blue and green XP-E2, output tests

These tests were done already a month ago (sorry for the delay), but tonight I was finally in the right mood to type in the data, make the graph and do this write-up (I like the testing itself but it always takes some courage for me to digest the numbers and make them into edible graphs :tired: ). Thanks go to MRsDNF for donating me the red and blue XP-E2 (from Cutter, red is bin P3, blue is bin M3), and to telephoneman for the green XP-E2 (from Mouser, bin is R2), they were not easily available to me (in the meantime the red XP-E2 is at intl-outdoor).

As usual, the measurements were done with the leds mounted on copper boards clamped to a big aluminum block, the led wires were directly connected to a power supply for testing. The leds were facing up, with a small OP-reflector on top. Light bounced back from the ceiling was measured with a lux-meter. (These might have been the last leds I have tested this way, for the next one I will try my new integrating sphere :-) )

Note that the output is an out-of-the-reflector measurement, so less light is measured compared to bare led measurements (15%? depending on the reflector, in any case: for all my 3535-size led measurements in the past I have used one and the same reflector).

Note also that I did the usual calculation to convert ceiling bounce lux-numbers into lumens, but for colour leds these lumen numbers are not something to rely on because the cheap lux-meters we use are probably increasingly inaccurate when going farther away from the center of the visible spectrum. so especially the red and blue lumen numbers are doubtful. This means that although the shapes and trends (like at which current the output tops out) in the graphs are as accurate as for white leds, the absolute lumens I trust much less.

On top of all this uncertainty, I find the output of the green led unexpectedly on the low side. In fact, I tested the green die of the XML-colour better than the green XP-E2, even though the XML-colour has an 'older' type striped green die (the xpe2 blue and green dies are dotted, like the white xpe2 leds). I guess this is real, but there's always a small chance that the reflow did not go well (not enough solder under the thermal path), or perhaps the led was a bad one, who knows, I'm not going to redo the test, this will have to do.

Here's the graph, I hope it is useful to some of you :-) . For comparison, I included the red XP-E2 results that I already posted about earlier:

Thanks for this

Thanks djozz. Do you have any idea where you would use the blue led. I have a red one in a C12 and it sorta weirds me out when walking with it.

the blue ? on your dashboard on strobe on the highway by night ? 0:)

Not sure where the blue led comes in handy, I have no use for any of these colour leds exept that I find them huge fun. Teleponeman told me that he likes green leds for hunting, while others use red leds. But blue I don't know.

(I used the red light from my xml-colour flashlight succesfully a few months ago as a safelight in the darkroom I made for a photo-project at the school I'm working in, it worked very well: good visibilty while the photographic paper was hardly sensitive to it.)

Blue is good for blood tracking, wether in your hunting gear or first aid /trauma kit for finding the source of wounds.

Also, blue (especially royal blue) makes many things fluoresce without the hazards of UV.

thanks for the results ,I hope intl-outdoor will get the rest colors soon

Yesterday I took my Red XP-E2 in use. I had to delay putting it in use due to the contest build. But now im back to normal modding. I have no idea what to use the red emitter for. Buts its a good amount of red at 2,5A. ;)

Thank you so much for doing these tests. Makes it so much easier for everybody to know how hard we want to push the various emitters and what to expect in terms of output. Not that I plan to order these from Cutter, but its interesting to see. :)

oh.. thanks to MRsDNF`s wife too. :D We love her. :love:


thanks again for these tests djozz. and yes it would be great if intl-outdoor could sell these colours on noctigons!

This is the second thread that has mentioned MRSDNF. I'm not sure what is going on here. She is a terrific women to her kids and she loves them more than anything else in this universe. Anyway I'll pass your message on.

I find those results vary strange, because there is so much difference between the XP-Es and the XP-E2s, and the XP-E graphs are far from other output graphs I have seen. Is it really possible to generate so much light at 0.1 A, or does that violate the conservation of energy?

Question about the red XP-E2:

Why does the red E2 die have lines like a 1st generation die but both the blue and green E2’s have 2nd gen die’s (with dots)?

Edit: half asleep, NVM.

On another note I find it interesting that the red LED did so much better then the green LED, it has always been my understanding green was the more efficient one, part of the reason being that the human eye is better at picking up green light vs red.

Have you experience those uses of the Blue? I have read a lot on this matter and that seems to be the answere all over. However on CPF some people said they used Blue in the above mentioned situations and was not useful at all.

