Q3J 1W vs. TWAK Lux III

With all the talk about the Lux IIIs lately, I though I'd take a minute to share this. In the photo are two Arc LSs @ 667mA with the Fraen LP optics. The one on the left is a 1watt Q3J, the one on the right is a Luxeon III TWAK.




I was kinda suprised about how similar (nearly identical) they were. I was also quite pleased, since I have some more of these Q3Js on hand. /ubbthreads/images/graemlins/smile.gif

Knowing there's more important things to do with a light than shine it at the wall, I took them both outside and took a little walk, lighting up various things as I went. Here too, I could detect virtually no difference between the two. Sometimes I thought the TWAK might be a little brighter, but I'm not convinced that it just wasn't my brain telling me that it should be. At any rate, I have some new found love for my trusty Q3Js. /ubbthreads/images/graemlins/smile.gif

Just an interesting (to me anyway) observation that I thought I'd share. /ubbthreads/images/graemlins/grin.gif


Peter

NICE

thanks for the beamshot.

I think the similarity between the two is because:
1. lux lottery
2. bec the lux3 is driven at lower drive (underdriven) that it ought to be.

Well, i think your beamshot might help explain why gransee goes with 1W lux than with 3W in his ARC4. /ubbthreads/images/graemlins/smile.gif

again, thanks for sharing this excellent beamshot for us

Peter, I don't think the LIII will be any brighter if it is compared to a Q3J running the same current. Where the LIII's really perform well is in a light that can supply 1A or maybe a little more (I'm conservative). You will notice quite a difference between a Lux at 667mA and a LIII at 1A or more. I have one LIII in a 3C configuration with 0.5 ohms, running off NiMH cells that blows away any of my 1 watt LS lights.
Rob

Litfuse: Did you notice any diference in the heat output? My Lux 3 TWAK driven at 750mA puts out much less heat than my R2H at 500mA. But i have them in different hosts, PR-T and regular McLux bezel respectively, so i dont know if this is also a factor. Brightness seems pretty close too.

P.S. Don't get me wrong, I really like those Q3J's. When Kong was selling them for $9.50 or so, I picked up 9 or 10 of them, put them in a TL2 LED, LSH-s, a few mini-mags with ZLT, and a KL1. They are all bright and white, but still don't quite match up to the LIII's that are driven harder.
Rob

yep

lux3 will shine more if it was driven above 700 mA (and more if it was driven at 1 amp or higher).

As the Vf of Lux3 and 1W is near the same, driving at same current which give the same power output. Also good bin of 1W vs Lux3 underdriven. If this account for the similar brightness.
then the only difference of Lux3 is that can driven at higher current??

[ QUOTE ]
Xminxm said:As the Vf of Lux3 and 1W is near the same, driving at same current which give the same power output. Also good bin of 1W vs Lux3 underdriven. If this account for the similar brightness.then the only difference of Lux3 is that can driven at higher current??

[/ QUOTE ]
In summary, here's the way I understand these Luxeons:
(Corresponding bin numbers being equivalent to each other)
Both the 1 watt and the 3 watt driven at say,..700mA should have about the same Original brightness....BUT.

The 3 watt running at 700mA will be superior in maintaining it's Original brightness over many 1000s of hours. It's designed for that 700mA+ current.

The 1 watt, driven at the same 700mA will lose some of it's original brightness after only a few hundreds of hours of operation, because it's only really rated to be driven at 350mA.

Lumileds claims that running at proper specification will result in good "luminance maintenance". /ubbthreads/images/graemlins/icon15.gif

I can tell from the picture the TWAK is slightly brighter...

I think it was discussed that "S" LuxIIs would be equal to "Q" 1Watters whereas "T" LuxIII would be to "R"s - and the datasheets of Lumileds seem to indicate this as well according to CMs math he did on the subject.

The appearance of 2 single Luxeons might still pretty much depend on the Luxeon lottery and the used measurement instrument as well - the sample size is quite small too.

No personnel experience with "R"s and "T"s yet though

Klaus

Thanks for all the feedback guys. I guess the point I was trying to make is that everyone seems to be all (overly?) hyped up on the LuxIIIs and seem to forget that the nicely binned 1Ws are still an excellent choice for many applications. (I wish I could find either /ubbthreads/images/graemlins/frown.gif ) I've been doing some Arc LS mods, and nobody seems to think the Q3J is "good enough" any more, everybody wants a LuxIII. Oh well, you gotta give the people what they want I guess.

I was aware that the IIIs really come into their element at the higher current levels and also have a *rated* lifetime at those higher specs. This is great news! I really like how the IIIs seem to be much more consistent in their binning and all the white bins seem to actually be *white* with only subtle differences between them. Could it be that the "Lux lottery" is on the way out? I sure hope so! /ubbthreads/images/graemlins/smile.gif

As far as the lifespan of a 1W vs. the Lux IIIs goes, I really don't see this as an issue. I don't think any "flashaholic" is ever really going to see the "end days" of either because there is always something better coming around the corner. The bins keep getting brighter and better, and everyone wants to be on the cutting edge.


