Defective CREE emitters in my budget lights, C2 & EYJ U2

Recently I changed the led in my Ultrafire C2 due to lack of output. I decided to take a closer look at the removed Cree. This is what I found.

The die phosphor is discoloured, splotchy or tainted. This one is from the C2 with low output. Since it is hardly used I guess it's a manufacturing error.



This is what it what it should look like. This led gets the same current as the one above. There's some optical distortion from the glass dome, but the die looks good.


The Cree in my EYJ U2 also has discolouration in the die phosphor, but much less than the Cree from my C2 . My EYJ U2 also have very good output so far. But the discolouration does make a small portion of the hotspot appear yellow-brownish compared to the rest of the hotspot. I didn't notice this until today when I looked for it. Half of the hotspot from the defective C2 Cree was yellow-brown. Both lights are from DealExtreme. It was my decision to change the led instead of sending it back.
Stefan

I ordered a seoul light from DX a month ago and i recieved it after a week and it didnt even have a seoul led in it...it was a luxeon so i sent it back and now they still havent even shipped my replacement yet. dunno whats goin on with it

I would not be surprised if the parts is not poorly mounted to the board and one side of the part is getting a lot hotter. We have seen some quality issues with Seoul, but other than domes falling off Cree, the quality has been good.

Semiman

What exactly does the dome do on a Cree? My dome in my cree_elly was loose from the start and it finally fell off. The light output doesn't seem any different with the dome off so I wonder what exactly its purpose is?

From what I have gathered it's a lens. It floats on some silicon gel compound, thats why they feel loose. The silicon is primarily for thermal management and to get the correct light dispersion pattern I think. I'm sure there is more than that to this. Luxeons also have silicon gel, but they have lenses made of polycarbonate/plastic material.
Stefan

Hello, Stefan. I have a question for you about swapping an emitter, and I thought it better to post it here in public rather than PM so that other members can reap the benefit of your advice.

I have an Ultrafire C2 HA-III, and I absolutely love it. For the price, it has very nice throw, but far more importantly, it has a truly terrific amount of sidespill. I think that if the sidespill were just a tad brighter, this light would be really great, and a perfect companion to my Tiablo A8.

I am trying to learn about how difficult/easy it is to swap an emitter, and I was thinking of trying with this light.

So, I have three questions:

a) What emitter does the Ultrafire C2 come with, stock?

b) What is the best emitter to swap it for, which will increase its brightness, while maintaining the same runtime off 18650 cells, and also maintaining the same exact amazing amount of sidespill?

c) Where is a good place to get that emitter?

~Thank you!

LEDAdd1ct (Bryan)

LEDAdd1ct said:

a) What emitter does the Ultrafire C2 come with, stock?

b) What is the best emitter to swap it for, which will increase its brightness, while maintaining the same runtime off 18650 cells, and also maintaining the same exact amazing amount of sidespill?

c) Where is a good place to get that emitter?

Click to expand...

a. Mine came with a Cree P4.
b. I tested it with an SSC P4. Didn't like it, so I put in a new Cree P4 on a filed down star. I again swapped emitter to a Cree Q2 (which are cheap now) when I swapped driver recently. But now that Cree Q5 are available....
c. I got mine from the big vendor in Hong Kong which is usually referred to with two letters, starting with D.
Stefan

Stefan: A bit off subject...How do you get the head loose on the Edward J U2 clones? I'd like to try a Q 5 star in mine...they are glued on I believe.

Thanks

Thank you very much, Stefan!



~Bryan

Lighthouse one said:

Stefan: A bit off subject...How do you get the head loose on the Edward J U2 clones? I'd like to try a Q 5 star in mine...they are glued on I believe.

Thanks

Click to expand...

I haven't gotten the whole head off. But I did get the bezel/glass off by trying hard to unscrew it. Once off, the reflector came out, the star is held down by 2 screws. I added some Arctic Alumina under the star since it was dry.

Bradley

Lighthouse one said:

Stefan: A bit off subject...How do you get the head loose on the Edward J U2 clones? I'd like to try a Q 5 star in mine...they are glued on I believe.

Thanks

Click to expand...

You don't. It's threadlocked with the red stuff. Just screw out the led pill with a pair of pliers after you take the bezel and reflector out. I cut down my EYJ U2 recently, took off the fake switch part. I put it in a vise and applied my plumbers wrench, the epoxy used to threadlock is demonic. It's now a lot shorter.

oops

Hmm either it got super hot when turned on due to lack of thermal interface quality (thermal grease, un-even solder) or they heated it too much when soldering it to the star (assuming it was a star).

StefanFS said:

... b. I tested it with an SSC P4. Didn't like it, so I put in a new Cree P4 on a filed down star. ...

Click to expand...

Hi StefanFS,

why didn't you like it?

I am asking because I am eventually planning to do this mod ... :thinking:


tl

It produced a horrible beam with the P4, also weaker output than with CREE.
Stefan

StefanFS said:

It produced a horrible beam with the P4, also weaker output than with CREE.
Stefan

Click to expand...

Thank you!

Interesting - the reflector is rather wide and not very deep – I thought he should
work with the SSC …


tl

taschenlampe said:

Thank you!
Interesting - the reflector is rather wide and not very deep – I thought he should
work with the SSC …
tl

Click to expand...

It works, just not as well in my opinion. Try it, maybe you'll like it, just make sure to use another driver as the stock driver puts close to 1.2 A to the led. and then :sigh:.

Stefan