Cree XT-E White announced

[AnAppleSnail]

But XTE has termal resistance 5 C/W, XML 2.5.

XT-E 5 C/W 3.45mm square, 100% rated output at 85C
XP-G 4 C/W 3.45mm square, 88% rated output at 85C
XM-L 2.5 C/W 5mm square, 90% rated output at 85C

Compare the area and rated output at 85C.

 

[SemiMan]

They've tried to make things more realistic - like FourSevens stepping up to the ANSI rating and having their S2 XP-G quarks rated at lower output than the R5-bin lights.

XT-E left, XP-G right. I can't make heads or tails of it. Maybe the XP-G curve is plumper in the middle and lower at the edges though.

Spatial distribution is likely a far-field measurement and hence the source size does not play into it. It gives an indication, but only that, of how it will do in a reflector. However, given that it has that shape and the source size is small, one could guess that perhaps it behaves like a small source and would be better than the XP-G

 

[bshanahan14rulz]

I think the thing to do is figure out if the whole dome, or even the entire "clear" covering, corners and all, lights up, and then figure out an LED that has that same apparent size.

I like when Cree releases new LEDs. I just wish it would affect the prices of the "old" ones more ;-)

 

[saabluster]

I think the thing to do is figure out if the whole dome, or even the entire "clear" covering, corners and all, lights up, and then figure out an LED that has that same apparent size.

I like when Cree releases new LEDs. I just wish it would affect the prices of the "old" ones more ;-)

At least in the "old" XP-E HEW, which is identical to the XT-E from chip up, the dome was perfectly clear. The dome did not contain any phosphor despite some people's comments around here. I ripped the dome off to see for myself.

 

[blasterman]

Looks geared for room lighting systems.

Cree makes power LEDs that aren't geared towards 'room lighting'?

 

[AnAppleSnail]

Cree makes power LEDs that aren't geared towards 'room lighting'?

They make some that work well enough for flashlights.

 

[RoGuE_StreaK]

Any ideas on pricing / availability of these? Seems vaguely comparable to an XP-G but with less output as the current increases, so unless it's significantly cheaper, the XP-G's still better for mine. I think I'd want it to be at least 2/3 the cost. Yeah the voltage/current is slightly less, theoretically you could feed it 1.5A for the entire useable portion of a single lipo, but the XP-G is only slightly affected at the tail end of lipo life, depending on where you set your cutoff voltage.

PS. Where'd that spatial distribution image come from? Seems a lot different to the one on page 9 of the spec sheet? eg. I read 60% output @ 50degrees according to the spec sheet?

 

[darkmilk]

Looks like just under AU $2 each, but the site doesn't specify which bin/tint that is.

 

[RoGuE_StreaK]

Interesting, Cutter has them (as darkmilk said, no bin specified) for about Aus$2 each, as opposed to the XP-G's at $5.50+ each! Have requested a sample, I was going to be tossing up between XP-G's and XM-L's (for "ludicrously bright" option, well, relatively), but these seem reasonably comparable to the XP-G for almost 1/3 of the price, just depends on whether there's enough lumens for my needs; I know, you can never have enough lumens, but considering a Luxeon K2 seemed to almost reach my initial goals, these suckers may well do the trick.

That said, the cost of the LEDs is nothing compared to the rest of the system...

Any thoughts on how these are likely to compare heat-wise? I'm not very good at interpreting the figures to deduce what kind of heat it'll generate.

 

[pretmetled]

Cree makes power LEDs that aren't geared towards 'room lighting'?

Stupid question: Who does make mid-power LEDs that are geared towards room lighting? Since low/mid/high is rather subjective, say 100 - 200 mW per emitter.

 

[AnAppleSnail]

Any thoughts on how these are likely to compare heat-wise? I'm not very good at interpreting the figures to deduce what kind of heat it'll generate.

I suggest "Enough heatsink to keep the LED at 85 C or so." How hard is that? This means that your heatsink has to remain below 75C or so, given LED and MCPCB thermal resistance. That's still a hot heatsink (can be small due to large deltaT), so...look at existing LED arrays, these aren't wildly more or less efficient than existing new Crees.

 

[HumanLumen]

Has anyone (Saabluster??) been able to trial these yet for use in a torch/flashlight (depending on which side of the pond you are from!!)

HL

 

[saabluster]

Has anyone (Saabluster??) been able to trial these yet for use in a torch/flashlight (depending on which side of the pond you are from!!)

HL

I have tried the XP-E HEW which is virtually identical. Good with reflectors but not aspheric lenses unless the beam is diffused.

 

[HumanLumen]

Thanks Saabluster. If I may push the question a little further, would the spot produced by the XPE-HEW be brighter than the XP-G, assuming same current, luminance bin, reflector etc?

Cheers!
HL

 

[Nil Einne]

Why ???

At 700mA an XT-E Neutral puts out 203 Lumens.

At 700mA an XP-G Neutral puts out 213 Lumens.

At 700mA an XM-L Neutral puts out 240 Lumens.

XT-E 5 C/W 3.45mm square, 100% rated output at 85C
XP-G 4 C/W 3.45mm square, 88% rated output at 85C
XM-L 2.5 C/W 5mm square, 90% rated output at 85C

Compare the area and rated output at 85C.

Presuming these 2 posts are accurate (I'm lazy to check) and I didn't screw up, at 700mA and 85C

XT-E neutral 203 lumens
XP-G neutral 187 lumens
XM-L neutral 216 lumens

 

[degarb]

A casual observer--with such a low fvoltage, would these work good on 6 volt, if two XT-E's were used in series with direct drive?


7.6 volts is not easy or very practical, But 6v is--4 AA rechargeables, or one 4.5 amp hour agm. Naturally, one would like no more draw than 400 milliamps, for useful runtimes. Maybe xml is better for 6 volt? (I don't like efficiency drop of drivers; since, with dual led using 4AA direct drive, I could get 200 lumens at same current drive level that my Fenix hp20 uses for 130 lumen. Yes, current drops over time, but with variable resistor, you can lower resistance as time goes on--provided enough over head, but not too much that would pop the led on fresh cells.)

Then with price drop, it would be even more practical of a design.

 

[Bright_Light]

http://www.ledsmagazine.com/press/34300

LEDiL qualifies lenses for use with new Cree XLamp XT-E LED

Date Announced: 18 Feb 2012
LEDiL announces the availability of 33 lenses qualified for use with Cree's new XLamp® XT-E White LED, which Cree promotes as delivering twice the lumens-per-dollar of other LEDs.

 

[RoGuE_StreaK]

I notice that Cutter now has the XT-E White listed for around $3, as opposed to the $2 or so they originally listed them as.

 

[bshanahan14rulz]

the Wiki article on LEDs has some nice diagrams about light extraction. Most of it is common sense, but it's a good visualization at least, and explains what Cree was trying to do with that funky gem top they stuck in thar...

 

[blasterman]

Who does make mid-power LEDs that are geared towards room lighting?

The entire Semi-Conductor industry?