According to the datasheets:

Blue M3 - 45.7lumens @ 350mA
Red P3 - 73.9lumens @ 350mA
Green R2 - 114lumens @ 350mA

What is very interesting how the tests shows Blue being the brightest then Red and then Green, quite the opposite to the specs I wrote above from the CREE datasheets. However that order it best observed at 2A rather than 350mA, 2A not being a current which CREE would recommend. At 1A it would be another order Blue the brightest, Red and Green Equal.
Maybe the response of the lightmeter is different for these pure color LEDs.

Just want to share these pic’s here in this thread to

Red and green XP-E2’s dedomed threw an aspheric (blue is XT-E) unknown current (ramping UI)

Red 1.8A

Full power (1.8A each)

Yes sir, of course they would say that lol. It’s not like magic or like a fluorescent material that’s going to glow, I’ve explained it before… Its hard to describe, it’s like a bright dark hole if that makes and sense. Since the colors we see are light reflected back and there’s no red light to reflect back off blood when using a blue LED you don’t see red but the blue light makes the blood shine nice and bright so its like a bright shiny dark spot.

Ive used it hunting quite a bit and also used one last summer when two of my dogs got in a really really bad fight and I needed to clean all the blood out of the yard, I can tell you from personal experience, this isn’t just something that should work based on theory, it really does work and quite well.

I know this is an old thread, but valuable none-the-less! Thanx djozz! Couple of Q's:

  • I know you have a much better light meter than most of us, not sure what meter you used to do these tests?
  • with my cheap meter, I definitely measured green brighter than red with both XML color LED's and XP-E2's. Any chance you can re-visit the green test?

Fyi... First I ordered color XP-E2's from DigiKey, the realized later these are bin rated, and Mouser has better ones Frown. So, I ordered various top bin color XP-E2's from Mouser and just got them in. The bin specs were quite good:

Red - P3 (same as DigiKey, same as yours)

Blue - M3 (Mouser - same as your)

Green - R3 (Mouser - 1 up from yours)

Royal Blue - 37 (Mouser - whatever this bin means)

Red-Orange - Q4 (Mouser)

Amber - Q4 (Mouser)

I mounted a green R3 and red-orange Q4 on 16 mm Noctigons and built up pills for a UF-1504 to run at 2.48A (6*350mA 7135 + 1 380mA 7135). My intention is max throw. Measuring with my $35 light meter, I got the following for lumens in full flood, throw in full zoom-in:

Green R3 in UF-1405, 2.48A: 211 lumens (@30 secs), 160 kcd (800 meters)

Red-Orange Q4 in UF-1405, 2.48A: 119 lumens (@30 secs), 85 kcd (583 meters)

The lumens are pretty low - could be the poor aspheric flood mode of the light/lens, not sure...

In use outdoors, the green in full zoom is like a laser beam, while the red-orange's beam can hardly be made out. Lighting up a tree about 80 meters away though, the red-orange looks pretty darn bright compared to the green, maybe about the same (double the kcd though isn't much difference). Also note the red-orange looks pretty much exactly like red I've seen on other LED's/flashlights - I could not tell the difference. The red-orange's dye looks exactly like a red dye in both color and having the lines on it (like a XP-E/XM-L, etc.).

The cheap spare pills available for the 1405's is great by the way for testing/comparing. I bought 2 UF-1405 hosts and 2 spare aluminum pills from GearBest. The pills were $1.50 when I ordered - now see them listed at $2.50 (should have ordered more). The aluminum pills fit great and actually have more threads than the brass stock ones.

In the 1504, running a red XP-E2 P3 at 2.4A, I was able to see with my naked eye objects at 400 yards. I tested the green too but I hate using green to hunt so I don’t even recall how well it did. Green seems to be affected so much more by fog and moisture and dust.

Updated my posted with throw distances. Ok - cool! Glad to hear you have a red in a 1504. Practical use/results right now seems to be the best - not sure how red's are handled in my light meter. I thought the red looked better outdoors than on my meter.

I'm using the green just for kicks - freaks people out when you shine it in the sky where there's always 1-2 planes in our area. It's hard to convince them it's not a laser.

Have you de-domed a red or any color XP-E2? Wondering if they come out same way as the whites - better throw, less lumens. Can't recall seeing it posted.