R5 or Q5?

[Rusty Joe]

I have gotten into budget lights lately, esepcially the zoomables, and I so love them. I notice ebay and a lot of the budget light retailers have Q5 lights. I have a few in my collection now, but I've also seen just a few R5s available. Can someone tell me the difference between these emitters? And which of the two is better? Why are there so many more of the former instead of the latter?

 

[ProstheticHead]

The LetterNumber code on the Cree LED emitters essentially tells you the efficiency of the LED. Efficiency increases with later letters in the alphabet (i.e. RX is better than QX) and higher numbers (R5 is better than R2). There are QX rated grades (bins) available for different emitter types. XR-E, XP-E, XP-G are the types I've seen in a lot of budget Cree lights on ebay available in Q5 bin. R5 isn't available in the old, less efficient XR-E emitters.

So 1 line answer: R5 will likely be a better LED than Q5.

A more efficient emitter could mean a combination of more light or longer battery life, although that doesn't tell you anything about the rest of the torch which can effect both of these.

Hope that helps.

 

[JacobJones]

I assume when you say R5 you are talking about XPG's but a Q5 could be an XRE or an XPE. XRE's and XPE's have smaller dies than an XPG and therefore throw further. XPG's have larger dies and more output yet they don't throw as far. There are more XRE's and XPE's used in budget (the bottom end of budget) lights because they are cheap, XPG's are uses in expensive lights and more expensive budget lights to get more lumens.

Hopefully this is clear enough, if I've made any mistakes blame my tiredness, goodnight

Edit: neither of the LEDs are superior, they each excel at their specific applications

 

[jupello]

The R5 and Q5 tell how efficient those Cree LED's are.
Later letter in the alphabet means more efficient emitter. The number after the letter does the same thing, but only to differentiate the emitters that are marked with the same letter.
So R5 is more efficient than Q5. There's also some physical differences between those LED's, the Q5 one is most likely XR-E, and R5 is XP-G.

 

[Rusty Joe]

Thanks, all. That tells me something. I have a 1xAA and 3xAAA and they are Q5s and one of those is an XR-E, I believe. I love them because they seem to put out more light, or at least work with the zoom feature to enhance throw. I can't tell, but I seem to be able to see much more with them (though I've gotten my share of duds ordering those cheap Chinese things, too).

I just can't believe in the quest for infinite lumens that I find myself happy with a 1xAA light! I think it has everything to do, as said, about the beam density from smaller dies. I'm still looking to learn more about the technical aspect of these things.

 

[yifu]

Those are bin numbers. The XP-Es only officially goes up to the R2 bin, so the R5s must be XP-Gs. Looking at the Cree datasheet, a R5 bin should be producing around 137 lumens/watt. The XPG is the better emitter as it can be driven to produce 492 emitter lumens compared to the 200+ of the XP-Es. The newest LED from Cree is the XM-L and that goest up to the U2 bin, producing more than 160 lumens/watt and capable of 1000 lumens max.