# How long do you think the XM-L2 will remain the king of bright EDC lights?



## michaelmcgo (Nov 3, 2014)

When I got into LED lights in the early 2000's there were new LEDs coming out every few months. Lately improvements have been incremental and the XM-L(2) has been the brightest EDC sized LED for the longest time.

Is there anything better on the horizon? I don't see the current generation of LED lights becoming obsolete for many years. How about you?


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## michaelmcgo (Nov 3, 2014)

I toil over this every time I buy a new light. I just purchases a Zebralight H52w but not without a few days of researching if something new was on the horizon. I have an original H501 and it drives me nuts that the emitter is a generation old...


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## cland72 (Nov 3, 2014)

I think the XPL offers the footprint of XPG, but the brightness of XML. If true, the XPL2 (I'm sure it'll come out at some point) will be the ultimate blend of brightness, throw, and flood.

The good news is your XML2 based lights will never output fewer lumens than they do today, so unless you get your kicks by upgrading to the latest and greatest, you won't need to worry. I still carry approx 200 lumens max on any given day.


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## Daekar (Nov 3, 2014)

Are you asking how long it will be until the maximum output emitter is sold in a different die/package? Or how long until efficiency with reasonable spectrum quality is increased meaningfully? There are a lot of dimensions to this, really. If they figure out a way to achieve higher surface brightness with the same efficiency, we could see the same output achieved in flashlights with smaller reflectors required for any given degree of beam control. I'd guess that LED packages will change slower even if phosphor changes don't because of the secondary industry of products like optics that have cropped up as the solid state market has ballooned into a juggernaut. The lumenaire manufacturers that compose the vast majority of the emitter market don't want to retool and redesign constantly because a new emitter package replaces an older one. With production levels so high, the cost of changing a production line and the other associated processes naturally gets higher, and even though large volume allows amortization across more parts sold, the progress of micro-level manufacturing as in emitters means that each generation will be, on average, more expensive to produce. To be honest, I'm totally impressed they've done so well thus far.

As far as current-gen XM-L2 lights becoming obsolete, I'd say that's a "somewhere between 5 years and never" proposition depending on what you're using the current light to do. Sometimes it's hard for me to remember, but I have some lights from the dawn of the Cree age (XR-E P3 and P4 emitters, I think) that are still totally adequate for 90% of what I'd want them for, and I walk each night with an incandescent Surefire lego despite the fact that I have a TK41 with a 4000K neutral emitter sitting at my bedside.


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## MichaelW (Nov 3, 2014)

Maybe if Cree comes out with a 3mm^2 die.
The efficiency of the xm-l, with the throw of xp-g.


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## GordoJones88 (Nov 3, 2014)

XM-L3 is just around the corner, any day now . . . wait for it . . .


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## StarHalo (Nov 3, 2014)

Why is the XM-L2 king, versus the MT-G2?


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## Ryp (Nov 3, 2014)

StarHalo said:


> Why is the XM-L2 king, versus the MT-G2?



I think 'cause there are no MT-G2 EDC lights.


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## Fireclaw18 (Nov 4, 2014)

Ryp said:


> I think 'cause there are no MT-G2 EDC lights.



Biggest problem is that MT-G2 requires 6 volts. This means that unless you have some kind of boost driver you'll need 2 cells in series just to get it to light.

Most EDC lights use one cell. One cell is smaller and better sized for EDC. It's also much safer.... no need to worry about 1 cell running down faster and reverse charging the other cell causing it to detonate.


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## zs&tas (Nov 4, 2014)

what we are saying is we want a 2ximr18350 MTG2 mule, should be quite small and bright


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## Danielsan (Nov 4, 2014)

Fireclaw18 said:


> Biggest problem is that MT-G2 requires 6 volts. This means that unless you have some kind of boost driver you'll need 2 cells in series just to get it to light.
> 
> Most EDC lights use one cell. One cell is smaller and better sized for EDC. It's also much safer.... no need to worry about 1 cell running down faster and reverse charging the other cell causing it to detonate.


yes and a new 6V emitter was just presented some weeks ago, forgot the name of it. I guess we will see some new multi cell lights with this emitter instead of the MT-G2


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## kuna (Nov 4, 2014)

GordoJones88 said:


> XM-L3 is just around the corner, any day now . . . wait for it . . .



Are you sure about that? I though the next upgrade from Cree was the XHP-50, which probably won't be any better for throw than the XM-L2.


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## DIWdiver (Nov 4, 2014)

Daekar said:


> Are you asking how long it will be until the maximum output emitter is sold in a different die/package? Or how long until efficiency with reasonable spectrum quality is increased meaningfully? There are a lot of dimensions to this, really. If they figure out a way to achieve higher surface brightness with the same efficiency, we could see the same output achieved in flashlights with smaller reflectors required for any given degree of beam control. I'd guess that LED packages will change slower even if phosphor changes don't because of the secondary industry of products like optics that have cropped up as the solid state market has ballooned into a juggernaut. The lumenaire manufacturers that compose the vast majority of the emitter market don't want to retool and redesign constantly because a new emitter package replaces an older one. With production levels so high, the cost of changing a production line and the other associated processes naturally gets higher, and even though large volume allows amortization across more parts sold, the progress of micro-level manufacturing as in emitters means that each generation will be, on average, more expensive to produce. To be honest, I'm totally impressed they've done so well thus far.



