So I bought some LEDs... (part le deux)

[fyrstormer]

...because I heard the Luxeon line was being discontinued, and at least the one place I looked didn't have any Rebels in a similar format, brightness, or power-handling capacity, so I figured I'd better grab a few while I still could. You know...just in case.

I really like Luxeons.

So what's the deal with Rebels? I didn't see any that could handle more than ~500mA or were rated higher than ~80lm. Is Philips bailing out of the high-power single-emitter market? The Rebels all look like they're intended for use in unfocused arrays. Given my experience with putting a Luxeon K2 in my Arc6, the Luxeon line is just as effective as anything Cree or SSC has to offer; they can't be getting burned that badly by market competition...are they?

 

[was.lost.but.now.found]

I really like Luxeons.

I'll bet you miss Beta tapes also. The market really missed out when VHS took over.

 

[asdalton]

Given my experience with putting a Luxeon K2 in my Arc6, the Luxeon line is just as effective as anything Cree or SSC has to offer

 

[yellow]

they can't be getting burned that badly by market competition...are they?

really, I wonder if that is a troll thread, or not
:thinking:
anyone knows what output an XR-E gives at 1500 mA?
or, better, what current it might need for 250 datasheet lumen, like stated in that order paper for the led?
or what current an XP-G needs for 250 lumen?

all that money
btw.: those prices for led - 3-4 years old like the "V" - they are not very good.

 

[fyrstormer]

Luxeons are just as bright as contemporary Cree and SSC emitters, with a higher CRI than both, they just need a bit more power to do it. They tolerate overdriving much better than SSC emitters do, to boot. Flashaholics might have been infatuated with Cree's higher output-per-watt and higher output-per-dollar to begin with, but now that every light on the market is way too bright for anything but foot-candle drag racing, people are starting to remember how nice it is to have a beam that fully illuminates what it's aimed at.

But as has been mentioned many times before, flashlights are a small minority of the LED market as a whole, and I guess Philips thinks the future is lots of tiny, redundant emitters. I guess they aren't wrong, but it's sad to see them discontinue the original line of high-power emitters. There's gotta be more uses for them than just pocket rockets.

 

[fyrstormer]

really, I wonder if that is a troll thread, or not

Oh don't worry, it's not a troll thread. This isn't the first time I've casually made a remark that other people thought was outrageous, but I'm just saying it because I think it's true.

btw.: those prices for led - 3-4 years old like the "V" - they are not very good.

The cyan ones were expensive, because the place only had a couple dozen left in-stock, but the rest were pretty cheap.

anyone knows what output an XR-E gives at 1500 mA?
or, better, what current it might need for 250 datasheet lumen, like stated in that order paper for the led?
or what current an XP-G needs for 250 lumen?

Copped from the K2 TFFC datasheet:

I couldn't find a similarly-comprehensive listing for Cree XR-E's (which is the only valid comparison, since the XP-G is about a year newer than the K2), but from what I could divine, the Q5 was are rated up to ~230lm @ 3.7v x 1.0A, which is about on-par with the cool-white Luxeon K2. And the K2 still has a higher CRI rating than the Q5.

 

[mds82]

wow.... thats a lot of money for not many LED's....

 

[fyrstormer]

Well, it's 19 of 'em, and they're all the brightest in their categories that I could find, so it's not that bad. I could've gotten better prices if I'd bought them by the reel, but that's WAY more than I will ever use. This is just a stash in case I come across any worthy SSC- or Luxeon-based lights in the future that could use a good upgrade, since these may well be the penultimate version that's compatible with the optics on older lights, what with everyone switching to the new small-footprint emitters. I don't want to have to mess with focal lengths if I don't have to.

 

[blasterman]

Is somebody practicing April 1 posts?

Seriously fyrstormer, I just completed a interiour lighting project with a mix of Rebels and Crees from LedSupply, and the $6 neutral white rebels I got put out 100lumens at 350mA, and those were mediocre flux. They put out 180 lumens at 700mA, so how much do your LuxIIIs put out again?

Some of the posted specs you have for colored Lux IIIs and V's get their nads handed to them by the stuff I'm buying from BestHongKong, which, you guessed it, is why I no longer buy Luxeons.

While the K2 has respectable current handling specs it was rendered totally obsolete by the XP-G, and Phillips knows it.

But then again, if you think a cool white Lux III has great color there's no point arguing with you.

 

[fyrstormer]

Is somebody practicing April 1 posts?