[ QUOTE ]
kakster said:

Litfuse: Did you notice any diference in the heat output? My Lux 3 TWAK driven at 750mA puts out much less heat than my R2H at 500mA. But i have them in different hosts, PR-T and regular McLux bezel respectively, so i dont know if this is also a factor. Brightness seems pretty close too.

[/ QUOTE ]

kakster I'm seeing just the opposite in regard to temperature. After 15 min. on a tiled countertop the TWAK @667mA was 130F, while the Q3J @ 667mA was 101F, quite a difference. Can anyone offer an explanation for this difference. Is it a result of the Q3J's lower vf? /ubbthreads/images/graemlins/thinking.gif

Peter

Interesting thread. It just so happens that I am in the middle of my first mod which is a arc ls and have been pouring through the threads trying to figure out what emitter to put in it and how high to pump up the current. If I understand correctly I would not be gaining anything by putting in a TWAK emitter?(if I could find one)and running it at 600-700ma?

If you got a TWAK you would have a nice white beam for sure, but I don't know that you'd see much (if any) increase in brightness over a Q or R binned 1W. 600-700mA is a good range to get maximum brightness with decent runtime, while keeping the heat manageable. Many would even say 500mA is a better option for a light that will see actual "task" use. You don't see a dramatic increase in brightness with a 100mA increase in current. Things look mostly the same, but you're using your battery up faster. If you want a "show-off" light, drop in a TWAK and run it (in short bursts) at 1A! /ubbthreads/images/graemlins/cool.gif


Peter

The TWAK's are nice. I still prefer the light of the Q3J. I have small stash that I've set aside for personal lights and prefer to use those rather than any of the 3W's. As far as brightness goes, I can't tell the difference between a Q3J and a T or S binned 3W. Not in a regulated light anyway. The difference in brightness is less of a factor to me than the color of the light. When people ask me this question of 1W (Q3J) vs. 3W, I usually advise them to choose according to the color of the light emitted, rather than brightness. I think that brightness is not an issue, especially in regulated lights.

Actually, I have to say that the TVOK's that I've seen have been very nice. I'm just not wild about blue tint. I prefer the warmer lights. I typically use my lights outdoors and find that the cooler lights don't do as well.

@Tony-Interesting comment on the TVOK....
As you've noticed, I've got one of the TVOK...but as far as tint goes, it leans a tiny bit on the Yellow (warm) side-without even a hint of any blue at all. The Luxeon lottery still lives. /ubbthreads/images/graemlins/tongue.gif

It's like the Q3J that you sold me awhile back, except that it's color is perfectly uniform from the outer corona to the dead center of it's beam.

BTW-is the LP Fraen optic supposed to give a pinpoint spot?? I just tried one with a high dome tonite, and all I see is a very large, intense spot--with practically NO side spill. /ubbthreads/images/graemlins/rolleyes.gif

--Is this normal? /ubbthreads/images/graemlins/confused.gif

chop, i agree with you.
Twak is indeed nice, but for general use, comparing TWAK to Q3J when Q3J is at almost half the price, it is a lot made more sense to choose Q3J over it. that is because Q3J has better color, in general. It is also not much difference in brightness. If you run it at or below 700 mA, i bet your eyes cannot even see which one is brighter.

regarding the color. I personally like cooler color than warmer, but i love the whiteness of Q3J than the blueness of TWAK. But i agree with you, chop. It seems like the warmer light is better performer outside than the cooler one. /ubbthreads/images/graemlins/icon3.gif

Chop, I read your comments with interest because I've found pretty much the opposite with outdoor lights, that I tend to see better with cooler colors. My favorite walking light uses a Q-bin low dome with distinct blue cast; I seem able to see the outlines of objects more distinctly using that color, for some reason. Because of this, I can usually make out objects farther away... in other words, not just see them, but identify them.

But I suspect the relative effectiveness of various colors is at least partially a personal matter. Few of us are likely to have perfectly tuned "light detectors" (eyes) that see all wavelengths equally well. In reality, even if we can see all the colors (15% of males can't even do that, right?), I doubt that we see them equally well, and this probably has something to do with the color we prefer for use outdoors, or in any unfamiliar environment.

Just my two cents. /ubbthreads/images/graemlins/grin.gif

vcal,

I may have composed my last post badly. I was saying that I like the TVOK because it didn't have any blue in it. I LIKE the warmer colors, as long as it isn't green.

What you're getting with the Fraen LP is right on. All hotspot with no sidespill. The Fraen LP does turn most lights into throwing performers, but I still prefer the good ole NX05 for all around use, that is of course, when I can't use a reflector.

A well tuned, large reflector rules! /ubbthreads/images/graemlins/buttrock.gif

NX05 is a great all-around optic, kind of like all weather tires on a car: competent at everything, the best at nothing.

Fraen LP throws farthest of the small optics, but IMHO none of the small optics can compete with either a 30mm optic or a well-designed reflector.

(Sorry this is off-topic.)

milkyspit,

Your post brings me back to my point. Don't chose one over the other based on brightness. I think that the color of the light is a personal preference (or need) and should rank higher than brightness when choosing an LED.

Of course, all things being equal, I'll take the brighter one, whether it's a 1W or 3W. If I had to choose between a brighter LED with a blue tint and an LED that is a little less bright, but has better color (for me), I'll take the one with the better color.