http://www.youtube.com/watch?v=_rAHnwWfsaY


"I wonder if someone had the idea of making a 1AA powered XM-L flashlight..."

I did an XM-L AA /14500 powered and it's not a circus's torch , is my current EDC despite the ugly beam due the emitter being undomed...

http://budgetlightforum.cz.cc/node/1600

And just when I thought there is no more light I need to purchase...

agree , also it led to the next step, the qtc cell...

I see many problems to make a QTC switch reliable in non twistie flashlights. Just switching battery might be a disaster (different battery length). I'm sure somone tought somethng to counter the effect... yes/no/Foy?

I finally got XM-L from lck-led so I finished modding TR-801. Works great, doesnt screew all the way, but that will be fixed in the future (with some switch modifications). I know my soldering skills are not so good, but hey it works and it works great - QTC even with spring in the tail is great for adjusting brightness (stiff spring), I also tried direct drive and it pulls just a little under 3A@4,1V. In the end I used alumunium coin - 20 haliers (old slovakian currency - 0,2 koruna) on which I mounted XM-L.

Pics (yea I really need to get some new reflectors):

You are right Budgeteer - we need to invent more reliable way to use QTC inside the flashlight... I am using foam rings around QTC, so far so good, but I know that isnt really reliable. Maybe sendwich betwen two plates would be better...

EDIT: I tested it for 15 minutes at about 2/3 brightness and the whole body does get quite hot - around 40-45 degrees C. So heat transfer seems ok.

Looks good, nice job :)