CREE XP-L2 - NEW GENERATION

Hi folks,
CREE recently announced new XP-L2 leds as an upgrade to existing XP-L. It looks like its only marginal upgrade but not. Actually this is the best upgrade ever!

See official page: http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Discrete-Directional/XLamp-XPL2

See datasheet: http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/Data-and-Binning/dsxpl2.pdf

1) LOWER VOLTAGE - VF CURVE
See mi picture where I overlayed both generation. XP-L2 has got lower voltage by 0.1 - 0.2V. In 3A current flowing through the diode there is 3.12V instead of 3.36V, which is even 0.24V. Translated to wattage, its 9.36W to 10.08W, 7.7% improvement.

2) HIGHER EFFECIENCY IN HIGH CURRENTS
See picture. Both generation overlayed on each other. XP-L2 gives 25% more when current is 3000mA. That means amazing difference of 115 lumens just in this. 1265 lumens compared to 1150 lumens, its 10% improvement.



3) HIGHER BINS AVAILABLE
Shortly you could buy 5000K or 4000K color temperatures in V5 bin (460 lumens/1050mA) which wasnt possible anytime before. V4 to V5 is 4.5% improvement.



For me this is amazing upgrade, on high currents total improvements well over 20%. We still do not have exact datas in pct.cree.com application, values were taken from datasheet.

Cool. I wonder if the if there will be an XP-L2 HI too...

xm-l2 is quite old, and when will they upgrade it

Why would they update the XM-L2 when there's the XP-L (and now the XP-L2)?

DIWdiver said:

Why would they update the XM-L2 when there's the XP-L (and now the XP-L2)?

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I dont know, maybe bigger size bigger footprint=> more area for heat go out?

The copper star and the surrounding mass of the flashlight determine the heatsinking.

XPL is kind of like the direct successor to XML, so now they're upgrading it, until they find an even better footprint. Cree has the high output, high footprint designs with the XHP35/50/75, then the high output, small footprint with XPL.

All that is good, but until leds are so sensitive to overheating and require good cooling, we won't see any advance in practical usage. Leds were hot and needed good cooling 10 years ago too, and nothing changed since then. Maybe, size of heatsink being reduced a bit, nothing more.

I couldn't disagree more. Cost has come down a lot, efficacy has gone up a lot, and thus you can get a LOT more light for your buck, in your fixture, for your watt-hour, on a given heatsink, etc. In the past ten years LEDs have gone from a fringe market to mainstream, completely swapping places with incandescents. Practical usage has skyrocketed. What rock have you been living under?

All modern LEDs are specified to operate at 85C/185F for years. And for the past 40 years LED tech has improved exponentially in accordance to Haitz's Law. Though before long we'll be hitting the theoretical lumens per watt limit. Here's hoping quantum dot emitters catch up by then.

Anyway, that Vf curve is a big deal. But you can only take advantage of the lower Vf with a buck regulator. It will be interesting to see if any of the '7135 based lights move to the XP-L2.

This comment is completely ignorant w.r.t. LED technology. I am not sure how you would reach this conclusion with any modern knowledge.

Further to other posters, many will last 10+ years in normal service at 105C or even higher with products designed to excel in high heat. Even well made dirt cheap LEDs will last 50,000+ hours at 85C solder point temp driven at their rated currents. Their efficiency is now well beyond any other practical source whether white or a limited spectrum. We are not talking super expensive LEDs either, we are talking dirt cheap high volume LEDs from major manufacturers.

CuriousOne said:

All that is good, but until leds are so sensitive to overheating and require good cooling, we won't see any advance in practical usage. Leds were hot and needed good cooling 10 years ago too, and nothing changed since then. Maybe, size of heatsink being reduced a bit, nothing more.

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I'll be watching this eagerly - always nice to have a new LED to inspire another round of upgrades.

I always wonder about this theoretical limit of LEDs efficacy. We haven't reached it yet, so it's not a practical concern. But, I remember years ago when everyone said, in regards to Moore's Law, that there was no way chips would shrink beyond the theoretical 35nm limit. Now we already have 10nm silicon chips with Intel already working on 7nm and some stating that successful tests with a 2nm structure have been performed.

A theoretical limit is just that - a theory - until someone comes along and figures out to solve the theory and break the limit.