No.

Seriously fyrstormer, I just completed a interiour lighting project with a mix of Rebels and Crees from LedSupply, and the $6 neutral white rebels I got put out 100lumens at 350mA, and those were mediocre flux. They put out 180 lumens at 700mA, so how much do your LuxIIIs put out again?

You'll notice I didn't buy any white Lux3's. The whites are all K2's, and the neutral-white ones I got come out at 150-170lm @ 700mA, and they were $4.50 apiece. I'm not surprised the Rebels can achieve better flux per watt, being newer, but again, not the same overall output, hence the dismay that their line of LEDs that can reach that output are being discontinued.

Some of the posted specs you have for colored Lux IIIs and V's get their nads handed to them by the stuff I'm buying from BestHongKong, which, you guessed it, is why I no longer buy Luxeons.

Oh well. Live and learn. But like I said, I really like Luxeons.

While the K2 has respectable current handling specs it was rendered totally obsolete by the XP-G, and Phillips knows it.

I guess. But why they're giving up on the single-unit high-power form factor entirely, I don't understand.

But then again, if you think a cool white Lux III has great color there's no point arguing with you.

Only the single-colors are Lux3's and Lux5's, and as I'm sure you're aware, tint is a complete non-issue with single-colors -- or rather, if you're making an issue of it, you're setting yourself up for disappointment.

- - -

For reference, here is a picture of the neutral-white K2 in my Arc6, next to a Cree XP-E R2 in a Lummi Raw and an OSRAM Golden Dragon. Ignoring brightness, since the Raw is direct-drive and so there's no guarantee it's pulling the same current (though the batteries were all fresh), tell me which has the best tint.

 

[spencer]

Your first thread was closed for a reason. I don't know why you reposted but this thread definitely seems like a troll/advertisement.

 

[John_Galt]

I suppose you had your reasons, but, really, newer LED's from Cree and SSc have replaced Luxeons for a reason.

I mean, if you had a few light that used Luxeons, or had a light that has shown to work well with a K2, I could see buying a few for future projects, but, come on... $180+ for outdated LED's? When Cree's are $3-5? I just don't understand your logic.

 

[Th232]

I couldn't find a similarly-comprehensive listing for Cree XR-E's (which is the only valid comparison, since the XP-G is about a year newer than the K2)...

I think this is kinda the problem here, you're comparing two LEDs from a certain timeframe, and then based on those results extrapolating to say that Luxeons are still as bright. While they were sort of comparable then, you're ignoring advances in technology since then (namely by Cree), which is where your logic breaks down.

As for colour rendition, I think that's one area that we can partially agree on, but that still heavily depends on what tint bins you get.

For the record, from Cree's datasheets, a Q5 is ~240-256 lumens at 1 A, if my counting system is right.

Out of curiosity, how do you think that a Luxeon fully illuminates something that a Cree or SSC doesn't? From what I can see, that's mostly a matter of optics and output, the former can be changed easily for a wider optic, and the Luxeons are getting stomped on in the output arena. An XR-E might have a tighter beam distribution, but the XP-G pretty much has a Lambertian distribution, and greater output.

 

[fyrstormer]

I suppose you had your reasons, but, really, newer LED's from Cree and SSc have replaced Luxeons for a reason.

I mean, if you had a few light that used Luxeons, or had a light that has shown to work well with a K2, I could see buying a few for future projects, but, come on... $180+ for outdated LED's? When Cree's are $3-5? I just don't understand your logic.

As it happens, I do have a bunch of lights using SSC LEDs now, and there are plenty of older lights with Lux3's in them that could use an upgrade. Since Cree can't seem to get their heads on straight about making LEDs with standard lambertian dispersion patterns (probably because that makes them better candidates for household area lighting without needing bulky optics), that rules them out as an upgrade path for lights with "normal" reflectors. Meanwhile, SSC uses a phosphor formulation that is very sensitive to overheating, hence why the Arc6 has an advisory that the highest setting should only be used sparingly. Now my Arc6 can run on Level 7 until the battery gives out without any ill effect to the emitter.

Frankly, I just haven't seen a beam from a Cree light that was as pleasing to look at as what I've seen from the K2. I have the same complaint about Cree LEDs as I have about cheap fluorescent lightbulbs -- the brightness in just a few colors of the spectrum, combined with almost complete darkness throughout the rest of it, makes my eyes hurt. I have a halogen lamp sitting on my office desk for that very reason -- to fill in the gaps in the spectrum so I don't get a splitting headache every single day from the combination of cheap fluorescent bulbs and my computer screen. The K2 has a much better phosphor formulation in that regard. The Rebel might eventually replace it as being just as bright, but not yet, and it's the wrong size to upgrade older lights with anyway.

