what's the difference between XML vs XML2 ?

picard

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what's the difference between XML vs XML2 ?

Is there big difference?

does XML2 have tighter spot ?
 

DellSuperman

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XM-L2 is the 2nd generation XM-L.
It has better efficiency so it should produce more lumens.
The difference stated by the manufacturer is roughly 20% improvement.

As for hotspot brightness, it should depend on the reflector or optic rather than the emitters you mentioned.

- JonK
 

BeastFlashlight

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When do u guys think XML3 will come out? XML4? How fast do u see these LEDs evolving, maybe 1 level of improvement per year? I'm shocked that NEW lights are still coming out with XML U2 that's 2 bins back from the current best.

I hope that the voltage requirements and drivers of XMLs stay compatible down thru the years because I'd really like to be able to simply swap out my LEDs on my custom lights as they improve. I have really nice custom hosts (all with XML2)
 

maoku

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XML2 20% higher than XML on the brightness, and the encapsulaiton is different
 

TEEJ

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When do u guys think XML3 will come out? XML4? How fast do u see these LEDs evolving, maybe 1 level of improvement per year? I'm shocked that NEW lights are still coming out with XML U2 that's 2 bins back from the current best.

I hope that the voltage requirements and drivers of XMLs stay compatible down thru the years because I'd really like to be able to simply swap out my LEDs on my custom lights as they improve. I have really nice custom hosts (all with XML2)

There's no set amount of improvement. Sometimes, they make the die smaller, and throw is improved, sometimes they squeak some more lumens out of them, etc.

The way I see it, just get the light that does what you need it to NOW. If its working for you, you're done. If you want a light that's smaller but the same performance, or, find it WASN'T working for you...then get a better light when available, and so forth.

:D
 

ROB21

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So, does it generate the same amount of heat at the same lumen value?
 

yifu

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Ok here are the improvements...
-Die shrink of around 10%
-Die change to new SiC generation (new process beginning with the XB-D)
-Binning at 85 degrees celsius(used to be 25 degrees)
-Removal of current spreaders and reduction in bond wires by 1(so we can drive it to 6A without the wires melting:devil:
-Efficiency increase of around 10% (at 85C)
-Substantial cost reductions (half the lumen per dollar cost)
-Longer L70 lifetime
-And dome is easier to remove (personal experience)...

I think it's a good upgrade.
 
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BeastFlashlight

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The way I see it, just get the light that does what you need it to NOW. If its working for you, you're done.
:D
I'm pretty satisfied with my mods, but the #1 reason i will continue to upgrade the LEDs if I can will be for the improved light to heat ratio, the ideal goal being the point where they can run continuously without over heating. Like the SolarStorm that we have how great would it be for that to handle the heat continuously?
 

PocketBeam

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Let's keep things on topic.

Yifu, great information. That is the first time I have seen such concise information. Was there a single source for the information? When I read the Cree documentation it didn't mention all those details.
 

bose301s

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Ok here are the improvements...
-Die shrink of around 10%
-Die change to SiC (new process beginning with the XB-D)
-Binning at 85 degrees celsius(used to be 25 degrees)
-Removal of bond wires (so we can drive it to 6A without the wires melting:devil:
-Efficiency increase of 10% (at 85C)
-Substantial cost reductions (half the lumen per dollar cost)
-Longer L70 lifetime
-And dome is easier to remove...

I think it's a good upgrade.
A few points that are just blatantly wrong here. Cree has always used SiC wafers for their LEDs. XM-L2 is just the 3rd gen SiC product, but nothing fundamentally different on that front. Also, the bond wires are still there, in fact instead of 3 of them there are now only 2 which is the probable reason for the Vf of the XM-L2 being higher. What was removed were the current spreaders on the top of the chip and went to a new FC style.
 

yifu

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Yes, i phrased it wrong, i meant a new SiC process which reduces cost, and yeah i meant current spreaders, which tended to melt when driven very hard, even though the phosphor could take more... Now the XML2 can put out nearly 1500 lumens at 6A with good heatsinking. I will rephrase everything
-Die shrink of around 10%
-Die change to new SiC process (new process beginning with the XB-D)
-Binning at 85 degrees celsius(used to be 25 degrees)
-Removal of current spreaders and reduction in bond wires from 3 to 2 (so we can drive it to 6A without the wires melting:devil: and the aspheric beam looks nicer
-Efficiency increase of 10% (at 85C)
-Substantial cost reductions (half the lumen per dollar cost)
-Longer L70 lifetime
-And dome is easier to remove (personal experience) for more throw...
 
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uk_caver

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Is the lumen-per-dollar point related to what it currently costs Cree to make one device compared to the other, or is it a bit of a spurious PR thing - a comparison over time between product costs or prices at launch, not between devices at the same point in time?

LEDs used to be more expensive, but all that seems relevant for a designer at the moment is what's currently available and what the current price/performance is, and maybe what is expected to happen in the near future.
 

RoGuE_StreaK

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I hope that the voltage requirements and drivers of XMLs stay compatible down thru the years because I'd really like to be able to simply swap out my LEDs on my custom lights as they improve.
As long as you are using constant current drivers then it shouldn't matter a damn, unless for some bizarre reason the Vf jumps massively. Most are decreasing substantially, which just means you'll run with the same current for longer before the driver gets out of regulation.

The spec sheets say 3000mA max current. Where did you find the 6A spec?
There is no spec; this is purely through people's experimentation, you'll find here that we see max limits as a challenge rather than a rule :D Note that you need seriosly good thermal dissipation to do this kind of thing. Also the spec sheets are written with a mind of reaching thousands of hours runtime; most here will never run a flashlight anywhere near that long, so can afford to push the LED further than specced.
 

yifu

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The spec sheets say 3000mA max current. Where did you find the 6A spec?
Good manufacturers of anything ALWAYs intentionally underrate their products, i.e. McClickys rated for 3A can take around 8A before melting, hard disks with MTBF of 1 million hours can almost always take more, a lift rated for 15 people can definitely take 50 or more before snapping:devil:. The 3A rating is just the conservative suggestion made by Cree for safe operation over tens of thousands of hours, the lumen increase after that is almost linear until 5A, which means that it can take a heck of a lot more.

We CPFers around here like to take things to the next level, for instance, the DEFT-X runs an XPG2 at double its 'max current' for nearly 800 lumens out the front and half the stuff on the B/S/T are overdriven for example. The XML2 will output nearly 1700 lumens at a 6A driven current on a direct to copper setup, and if that is then dedomed you will be looking at a 200% in lux over a 3A domed XML2 in the same light. Long term stability is an issue but after running a dedomed AND overdriven LED for hundreds of hours no loss showed up on a lux meter. After that time some new LED would have come up anyways so L70 lifetime is irrelevant for flashlight use.
 
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