identify XPG vs XPC?

VegasF6 · Apr 1, 2010

Picked up a light recently from a budget company and I am quite suspect of it. Claims to be XPG R5 but doesn't seem as bright as I would like. In addition, in high mode it has quite a strong blue tint and fades quickly, but in lower power modes has a much better color.

A quick glance at each respective data sheet seems to show identical dimensions on the ceramic substrate. I didn't see dimensions for the die itself. One possible hint would be the middle picture on the left side of page 14 of the XP-C data sheet
http://www.cree.com/products/pdf/XLampXP-C.pdf
It seems to have sort of a crescent shape below the dome, but I can't tell from the picture what that is. Is it a cutout of some sort? I don't have a known XP-C for comparison.

If anyone could post a pic of both LED side by side for reference, I would appreciate it.

Thanks

rav · Apr 1, 2010

VegasF6 said:
Picked up a light recently from a budget company and I am quite suspect of it. Claims to be XPG R5 but doesn't seem as bright as I would like. In addition, in high mode it has quite a strong blue tint and fades quickly, but in lower power modes has a much better color.

A quick glance at each respective data sheet seems to show identical dimensions on the ceramic substrate. I didn't see dimensions for the die itself. One possible hint would be the middle picture on the left side of page 14 of the XP-C data sheet
http://www.cree.com/products/pdf/XLampXP-C.pdf
It seems to have sort of a crescent shape below the dome, but I can't tell from the picture what that is. Is it a cutout of some sort? I don't have a known XP-C for comparison.

If anyone could post a pic of both LED side by side for reference, I would appreciate it.

Thanks

Photo by ekke.

Left XP-E, right XP-G.

If the chip is smaller than in XP-E is the XP-C.

brted · Apr 1, 2010

VegasF6 said:
Picked up a light recently from a budget company and I am quite suspect of it. Claims to be XPG R5 but doesn't seem as bright as I would like. In addition, in high mode it has quite a strong blue tint and fades quickly, but in lower power modes has a much better color.

The XP-C only has 2 strips on it, whereas the XP-E has 3 as shown in the picture, and the XP-G has 4.

I've read about some of the XP-G's from budget places being "angry blue" and suspect that the LED is being direct driven and then overheating. Try a partially discharged li-ion to get the input voltage down (assuming this is a 1-cell light) and see if that helps. The problem may not be with the LED, but the driver. Also be aware that some lights are claiming they can be used with two 16340's, but people are burning their lights out with two cells, so you're better off with one 18650.

VegasF6 · Apr 1, 2010

Perfect, that is exactly what I wanted to know. (Especially counting the strips.)

The light is a single cell. I have only tried it with an 18650 at 4.17 and haven't measured the current yet, or tried it on the power supply. But it doesn't seem as bright as even a couple of my other budget XP-G. (One I got from DX I am quite happy with.) I expect that if it was being driven hard enough to turn blue (as in well over 1.5 amps) it would be intensely bright at the same time. To the best of my knowledge, XP-G has only been released in R4 and R5, is that correct?

VegasF6 · Apr 1, 2010

Well I just hooked this up to the P.S. and at 3.7-3.8V it is drawing 2.2 amps! I was afraid to go any further. With this driver, this drop in is absolutely useless. Perhaps with a different one, maybe a 7135x4.