Lux V Vs Lux III ??????????

I have a question among you guys, LED master (or more experienced LED user).
I compared my lux V (WX1T i believe), driven with BB (not sure drive current, most likely 500 or 667 mA) against my lux III (TWOK for sure), driven with 1 amps driver and i noticed something weird.
Both of them register approximately similar overall light output. the lux III has 1.40 lux while the lux V has 1.41~1.42 lux. Does the result is as expected?
(oh btw, overall meaning the ceiling bounce test, which explains why the reading is very low )

I measure the current draw from lithium R battery and got the following reading:

lux III driver drains ~1.2 amps while the lux V BB drains ~2 amps.


based on the readings,, what would be the point of using lux V then? It drains more power, gives flood beam and only a tiny bit more output. Is there something i am missing here?

assume the BB has 65% ~70% eff (since 3.6 V in, 6.7 Vout) which result in current out 700 mA, approx. The lux V should put out about 140 lumens.

now, assume the other driver is a linear driver (which it should be, at this input). So the lux III is driven at about 1.2 amps.
that makes it output 87 * 1.2 (approximate number for 1.2 amp drive compared to 700 mA) = 104 lumens?

I am sure my assumption might be off, but the W should perform at least 1.5 times better than the overdriven lux III right?

i am not sure if i am clear enough, but it is a tiring day so

thanks for the help beforehand, anyhow

Hrmm... well, the only Lux V light I've ever owned was a Space Needle II clone and though it obviously didn't have the throw of a Lux III Mag Mod, it definately put out more total light than a direct drive Lux III. Of course that was before I had a U binned Mag Mod but I still think that the V was brighter overall.

Current regulation is good, but it often won't show the real 'few seconds at a time' potential of an emitter.

A lux V at 500-667 mA i would expect is in the 3.1 to 4.4W of output range.. i would expect about 60-90 lumen of output..

A lux III at 1000 mA is typically about 3.7W and 75 lumen... as you can see.. pretty close to the same.

looking at the lumiled datasheet for the V.. it says 6.84 typical voltage at 700mA.. 4.78W.. and 120lumen at that level of drive.. at 500mA it shows 75% of the output of 700mA so that'd be 90 lumen. you are also only putting about 3 1/4W through the emitter at 500mA. (lux V).

now.. looking at the Lux3... at 1000 mA.. you are putting 3.5-3.7W through the emitter.. a T bin should get you 80+ lumen at that drive level.. so basically.. a bit of apples and oranges comparison here... you'd need to get actual current and voltage at the emitters to get a better handle on the situation..

What is the battery voltage and do you have high enough Vbat to maintain regulation? A good starting question.

The lux V and lux 3 are very similar in lumen per watt.. so if you put about the same power into them as you are, you'll get a very simlar light out of them which you are..

with the V, you can put more power through it so more lumen in a smaller space.. if you aren't taking advantage of that, there is not much call for a V emitter.

The 'W' ranking of brightness is binning at 700mA which will net you about 4.8W.. Lux3s are binned at 700mA so the 'lumen' bin will seem a lot lower.. because it's a lot less power.. howerver.. at 1000mA.. lux 3 is rated 80 lumen... but at 3.9V.. so 3.9W..

My basic understanding of the luxV is that it's 4 1W emitters in series-parallel configuaration inside the single die... i believe this gets them to be not driven as hard where they have a higher lumen/watt ratio.. example.. using the 3.8/4.8 ratio and comparing 120 lumen rating of the V.. that should make 100 lumen for the lux3 at 1000mA.. but it's only rated 80.

At full drive on the luxV i'm sure you'll be seeing more output than the lux3.. perhaps you actually are overdriving the lux3 to 1.2A.. if that's the case you can easily get well over 100 lumen, and if you underdrive the luxV it's quite likely it will output no more than 100 lumen, again it all seems to make sense that you are over driving the 3 and underdriving the V so they are at the same level.

measuring the ceiling bounce to get 1.4 lux.. it's way too low to get an accurate reading.. you need to hold your light closer to the ceiling or use a shorter ceiling. I usually get readings like 10-20 when i do those sort of tests.

-awr

I don't think the ceiling bounce test is a very accurate way to actually measure total output.

Using my lumen integration technique, I measure the Lux V at 700mA to output about twice what a Lux III at 700mA does.

As well it should.. he's comparing a luxV at 500-600 vs a Lux 3 at 1000.

The ceiling bounce method is only going to be fairly accurate if the spots are fairly close in size (simlar reflectors etc).. i'm sure they aren't terrible for a basic comparison.. when i do tests with lights that are 'supposed to' be 400 lumen for example, their bounce test is very similar.. and when i use a light that mathematically is supposed to be 800 lumen it in-fact ends up close to double... it's a useful test, just not super accurate.