It is nice to see, that my comment sparked such a furious replies, but I want to ask a simple thing, as we're talking about LED vs Incadescents. Let's take frontier models, which are readily available for consumer markets. From the incandescents, it should be quartz halogen light bulb (bare bulb), either 12, 120 or 220V, say, G8 size, 100W. From LED's - choose what you see competitive. I'd like to see the LED, which directly replaces that halogen bulb in most important (size,power of output light) parameters.

ShineOnYouCrazyDiamond said:

I'll be watching this eagerly - always nice to have a new LED to inspire another round of upgrades.

I always wonder about this theoretical limit of LEDs efficacy. We haven't reached it yet, so it's not a practical concern. But, I remember years ago when everyone said, in regards to Moore's Law, that there was no way chips would shrink beyond the theoretical 35nm limit. Now we already have 10nm silicon chips with Intel already working on 7nm and some stating that successful tests with a 2nm structure have been performed.


A theoretical limit is just that - a theory - until someone comes along and figures out to solve the theory and break the limit.

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LED efficiency is not a "theoretical" limit per-se. It's a hard limit. Power Out cannot exceed power in. That is what limits lumens/watt.

ssanasisredna said:

LED efficiency is not a "theoretical" limit per-se. It's a hard limit. Power Out cannot exceed power in. That is what limits lumens/watt.

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That may be true, but power out is a sum of light plus heat. These efficiencies are at specific rated currents. Other technologies will allow better heat transfer and allow brighter light at higher currents. The linked Haitz's Law claims Cree had a 303lm/W prototype a few years back, and that breaks the 300lm/W theoretical limit. There are technologies out that that haven't even been discovered yet which will always break the laws of physics as we currently know them.

Now - back to the OP..... can't wait to see the numbers on the HI version when they are released. The HD LEDs are definitely an improvement over the XM-L2 in terms of tint and output color quality, but IMO it the HI LEDs which produce the best flashlight beams. Removing a primary and secondary optic combination and only having the reflector as the primary beam focusing optic produces amazing beams even when you aren't going just for throw. Every flashlight I've upgraded from a XP-G2, XM-L2 or even XP-L HD has produced a more satisfying beam with a XP-L HI in it's place.

CuriousOne said:

It is nice to see, that my comment sparked such a furious replies, but I want to ask a simple thing, as we're talking about LED vs Incadescents. Let's take frontier models, which are readily available for consumer markets. From the incandescents, it should be quartz halogen light bulb (bare bulb), either 12, 120 or 220V, say, G8 size, 100W. From LED's - choose what you see competitive. I'd like to see the LED, which directly replaces that halogen bulb in most important (size,power of output light) parameters.

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So are you giving me 100W to play with?

1) The topic was XPL2
2) Bulbs are just one part of the market. Far more power goes into commercial/retail lighting where LED beats florescent rather easily now and is cost competitive when similar features are provided.
3) If I was trying to replace a bulb, I would not use a single LED. It would be grossly the wrong approach optically for a round distribution. I would use 3030 or 2835 LEDs, 90CRI, probably about 20-25: 3030s, 2x 2835s. That would cost me about $1.00 - $1.25. Efficiency 80-100 LPW depending on what trade-offs I went with. Add in a driver and likely a 4-flow like thermal design. As you have expertise in electronics, I am sure you can tell me what the cost of the driver, PCB will be. If you want it to "warm-dim" add another $0.30-0.40.

ShineOnYouCrazyDiamond said:

The linked Haitz's Law claims Cree had a 303lm/W prototype a few years back, and that breaks the 300lm/W theoretical limit. There are technologies out that that haven't even been discovered yet which will always break the laws of physics as we currently know them.

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There was NEVER a 300lm/watt theoretical limit. The limit has always been the same, about 680 lpw for a perfect green LED, and 250 to about 425 lpw depending on the CCT and CRI.

No, breaking the LAWS of physics is not something that happens, though I cannot argue they have been "improved", i.e. Newtonian Mechanics. However, you are not asking for a "new law of physics", you are asking for 1+1 = 2.5 ... that is not a flashlight, that is a power generator.

https://en.wikipedia.org/wiki/Luminous_efficacy

Photopic luminous efficacy of radiation has a maximum possible value of 683 lm/W, for the case of monochromatic light at a wavelength of 555 nm (green).



