Newbie just finished building M@G Cree (5 cree)

[nanotech17]

WT@#$%!
that is bright!
very nice.
one more question - is this direct drive?

 

[rizky_p]

Thanks for sharing!!

How did you solder the cells end to end like that?
How do you "aim" the emitters... is it very sensitive to how on-axis they are?

Nice work

I Pressed each battery quickly after i remove the solder and before the lead start to harden. i have to apply a blob to each contact, melt them and then joins them while they are hot...

they are being pressed down hard by the front plastic windows, so they are in allignment automatically and lays flat. DX Reflectors has flat bottom that sits nicely at the emitter's solder point. You have to isolate this otherwise you will get a short...

@nanotech17: yes it is direct drive. I am surprise by its runtime so far probably because of the nature of low vF of the Cree Q2(measure [email protected])

@Vbest: Sure

@sawlight: i live on the other side of this planet.

@drew2001: it started as Hotwire mod, but turns out into MagLED mods.

 

[rizky_p]

Can anyone advice me whether it is safe to run all the Crees @2A with my setup? i am using Multisink from download and all three(oops! edit:five) emitters are using thermal compound and pressed hard by the windows..it is hot already with current setup but i was thinking of bumping it up a bit....

Thanks.

 

[Bimmerboy]

Yep... you've been bitten by the bug.

Nice mod, Rizky!... and nice indoor pool!... hehe.

2A for those Cree's? Perhaps someone more experienced will chime in, but that may not be a good idea. The heatsink may not be able to draw heat away fast enough.

Thing looks pretty darn bright as is, and 2A may be well past diminishing returns.

 

[IsaacHayes]

Nice. I was thinking of going 5 instead of 4 for my 3C mag as I would only loose 15min runtime. 1 hr vs 1hr 15min isn't that big of a loss for gaining ~200 lm!

Cool find on the DX reflectors. I have bare emitters (one less thermal interface) and soldering wires directly to the emitters might interfere with the reflector sitting down enough. Are you saying even with stars the reflector touches the wires?

Cree @ 2amp, not in your setup. Too many emitters, too much heat. I have a project with a cree on a huge CPU heatsink, at 2amp (with a focusable TV projection lens). After 1.5amp you don't gain much more, just heat. But if your heatsink is already hot you likely won't gain anything as the hotter the LED the less light they make.

 

[LukeA]

Can anyone advice me whether it is safe to run all the Crees @2A with my setup? i am using Multisink from download and all three(oops! edit:five) emitters are using thermal compound and pressed hard by the windows..it is hot already with current setup but i was thinking of bumping it up a bit....

Thanks.

Dissipating 40W from that small an area isn't going to go very well.

 

[rizky_p]

Sharper Beamshots if you dont mind.... that Sodium light is annoying i know, wish i had M@g623

Bimmerboy: yeah it is bright enough i guess i will have to make bigger custom MagHead to pack more emitter inside. No that is not an indoor pool, it is only a plastic net to keep falling leaves from the trees up ahead...

@LukeA: did not realize that it is 40watt of heat already...

@IsaacHayes: let me know when your 5 cree mag is ready, my plan was to pack 6 cree's but i could not find smaller reflectors maybe i have to make one
as with the DX reflectors, yes they sits flat on the emitter shoulder covering the contact pads near the dome(not the pads on the star). If your solder blobs are too big yes it will touch those...keep the solder thin and you are safe.
Yes you would need to dremel the DX reflector if you were to solder directly to emitter without the star..

 

[IsaacHayes]

I guess I'll have to order those DX reflectors then! Thanks for the find! I'm running 5,000mah C NiMH. I plan to have a resistor for each LED, all of them parallel to the 3xC cells. Yes no driver but as you know NiMH has a decent flat discharge curve. And the voltage is close to that of the LEDs. Without having five separate buck/boost circuits or more cells and wire in series this is the simplest way to run them with only 3 cells to deal with. My 3C mag was one that was re-plated in HA natural too! I should have +/- 1 hr runtime with 5 emitters, vs 1hr 15mins with 4.

I was afraid about clearance with the reflectors. I have some thin copper sheet that is flexible (I think I pulled it from an old phone, it's shielding and had a wire soldered to it). I think I will solder that to the top of the emitter pads and run that to a wire so that the amount of clearancing on the reflectors is minimal.