-awr

Thanks for the reply guys

I am sure my ceiling bounce test is not really accurate, per se. But it should be fairly representative of what the actual reading should be. Also, i was using my bathroom, so the room should be fairly small to minimize light loss etc etc (i am babbling )

I guess what i am debating is, why would you use lux V if it is more flood (dont forget the donut hole) and using more power if you can get away with an overdriven lux III that uses 30~35% less power and still produce the same amount of light?

I am sure as the power supplied to the luxes increases, the difference between lux V and lux III will definitely increases. But for argument sake, it does not seem to be a good choice to use lux V in this case, or does it?

bang for buck is the lux3 IMHO.. i would rather spend $30 on a Ubin Lux3 that i can get 110-120 lumen out of vs $35 on a LuxV which i can get 120-140 lumen out of... especially considering the donut hole issue etc.

Now.. i did invent a reflector that could eliminate the donut hole but don't have the time or reason to build one.. I'm thinking that with the K2 around the corner the luxV's days are numbered.

-awr

Don't be so sure on the demise of the Lux V just yet Andrew. Keep in mind, the same advances in Lux / K2 die can go into the Lux V (or K2 equivalent) as well.

There are some cases when the Lux V is just the ticket. At least with my custom optics, the Lux V is a heck of a producer - although I agree - more floodish - but man what a lot of light.

My bench testing indicated that for "similar" optics technology, the Lux V and III have similar "Throw" but the beam is a whole lot larger. At least on my test, the beam donut / residue concerns present at 1 meter were virtually gone at 3 meters - so not really an issue for me. it was sort of like the merging of multi LED/ reflector type lights.

If I were making a 3 x 123 cell light, the Lux V would be high on my list, as relatively simple electronics can make for a very efficient package. Also, the price differential for a premium Lux III and a premium Lux V is getting more and more narrow, while Lux V premium bin availability is on the rise.

I'm thinking.. that with similar power drive and similar light output.. the K2 does have the capability of making the V a moot point.

that said... i finally got to do some testing with the K2s i have on hand and i was pretty underwhelmed by the results... at the same current level they were outputting more light than Tbin emitters but not more than my Ubin emitters.. and more importantly.. they all had higher Vf.. Ms and Ns.. so the power consumption was decidedly more with the K2s.

They are really neat, but If the Vf issue is not resolved by the time they are mainstream.. i think i'll be using Lux3s in the minimighty and/or BAM afterall.

Deleted - sorry.

The Lux V still has life that people haven't explored yet. Very few members use Lux V emitters to make lights and even fewer use the Lux V to its full advantage.

People don't know what they are missing by not using a Lux 5 emitter. I'm finding lots untapped light for the lowly, expensive, and very bright emitters by carefully focusing the emitter. I don't even know if I should use the word expensive; the Lux V is cheap for the amount of light it puts out.

Because of the initial price differences between a Lux III and V most people favored the using and modding the cheaper Lux III. Modders use the little III emitter or clusters of emitters then put them into overdrive to get the power of a Lux V. People have favored quantity of a Lux III over the quality of a Lux V. Since there are more Lux III around and more mods done on a Lux III the modders are more familiar and continue to use it. Most modders have used a Lux III and half-heartedly used Lux V emitters using Lux III parts. Since the quick V mods were not entirely successful and set up of the V emitter is less than optimal the rumors that the Lux V emitter beam is inferior to a smaller Lux III. I've found a Lux V beam to be equal to a Lux III in throw and superior in spill light.

The Lux V emitter is a different beast and most mods done with the V emitter are not showing the Lux V in 'the best light.' To put this thought into other words, people are used to modding small block, Lux III, engines. The similar looking Lux V big block engine is different and should be designed to work differently. Focusing the Lux V to the 'sweet spot' on a reflector is the key to making an economically brilliant light.

The Lux III, because of its smaller point source of light, is more tolerant of sloppy builds. A Lux III that is unfocused is less noticeable. The Lux V is not tolerant of sloppy builds. The Lux V has a larger area that must be focused precisely to its 'sweet spot' on a reflector. Once the sweet spot has been found in the reflector the magic of the Lux V is revealed. A Lux V that is out of focus shows a flood beam easily because the powerful light output exaggerates the problem. A well done Lux V mod is impressive in both brightness and performance. It is worth the trouble to find the sweet spot using a Lux V with a reflector.

