cree xre vs domeless cree xre vs Lumileds K2 and Lux3 in 3D Maglites! Lotsa pics!

This is the thread that got me started on this project.

Here ya go!!!
Hotlips heatsinks rule for cree xre's.
The lense and it's retaining ring on the modded cree xre got tossed. :banned:
It's just the led die and a bit of gel on it, but it works!


The other unmodded cree xre was left completely stock.
I ground off the sides of the hotlips pedestal instead to keep the led's underside electrodes from shorting.


The four contestants, each with new Rayovac alkaline batteries.
Upper left is the modded cree xre measured in at 440 milliamps.
Lower left is the stock cree xre measured in at 400 milliamps.
Upper right is a Lumileds K2 UWOK bin measured in at a strong 1,620 milliamps!
Lower right is a Lumileds Luxeon3 UWOJ bin measured in at 1090 milliamps.


Another close up of that modded cree xre in the silver Maglite below.


Here are all 4 lights against the wall.
From left to right..
UWOK K2, UWOJ Luxeon3, unmodded cree xre, modded cree xre.


Same lights aiming up.


Same lights without thier heads.
Notice the second from the right with the narrower beam agle.
That is the unmodded cree xre.



Unmodded cree (left) versus the modded one on the right.


The unmodded one looked like a performer didn't it?
The camera showed it to have a powerful hotspot right?

Let's go outside for the truth.
Left is the modded one, right is the unmodded one in both pics below.


The stock cree xre's narrower beam angle meant that there was less light hitting the reflector.

Those cree's are not in max focus with the mags. They need to be raised more. You can do this by cutting down the mag reflector, or raising the pedistal but the former is what you'll have to do since they are already mounted...

According to Mac, the unmodded one should have a brighter hotspot than a K2.... And yours do not look like that... EDIT: I see it's only 400ma, but still the reflector will bottom out on the hotlips, so there is more focus to be had..

BTW awesome work on removing the copper ring around the led!! The copper ring would block a lot of light if you just removed the dome and stopped there.

How'd you remove the reflector?

Kryosphinx said:

How'd you remove the reflector?

Click to expand...

With these tools.


I also managed to get the cree Magmods reflectors trimmed down a little more.
Left to right is; UWOJ Luxeon3, UWOK K2, modded cree xre, stock cree xre.


Here is the way I was holding them for the beamshot.

Hi guys. For a data point, the very first sample I got some time ago ended up loosing its dome (there was a known issue of good dome retention on these samples). In the integrating sphere, i noticed a loss in flux afer the dome got knocked off. I don't know if this is to be anticipated in all cases or not. :shrug: I have this silly idea that Cree put the dome and silicone goo there for reasons beyond just protection of the die and bond wires but I could be wrong. I would be suspect of lumen maintenance in the domeless case but I can't justify this.

Here is a pic of a stock Maglite at 900 milliamps versus the cree xre Magmods.
Stock on the left, modded cree in the middle, stock cree on the right.


Another shot of the same lights indoors.


Remember, the stock light is using more than double the power as the other 2 are and is still dimmer. :thinking:

Don: yes without the dome a lot of light gets trapped in the copper ring. But Since 3rdshift cut the ring off, all the light should be escaping.

3rd: Did you grind off the copper ring or pry it off? Does it look like it could be pried off instead of ground down?

I see you removed the reflector and the lens. Interesting idea. Additionally removing the reflector, you often end up with a small glop of very soft sticky silicone gel, but sometimes you take off the bond wires and/or the phosphor with it. If you get it off just right, you end up with a rounded dome of silicone gel, that would reduce the effect of light losses that happen when just removing the lens only. Have you noticed how the unprotected silicone layer over the die starts smoking at higher drive currents yet? It is kind of cool.

What I'm trying to understand is why some of your photos seem to contradict each other. Could please help me to understand?






Then we have things like this one:




I was also noticing one of the lights has a clear witness of ?AA epoxy? and the other one has nothing showing, is it also ?AA epoxied down?




Also, what is your current running to the K2 an Lux III lights?


Which bins did you use in the two XR-E lights, they are obviously very different tints, and not from the same tint bins. Is the Green one the P4 WH binned ones that Erasmus was selling? Is the white one one of those P2 WC bins that someone was selling?

Thanks for posting your results!

NewBie said:

Which bins did you use in the two XR-E lights, they are obviously very different tints, and not from the same tint bins.

Click to expand...

You might want to avoid the term "obvious" bad mental hygene. Almost a sure way to make sure you are wrong.

Taking off the cap changes the color of the beam or at least of the spill. I pulled off the dome from one of these XR-E lights too.

I was able to put it back on and off to see that I did not damage the light- and there was again a change in tint.

I think I like the tint betterr with the dome off- I wonder if it wont work better in older lights that way it will be something interesting to check.

:wave:

All led's pictured were Arctic Alumina epoxied to thier heatsinks.
The one photo showing the unmodded cree without it was taken right before I AA'ed it, to show the importance of a good fit before sticking it on.

How does the photo of the 3 lights contradict the other photos?

The cree xre's were all purchased from member Nitroz in the group buys and pass-arounds part of cpf.
All my cree xre's on hand are the same bin at this time.
The Lumileds leds were purchased from Photonfanatic.

The grinding on the metal ring was needed to allow my sharpened screwdriver to get in there and pop off the lense.
Then I used the sharpened screwdriver to gouge out some of the gel where it met the ring.
This was needed to keep the ring from taking all the gel with it when I pop it off.
Then the screwdriver was put in under the ring to pop it off.

That was when I noticed the warmer tint coming from the led.
Just an invitation to drive it harder imho. oo: :naughty:

Heheh, have fun!

On a side note.
The unmodded cree xre's metal ring is a short circuit hazard for anyone new to soldering.
I had to "paint" all the surfaces to be soldered 1st with a little extra rosin flux.

That was when I finally managed to get the right amount of solder to go right where it was supposed to.
Before this, I almost threw the hot soldering iron accross the room during this project.

Many rosin core soldering wire spools don't have an even, or consistent amount of rosin in them as it turns out.

So, a little extra rosin flux added on seems to help.

I've gotten the hang of soldering the xre no problem now. Just tin the pads first before you mount it to a heatsink. Then you can mount it, then solder a lot easier. Even with my 1980's low wattage radiosnatch iron.

Oh yeah very fine solder works the best for delicate stuff like this. Not those pencil lead large solder wire...

Update:
I measured the unmodded Cree XRE with a 4rth battery at 870 milliamps and it is quite bright but with no change in the tint as far as I could tell.
I will try to transplant both Cree XRE's from thier 3D hosts into 4D hosts this weekend.
I used 2.2 ohm 5 watt rated resistors with both of these to keep the amount of power close to thier 350 milliamp specs in the 3D's.

Have you ran the bare die one for a long time to see if it gets hot enough to boil off the exposed silicone oil?

I still don't get why does the tint shift when the dome is removed, Are the domes vaccum sealed? Does oxygen play a part on it?

Thanks!
AlexGT

Just thought I would add my experience to this thread. I have an Ultrafire C2 that had an almost purple tint before the lens popped off. Now it is a pleasing neutral white. I can't think of why either.