deltaH
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The wee 100w LED torch project
Okay, so once in a blue moon, I like to undertake some simple electronic project that's a little mad and probably won't work.
So I decided to build as wee a torch as possible with a 100W led module 
Size matters, I want SMALL and BLINDING 
I have ordered the following bits and pieces from aliexpress.com:
One 100W cool white led and 100W blue led for good measure
http://www.aliexpress.com/item/Ultra-Bright-10W-20W-30W-50W-...
These are 36V LED's, so for my wee powerplant, I ordered ten 3.6V rechargeable Li-ION d25mm X 5mm button cells which I will stack in series to make a
compact 36V d25mm X 50mm battery (yes I know I will only get a few minutes of power from them, but that's fine, they're rechargeable).
http://www.aliexpress.com/item/10PCS-Lot-LIR2450-3-6V-Button...
Lens holder and reflector
http://www.aliexpress.com/item/1Set-High-Quality-30W-50W-100...
Now the main problem for this sucker is going to be heat dissipation and management. Normally one sticks on monstrously big heat sinks onto these
LEDs, but I don't have the space for that in the wee LED torch.
So I bought three wee 30mm X 30mm X 10mm 12V DC brushless fans that I plan to connect in electrical series and run off my 36V battery.
http://www.aliexpress.com/item/Super-small-mini-DC-12-v-Brus...
Two can sit above the battery at the top of the torch side by side and perpendicular to the vertical LED, the other will probably sit at the front or
back of the torch || to the led module and perp. to the other two fans that sit at the top.
Now I want to transport the heat from the front LED to the top two inline fans in some wee fashion. I am hoping to do this with heat pipes, like
laptop heat pipes, if I can find them (they already have wee heat sink grills attached to their ends) or make a fudged version myself if that's
possible with a copper tube, some low boiling solvent (alcohol?) and some cotton strings for the wick.
If you don't know what a heat pipe is, it's NOT simply a copper rod!
https://en.wikipedia.org/wiki/Heat_pipe
I also bought these two wee heat sinks in case I need them, for example if I can't repurpose laptop heat pipes with existing heat sinks.
http://www.aliexpress.com/item/2Pcs-Aluminum-Heatsink-Coolin...
I regret not getting wee'er ones, they're a bit big 
The battery might also get too hot so I might need to put thin pieces of metal between each cell to also create a radiator across its length. The fans
sitting at the top can pull up air through them before blowing through the LED radiator on the ends of the heat pipes or some such, I will work it out
in better detail once I start fiddling with it.
The whole thing should comfortable fit into my hand with as little as possible visible, except for the bulb (and blinding light) and fans open at the
top  I'm planning to grip it on the sides with my hand turned up so that the
fans are open at the top.
A wrist mount with velcro straps might be cool, like these Star Trek Voyager ones...
...but I will have to practice the blank fearful expression in the mirror some
Thoughts and suggestions on the design, possible problems ect. would be greatly appreciated!
[Edited on 11-10-2015 by deltaH]
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deltaH
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Not getting much luck sourcing laptop heat tubes this side and the aliexpress ones are pricey, $20+ for two
Oh well, guess I will have to build my own. Vertical or slanting ones are easy, just fill a copper tube closed at one end with some acetone, heat
until acetone fumes come out on the other side and then seal while hot.
Horizontal ones need a wick though to return the liquid. Ideally that's a copper sponge sintered onto the inner wall, but that's a pain to make! I'll
have to macgyver something simpler.
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aga
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Easy : Take a handful of Laxatives and wear White Shorts.
Go to a supermarket (lots of people) and film yourself there.
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Detonationology
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I've seen videos of some LEDs on youtube that were purchased from China and had many burned out cells that resulted in uneven lighting at lower power
settings.
“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
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deltaH
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Oh joy... well at $3, probably best to curb my expectations!
These come with alibaba's 'return faultless goods' guarantee, so I can return them for any reason whatsoever and get my money back
[Edited on 13-10-2015 by deltaH]
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Sulaiman
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I have two cheap 100W white LED modules via eBay, one cool, one warm.
each is 10 parallel strings of 10 series LEDs arranged in a 10 x 10 array.
If I wind up the voltage slowly I see individual LEDs get brighter in some random sequence.
When all LEDs are 'lit' at rated current the emissions of individual LEDs are fairly similar (dazzling) intensity.
I can understand why different 'columns' of LEDs light up at different voltages but not why different LEDs in the same column do not come on all at
the same time/voltage.
So, good, cheap but not perfect.
I use an old style CPU heatsink with fan and operate at about 50W.
The good news is that 8 x 18650 lithium cells in series can be directly connected with no regulation required... for a while... great torch
P.S. almost any inert grease is better than nothing or thermal paste that is too thick or dry.
edited due to memory failure, 8x series 18650 cells, not 4x ... sorry
[Edited on 13-10-2015 by Sulaiman]
[Edited on 13-10-2015 by Sulaiman]
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Twospoons
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Quote: Originally posted by Sulaiman  |
I can understand why different 'columns' of LEDs light up at different voltages but not why different LEDs in the same column do not come on all at
the same time/voltage.
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Probably because un-binned LED dice can vary 4:1 in brightness at the same current. And since unbinned dice are the cheapest ...
If anyone is interested in quality of light, as well as quantity, then have a look at the high CRI 100W module from yujiled http://store.yujiintl.com/collections/frontpage/products/bc-...
Yes its expensive, but its ideal for video lighting. I have bought some of their other (much cheaper) lamps in the past, and the difference in light
quality is very noticeable.
[Edited on 13-10-2015 by Twospoons]
Helicopter: "helico" -> spiral, "pter" -> with wings
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Sulaiman
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My son does video productions and he tried my battery-powered version,
verdict = rubbish !
uneven intensity and colour temperature using matching LED lens/housing.
fan noise was also noted.
no problem, still an awesome torch and one day it may look like a torch
deltaH, P.S. I've not done the math but I'm pretty sure that weight or volume wise,
a heat-pipe system cannot be as efficient as LED/Heatsink/Fan(s) system,
but does give more flexibility in mechanical layout and airflow considerations.
[Edited on 13-10-2015 by Sulaiman]
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deltaH
Dangerous source of unreferenced speculation
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Can you believe they make +500W LEDS now 
http://ce.citizen.co.jp/lighting_led/dl_data/datasheet/en/CO...
I can't believe the size, just 38mm square
Unfortunately, I can't afford it 
Here's a heat sink for the 400W citizens:
http://www.sunon.com/index2/publication_page.php?pkid=11
Note the heat pipes (I think).
[Edited on 14-10-2015 by deltaH]
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Sulaiman
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as an example, compare CLL040 with a simpler type, e.g. http://uk.farnell.com/sanyo-denki-sanace-fans/109x7612h1126/...
smaller and lighter.
For a 500W LED with 38 mm square mounting area, I guess heatsinking will be expensive.
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