# Cree XRE thrower



## Hmmm (May 30, 2012)

I'm working on a aspheric lgith. I'm Thinking of using a peltier to cool the led, run the led at around 2 amps, machining a costum light, and controlling the peltier with a attiny 13a and a transistor. I found out that the five cree xre q5 leds I have are ez900 ones. I discovered that after accidentally de doming 2 of them when desoldering. :sigh:. That was sad. I can't find any tests that show at which temperature they run the best. I saw one test here that showed someone got almost 500 lumens out of one with a similar setup.

I'm thinking of using the 62mm dx aspheric if I can't find any nice large ones. I'm took 2 old pennies, sanded and then soldered them together, drilled a 3/16 hole through them and soldered a brass piece of rod in. I couldn't find any copper rod. I'm planning on directly soldering the led to it and sanding the rod down to a few mm above the pennies. I'm going to solder the pennies to 1/4" thick piece of copper to act as a heat spreader for the tec.

How does this sound?


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## bose301s (May 30, 2012)

Hmmm said:


> I'm working on a aspheric lgith. I'm Thinking of using a peltier to cool the led, run the led at around 2 amps, machining a costum light, and controlling the peltier with a attiny 13a and a transistor. I found out that the five cree xre q5 leds I have are ez900 ones. I discovered that after accidentally de doming 2 of them when desoldering. :sigh:. That was sad. I can't find any tests that show at which temperature they run the best. I saw one test here that showed someone got almost 500 lumens out of one with a similar setup.
> 
> I'm thinking of using the 62mm dx aspheric if I can't find any nice large ones. I'm took 2 old pennies, sanded and then soldered them together, drilled a 3/16 hole through them and soldered a brass piece of rod in. I couldn't find any copper rod. I'm planning on directly soldering the led to it and sanding the rod down to a few mm above the pennies. I'm going to solder the pennies to 1/4" thick piece of copper to act as a heat spreader for the tec.
> 
> How does this sound?


Pennies aren't copper, they are copper plated zinc. I would not use them for this.


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## Torchaddict (May 30, 2012)

bose301s said:


> Pennies aren't copper, they are copper plated zinc. I would not use them for this.



Not entirely right, but there's some truth to this. I modded my Arc6 with penny shims (1981 and older), these are 95% copper and 5% zinc. But yes, 1982+ are mainly zinc (97.5%). Just use the older ones.


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## Hmmm (May 31, 2012)

I used the old ones. I'm planning on ordering this http://www.ebay.com/itm/DC-5V-19-4W...474?pt=LH_DefaultDomain_0&hash=item4cfa22455a peltier.


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## Hmmm (Jun 2, 2012)

help? I'm thinking of using the 75mm aspheric from dx, saabuster said it is poor quality. Has anyone else had something positive to say about it?


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## Walterk (Jun 3, 2012)

The DX 75mm can be good, but if you are unlucky it is bad, it is not consistent quality. 
On Ebay there is the shop called top-ledlight, and another called wellparts, they have 75mm aspherics. I would try those first.


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## The_Driver (Jun 3, 2012)

Walterk said:


> The DX 75mm can be good, but if you are unlucky it is bad, it is not consistent quality.
> On Ebay there is the shop called top-ledlight, and another called wellparts, they have 75mm aspherics. I would try those first.



I tried to find those on ebay, but coudln't. Could maybe send me the links to them or maybe post them here (don't know of this is allowed)?


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## Hmmm (Jun 4, 2012)

I will look for those. Today I built a new heatsink with a piece of 3/16" copper sheet, some pcb board, and some brass rod. I soldered the led to the brass and i put together a simple constant current supply set for 2.2a. I'm planning on driving it and the peltier off of 2 lifepo4 18650s in series. I'm having some problems with the led icing over. Should I tape a desiccant pack in the light head once I make it and just fully seal it and not open it again? Maybe assemble it in a freezer? I'm planning on pwm controllening the peltier with an attiny. I'll have a temperature sensor on the hot and cold side and if the hot side gets above a certain temperature I'll lower the power of the peltier and the led and check until the temperature is a certain preset max.


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## Hmmm (Jun 4, 2012)

Is this the one? http://www.ebay.com/itm/100W-LED-co...aultDomain_0&hash=item2a0ee62a5a#ht_584wt_668
It looks the same as the dx one. One question I have is by it saying: 20-65 beam angle. Is it possible to get a lower Angle. I haven't taken physics yet so I don't know this stuff.