Here are two examples of the best of the best in real world conditions. One light is a very white beam Lux III, UX1J, running a Downboy 917 in an Aleph 3 head. It is undoubtedly a killer combination…for a Lux III. The other picture is the Lux V very white beam, XX1S, running at 1000mA in a Surefire Turbo Head. Can you see what a well tuned, big block, Lux V will do? I'll let you guess which picture goes to which emitter. Which light would you want to use to walk the dog at night and spot a lurker in the shadows? Click on the little picture to get a breath taking view of a focused Lux V.

The Lux V is a bright platform with extreme lighting potential that has yet to be fully explored. The Lux V can still dance better than the Lux III…but you have to learn the Lux V dance!

Or I could be tooting out the wrong end!

that's a great post.. there can be no doubt there is a good place for the V.. I still want to take a luxV and put it into a big reflector.. maybe a reverse-pointing emitter pointing toward you into a big dish reflector harnesing all the light coming out... maybe a 4" reflector.. i think that would be a stunning combination and i think the V would be a much better use than the lux3.

-awr

That beam shot is fantastic and makes me consider the Lux V despite its relatively short life. It looks like you used a flash for the picture.

Would you, (TrueBlue) have a comparison between this LUX V and a 10-12w halogen MR type lamp, preferably outside?

I ask because I would like to compare my current bike light to a Lux V, (with a good reflector design) and I have never seen a Lux V.

In a still photo the Lux V spill beam up close is so brilliant that the spill light does look like a camera flash firing. The difference between the Lux III and V are very startling. I'm sorry I can't help with the second request for a halogen light. I'm afraid all the lights around my house and at work have LED emitters except for two of them…a Mini Maglite and an Energizer 2AA "Power Ranger" light that is shaped a lot like a Surefire U2.

I don't know about the limited lifetime of a Lux V because I've haven't used one up yet. I suspect that really overdriving a Lux III would be more harmful to the emitter than a Lux V running closer to specs.

shiftd said:

I guess what i am debating is, why would you use lux V if it is more flood (dont forget the donut hole) and using more power if you can get away with an overdriven lux III that uses 30~35% less power and still produce the same amount of light?

Click to expand...

I think you just said the answer to your own question. With the Lux III, it is an already overdriven solution. You're shortening it's life, and have little to no room for additional drive. Ok, so maybe we can say the Lux V already has a short published life at spec? Maybe, maybe not. TrueBlue says:

TrueBlue said:

I suspect that really overdriving a Lux III would be more harmful to the emitter than a Lux V running closer to specs.

Click to expand...

I think I tend to agree with his opinion. I do not have any hard facts to support this, just my gut feeling.

The other reason for using the Lux V is related to what I just mentioned. The Lux III is already overdriven at this level of output. If you want more, you're out of luck. The Lux V still has a ways to go. You can get more light out of a single Lux V emitter than you can from a Lux III. Sure, you can make a tri- or quad-star out of Lux III, but you'll end up paying more, both in dollars and in "flashlight head real estate" than if you used a Lux V.

quickly i believe becoming a moot point.. the K2 is a 6W emitter, rated at about exactly the same output as the LuxV with better lifespan ratings and heat capability.. i think the V has seen its run.

-awr

I wouldn't throw the Lux V baby out with the bath water just yet.

To match a Lux V, a lot of damaging heat is going to appear as soon as people start overdriving the K2 emitters. There could be some burnt fingers in people's future. I know.

People are going to drive the K2 emitters to the maximum of 1.5A because they can. Some people will overdrive the K2 emitters. I hope people will remember that driving the K2 to higher output will mean they will have to deal with a lot more heat. You'll kill the K2 with enough heat.

I am sticking with the Lux V. I know I'm going against the wind again. I do that a lot.

I have seen what is being made around the world. And I've heard a couple of rumors. The K2 is eclipsed by cooler running but just as bright or brighter emitters. I only have pictures but I do not know how bright or the tint in real life. I'm sorry I can't post the pictures but I promised not to. Don't give up on the overseas emitters yet. You will all know once I get some of the 'other' emitters in hand. Meanwhile, the Lux V is the best we have got.

Maybe Lumileds has heard about the 'other' emitters too. That might be why the K2 emitters are selling cheap. They want to be entrenched in the market before the other emitters hit the streets.

The K2 'Jell-O' dome and the different mounts will be trouble. The K2 is not as revolutionary as Lumileds makes them out to be.

I am not guessing. I know. If you drive the K2 around 1000mA you are safe.

The Lux V driven at specs or higher is brighter. Ask me how I know.

Some S bin 12-K2's would be a different story at 1.5 amps though!
Burnt fingers, lol, I've been there. Left an impression of the slug on my index finger for about a week.

lol...I am guessing you said the same thing I did when we made toast of our fingers...right?

TrueBlue said:

Ask me how I know.

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How you know?