I love it when I set off noobs who apparently want to just argue adamantly about things. Hang around a while - you'll make great friends here.

Laws are made to be broken - just give it time. Now, I'm going to go watch Interstellar again and see how to use gravity to fold the space-time continuum. Don't worry, I won't be responding to bait your argument.

ShineOnYouCrazyDiamond said:

https://en.wikipedia.org/wiki/Luminous_efficacy

Photopic luminous efficacy of radiation has a maximum possible value of 683 lm/W, for the case of monochromatic light at a wavelength of 555 nm (green).

Maximum for CRI=95 at 5800K (5800 K black-body truncated asymmetrically)	310[9]​[10]​	45%
Maximum for CRI=95 at 2800 K (2800 K black-body truncated asymmetrically)	370[9]​[10]​	54%

Theoretical limit for a white LED with phosphorescence color mixing

260–300[30]​

I love it when I set off noobs who apparently want to just argue adamantly about things. Hang around a while - you'll make great friends here.

Laws are made to be broken - just give it time. Now, I'm going to go watch Interstellar again and see how to use gravity to fold the space-time continuum. Don't worry, I won't be responding to bait your argument.

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I believe this is supposed to be a friendly place, but if you want to show your ignorance of technology, I am not going to stop you.

260-300 is the theoretical limit for a very specific case, which obviously you do not understand. This was an off-the-cuff number for laypeople, i.e. people like you, not for people who have some expertise in the field which you do not appear to.

This has been well understood since pretty much the 50's as pumped LED white is technologically just like florescent technology w.r.t. spectral efficiency, stokes losses, etc. In the LED field, the renowned Professor Ohno at Nist laid this out clearly in a research paper in 2005: http://ws680.nist.gov/publication/get_pdf.cfm?pub_id=841839

Here, let me give you an excerpt so you can gain some knowledge from this exchange. That number on the bottom, 294, is what most people like you quote without really understanding what it means. It is specific to a phosphor type, a CCT and a color temperature.

All the work on quantum dot phosphors is to narrow the bandwidth and tune the emission for maximum output.

LAWS are not meant to be broken. That is why they are laws. There are proposals for folding the space time continuum that do not violate the laws of physics. That is why the interest. Of course, gravity may not even be a fundamental force ... better do some reading

This is getting completely off-topic, so if you would like to learn more, feel free to PM me.

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Back to o.p. Hank at intl-outdoor has had sub 5000k v6 xpl for like a year, at least. I bought one in spring, thermal glued two CPU finned heat sinks together, open air aluminum heat sinking reflector, heat sink bezel with internal air flow, on heat sink pipe, on headband. Relative diffuser lux and eye agree, and cree pct, all agree 373 lumens at 700 ma. The xpl1 color is as nice as my xml2 t6 with 100 lumens less at 700 ma. Though in use, the candela is very important for perceived brightness. Really need a 26 mm mcpcb for a 42mm reflector. MTN electronics has 26 mm occasionally, but only Hank had the xpl. The real advantage is at 200 lpw heatsink requirements go down. So with my adequate heat sink, efficiency is more apparent. Also, so far, Love my xpl tints.

My buck driver is a switching. It will be interesting to see if I can get an extra 40 minutes on high. Already, I make my light unable to suck quicker than a full workday. But I have a pot for infinite variable control. So, with barely noticeable tiny dimming, I can get near 12 hours. My biggest issue this year wasn't dead cells, dim work lights. Rather, missing headlamps. 3 disappeared this year from the jobs. Pretty sure another trade stole the last one.

I am concerned that while the forward voltage is lower, the v6 is slightly lower stated lumens at 1000ma. Psychologically and heatwise, 200lpw at 2watts is important. In real world, the possible improvements are tint availability beyond Hank, runtime bump, heat bump. Tint availability(hopefully) and runtime bump, if true, will be the only noticeable change. Though I don't see the link between tint and the SiC3, only that other dealers have had enough time to catch up with Hank.

DIWdiver said:

Why would they update the XM-L2 when there's the XP-L (and now the XP-L2)?

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is there a chart for this or do i just need to know these 3 models and the rest is not so important anyway?
1. xpL2
2. xpL
3. xmL2