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## Walterk (Jun 4, 2012)

There is no such thing as a lens with a certain beam angle. But for this one; I would try it.


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## Hmmm (Jun 4, 2012)

ok thank you. What is a max recommended current for a cree are q5 ez900? I'm driving mine at 2.2a and have read that is too much for it. I understand the ez1000 can be driven as high as 2.5a with extreme cooling. I'm been running mine at -30 degrees C which is lower than i will be in the light.


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## Hmmm (Jun 15, 2012)

help?


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## Hmmm (Jun 15, 2012)

where does the lens focus?


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## Walterk (Jun 16, 2012)

The 66mm lens that I have has a focal length of around 40mm. 

You have to be carefull with the led, better start at low amperage and see what it does when the current goes up.
1,4 Ampere is about standard, 1,8 is about the highest sensible but if your set up is good AND you have luck with the led it can take 2,2 amp.
You just have to try...

What do you use for power or driver for the led?


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## Hmmm (Jun 18, 2012)

I'm planning on using 4 A123 Lifepo4 18650s in a 2s2p configuration, with a switching buck driver for the led and I will directly power the tec.Currently I have the led directly soldered to a b rass bar abut .5cm long which is connected to a peice of 3/16" copper.


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## Walterk (Jun 20, 2012)

Variable output driver would be great.
The TEC would be more useful if you ad a fan to the heatsink most likely.
Any picture of the set up?


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## Hmmm (Jun 20, 2012)

i'm still waiting on the tec from ebay. i have several but i have trouble removing them from the heatsink. Anyway to remove thermal glue?


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## Hmmm (Jun 21, 2012)

here is the assembly:
i'll test it:


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## Hmmm (Jun 23, 2012)

i'll post some new photos tomorrow, i'm building a better setup.


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## Walterk (Jun 23, 2012)

The principle is good.
Really good cooling might give you around 10%, maybe 15% more output. 
I think the heatsink on the back should have fins and might be a bit larger, the larger the better the temperature is taken from the led to the air.
And maybe a bigger plate on the front, the same size as the peltier?


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## Hmmm (Jun 29, 2012)

that sounds good. It will go in a light. I'll post some photos of the design I have planed. It would thread onto a maglite body.









I have a lm35 to monitor the hot side, if it gets above a certain temperature it will flash and a another higher temperature turn off.


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## Walterk (Jul 1, 2012)

Oh my... I can't make sense anymore of that stack of beautiful red copper....What I expected was a led, glued on a coppersheet to spread over the whole surface of the Peltier, then the Peltier itself, and then a rather large heatsink with fins on the back and a fan on it.

I have never played around with Peltier, but I understood all it does is moving heat from one side to the other. 
But in 5 or 10 minutes the copper on the back is full of heath, saturated, and then it overflows on the front....
Just the copper plate is not in good proportions to the effort and electric consumption of the Peltier to my opinion.

You need exposed surface area, preferable matt black. And if you don't, you should have at least fins, and preferable a fan to raise the amount of air coming in contact with the exposed surface.
Do you have a luxmeter ? Or digital multimeter? Measure lux or amps before and after you ad a fan. 
I mean, if you pull out all this effort and really want to see what Peltier can do, better make it worth !

I know there was someone with a fan on a maglight, right behind the head but can't find it.
I did find Ra's example of a fanned heatsink, much less weigth and more efficient then your setup, mostly because he uses a fan.

And hey, here I found Yarob's Mag lite with TEC.

There is another Mag-mod, without TEC but with a square fan inbetween head an body.

And this link


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## Hmmm (Jul 12, 2012)

That is just the the heatspreaders, the led, and the peltier. I'm thinking of turning a costum head on a metal lathe. that heatsink looks interesting, but i'm not sure if i want to loose waterproofness. I'm thinking i will just have it be large and have alot of finns. the hotside won't have more than 20 watts on it. 10 from the led, 10 from the peltier. If the temperature gets way too hot it will dial back automatically.


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## Hmmm (Jul 13, 2012)

this is my head plan, it will screw onto a maglite head. on a different version i have the threads but i forgot to add them to this version.













i'm planning on making a a driver which fits in the escess area around the led setup. a circle with a hole cut out. i'm currently taking a more advanced programming class than was offered at my highschool, ecs30 at uc davis to help me alittle with programming and an electronics course to help me with driver design.


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## Walterk (Jul 13, 2012)

Looks great, nice approach, you have a mission on hands 

Don't spare on getting mass close to the led for heatspreading. 
Fins on the front of the head are less functional as fins close to the led.


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