Certainly there's some truth to this. However, cost of LEDs is strongly linked to die size, so there's quite an economic incentive to reduce die size while maintaining lumen output. New products will continue to be built, and will take advantage of new LEDs, pushing older, more expensive products through their life cycles.

I think the pace of progress is slowing, at least on the LED front. We're at the point now where around half the power we put into an LED comes out as visible light. So doubling the current state-of-the-art efficacies is all that is EVER going to be possible with ANY technology. And I can't believe we'll get there as fast as we got the last doubling, or the previous one. You will continue to see incremental improvement in efficacy, brightness, CRI, and price, but where you are going to see more radical innovation is in luminaire development.


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## Julian Holtz (Nov 5, 2014)

A new trend for some time now is to build multi-die LEDs vith higher voltages, as these are better suited when the whole assembly is supplied by a driver running on 110/230VAC, and are cheaper compared to a number of individual LEDs with one die each.

But multi-die LEDs are not very well suited for flashlights operating on <4V.
It is a nice aspect of nature that the voltages of LiIon cells and LED dies match so nicely, so that only a minimum of technology is needed to make them compatible. A number of constant current drivers is enough.

So, if we see more efficient multi-die LEDs, this efficiency gain is offset by the conversion losses if a step-up driver is needed to power them. As the focus of R&D now lies on multi-die LEDs, I expect quite some time to pass until we see an improvement in single-die ones.


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## Anybodysguess (Nov 5, 2014)

Who says LEDs will always be the best? Before LEDs were invented fluorescent was the most efficient light source. Maybe the "next big thing" won't be LED at all.


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## radiopej (Nov 5, 2014)

Next year is the international year of light technologies.

I think the XP-L is gaining traction - Fenix seems to have started switching.


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## DIWdiver (Nov 5, 2014)

Development in multi-die parts and single-die parts isn't mutually exclusive. As technology improves, both applications will benefit.


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## mattheww50 (Nov 6, 2014)

Improvements in LED performance are evolutionary rather than revolutionary at this point. As time goes on, various minor improvement raise the output incrementally. Note that XM-L2's are now available as U3's. I would not be surprised to see a U4 early next year,that is, if they don't decide to call it an XM-L3. The XM-L2 will remain king of the hill for as long as the Marketing Department thinks it make sense. The longer it takes, the higher the yield of top bin devices. The decison to introduce a new name is not a technical decision, it is a marketing decision.


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## Epsilon (Nov 7, 2014)

XM-L's are different from XM-L2's, so calling it a different name is obvious in both technical and marketing sense. But calling an XM-L2 U4 an XM-L3 is not correct, it is just an efficiency step due to quality improvements of some sort in the production process. When switching to a different lay-out, dome, phosphorus or something like that, it will likely be called XM-L3.

XP-L's have the same die as XM-L's in an XP-G size footprint, so therefor does not add a lot of throw. If it even has added throw, it will be due to the different dome.

As far as XM-L(2)'s as king of the EDC lights: In my opinion it already isn't, because I do not EDC a large light. If you qualify EDC as P60 + 18650, than maybe it is still king. But for me, 1x CR123, 1x18350, 1xAA, 2xAAA with at most an 18mm reflector are more like EDC for me. In that realm the XP-G is king in my book, just by limitations of thermal design and the smaller die in the small reflectors. You can not run XM-L's even at 3A for long times in lights that size and the light does not throw very well due to the small reflectors.

Things I would like to see from Cree (or any manufacturer) are the obvious things:
- Higher Efficacy on the same die sizes
- Lower Vf on existing die sizes, 5A is not sustainable on an 18650 at Vf + 0.2v for long periods.
- From Cree specifically: A larger die with the same technology as the XM-L2, for running 4.5A-6A within spec.


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## BeastFlashlight (Jan 22, 2015)

cland72 said:


> I think the XPL offers the footprint of XPG, but the brightness of XML. If true, the XPL2 (I'm sure it'll come out at some point) will be the ultimate blend of brightness, throw, and flood.


NOOOO don't say that!! Is XPL2 close at hand? I just bought a sweet Quad XPL single 18650 flood monster, i'd hate to have XPL2 come out right afterwards (It's in the mail i didn't even get it yet).

Is XPG2 the longest running LED without an upgrade? It's been out forever now, XML2 had 2 upgrades - U2 & now U3. But XPG2 remains the same


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## cland72 (Jan 22, 2015)

BeastFlashlight said:


> NOOOO don't say that!! Is XPL2 close at hand? I just bought a sweet Quad XPL single 18650 flood monster, i'd hate to have XPL2 come out right afterwards (It's in the mail i didn't even get it yet).
> 
> Is XPG2 the longest running LED without an upgrade? It's been out forever now, XML2 had 2 upgrades - U2 & now U3. But XPG2 remains the same



This is entirely speculation, but I would imagine the XPL2 won't come out for another 2-3 years, based on what we've seen previously from the XPG and XML upgrades.


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