Once again, the K2s I bought were $4.50 apiece. That pricing is competitive with what Crees cost from wherever it is you buy them.

 

[spencer]

the Arc6 has an advisory that the highest setting should only be used sparingly. Now my Arc6 can run on Level 7 until the battery gives out without any ill effect to the emitter.

Now all your logic is gone. I don't know anything about the Arc 6 but I can make the assumption that it uses a constant current driver.
Say level 7 is 700mA. With a SSC lets say thats 150 otf lumens. A Luxeon at 700mA would be lucky to get 100.
Say level 6 is 500mA. A SSC is still brighter than the Luxeon at level 7.

Just cause you want to run your light at max power doesn't mean it will be as bright as it can be.

 

[Th232]

Since Cree can't seem to get their heads on straight about making LEDs with standard lambertian dispersion patterns (probably because that makes them better candidates for household area lighting without needing bulky optics), that rules them out as an upgrade path for lights with "normal" reflectors.

Come again?

http://www.candlepowerforums.com/vb/showpost.php?p=3192876&postcount=630

 

[fyrstormer]

I think this is kinda the problem here, you're comparing two LEDs from a certain timeframe, and then based on those results extrapolating to say that Luxeons are still as bright. While they were sort of comparable then, you're ignoring advances in technology since then (namely by Cree), which is where your logic breaks down.

I never said the K2 is just as bright as newer Cree emitters -- I said the newer Cree emitters are invalid for comparing directly against the K2, and the newer small-footprint emitters won't work in older lights with reflectors designed for larger emitters.

As for colour rendition, I think that's one area that we can partially agree on, but that still heavily depends on what tint bins you get.

Not really. CRI is based on how accurately an emitter renders a test color pattern as compared to a hot-black-body light at the same temperature. CRI is an issue of spectrum fullness, not spectrum balance.

For the record, from Cree's datasheets, a Q5 is ~240-256 lumens at 1 A, if my counting system is right.

Maybe so, but they get it by using cheaper phosphors, hence why every Cree I've ever seen has a greenish fluorescent tint to it. Occasionally I see one with a snow-white tint, and that's much nicer, but the green-white tint gives me a headache. And anyway, the brightest Luxeon K2 is their neutral-white emitter, not their cool-white emitter. Cree couldn't beat that at the time, and as far as I've seen, they still can't.

Out of curiosity, how do you think that a Luxeon fully illuminates something that a Cree or SSC doesn't?

I'm not talking about beam dispersion, I'm talking about CRI. See above.

the XP-G pretty much has a Lambertian distribution, and greater output.

Well, that's better, but why do the newer Crees still have rings when you put them in normal reflectors? Personally, I can't decide whether they're doing it to narrow the beam because they think they think a tighter beam is more useful, or to artificially generate a market for Cree-specific optics.

 

[fyrstormer]

Now all your logic is gone. I don't know anything about the Arc 6 but I can make the assumption that it uses a constant current driver.
Say level 7 is 700mA. With a SSC lets say thats 150 otf lumens. A Luxeon at 700mA would be lucky to get 100.
Say level 6 is 500mA. A SSC is still brighter than the Luxeon at level 7.

Just cause you want to run your light at max power doesn't mean it will be as bright as it can be.

Level 7 on an Arc6 is 1400mA. A Cree running at that current will blue-shift, and an SSC P4 will burn its phosphor in a few hundred hours at that current.

Also, based on the datasheet which I provided, the K2 I installed in my Arc6 matches the SSC P4's output of 150lm @ 700mA, and it does it with a warmer tint and higher CRI.

Say what you want about my logic, but at least I know the background info about my examples. Where are you getting your numbers from?

 

[fyrstormer]

Come again?

http://www.candlepowerforums.com/vb/showpost.php?p=3192876&postcount=630

Well, good. It's about time they got with the program. I won't argue about beam-dispersion patterns anymore, except perhaps as applies to retrofitting older lights with newer emitters, which is the intended purpose of my purchase.

 

[DM51]

Your first thread was closed for a reason. I don't know why you reposted

This thread can continue if it remains within the Rules.