My heatsink is a PES2 from mod-a-mag that I have machined flat (well I did it by hand but you get the idea). I think I will try the smooth reflectors for max throw.

You can fit 7 reflectors/leds in a circle with NO wasted space. I think you should go for 7 instead of 6. That way there is no hole in the middle. I *think* 17mm reflectors fit that way... I've seen it done before in stock mag heads.

EDIT: Those beam shots are great! Really motivates me! I have a tri-luxeon3 (~200 lumens before optics) and it lights up the whole back yard. I can't wait to see what ~1000 lumens looks like. I already have the Q5's, just need the reflectors.

 

[nanotech17]

rizky_p,
do you think it is safe to run 2x 18650 cell in series to direct drive 5 crees without any resistor?
anybody would like to chime in?

 

[MatajumotorS]

rizky_p,
do you think it is safe to run 2x 18650 cell in series to direct drive 5 crees without any resistor?
anybody would like to chime in?

Personally i would add 0,22R resistor to each led...
Edit: ups, didn't see in "series"! I would add resistors if they would be in paralell.

Driving 5 paralel crees from 2 series 18650 ower resistors would be too mutch losses in them, it would be more than a half...
You need some driver..
It would be easier to drive 4 or 6 leds from 2xlions in series, see my mod in progress.

 

[nanotech17]

Thanks.
How about this driver - http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982

 

[MatajumotorS]

Thanks.
How about this driver - http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982

It is buck driver, you could use it if you have had 5-6 li-ons in series.

 

[nanotech17]

It is buck driver, you could use it if you have had 5-6 li-ons in series.

Thank you mataju.

 

[rizky_p]

Thanks.
How about this driver - http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982

i was thinking of geting the same driver from kai since it seems to be out of stock Indefinitely then i choose to go with the resistor...

 

[IsaacHayes]

Just be careful with unprotected Li-Ions in series. I would only do protected in series.
Since my battery voltage is so close to voltage of the LEDs, a buck driver would drop some voltage anyway and likely fall out of regulation right away. So instead of dropping .7v through a diode in a driver, I'm just going to use resistors and save $$ heheh. A buck/boost would be needed for my application since hot off the charger they would need buck, and settled with a load might drop a little too low and need boost. But 5 buck/boost circuits would get costly fast!

 

[mjzraz2]

Rizky,

What Cree stars are they or where did you get them? What did you use to cut them down and is there anything to be concerned about in doing so?

Do you think if you trimmed a little off the outside diameter of all the reflectors or trimmed the threads at least, they you could have fit them all without them touching?

 

[rizky_p]

Rizky,

What Cree stars are they or where did you get them? What did you use to cut them down and is there anything to be concerned about in doing so?

Do you think if you trimmed a little off the outside diameter of all the reflectors or trimmed the threads at least, they you could have fit them all without them touching?

They stars were a standar 20mm cree star from DX Nice color BTW. I use a cutting plier i have no idea whether this is a good way or not but it works. When cutting with cutting plier some of the top portion of the stars seems to short-circuited because the top layer seems to be squeezed down and touching the lower portion of the stars just files the edges with small files to removes "the bridges" couse by the cutting plier. It feels like a wrong way of doing it, but all my stars has no damaged.

In my case, i had to trimmed a lot more then the threads to make all the reflectors fits inside and sit flat agains the LEDs.

all in all it works and the parts are cheap.

 

[IsaacHayes]

I'm on the fence to order the smooth or orange peel ones. I like throw but wonder if there will be a ton of artifacts with 5x smooth reflectors hehe.

 

[rizky_p]

I'm on the fence to order the smooth or orange peel ones. I like throw but wonder if there will be a ton of artifacts with 5x smooth reflectors hehe.

I have 1(one) smooth reflector from DX and tried it, the hotspot is rounder and more defined but not as tight/small as other deeper reflectors. More like an OP reflectors from Fenix L2D/P3D. I think it will improve throws a bit but not much. I think 5x smooth reflectors will smooth out it self over distance. so no problems there OR just buy 10 of them 5 OP and 5 SMO and put that in alternating configuration for best of both world...

 

[rizky_p]

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