# Got an XT-E drop-in today; first impressions of it and the LED.



## RedForest UK (May 9, 2012)

It was from KD, the 3 mode $7.99 one. It came with a NANJG 1A max driver (good quality 7135 based programmable and fully regulated, as used by nailbender etc). This means that for anyone who accidentally ordered the 5 mode it should be quite easy to change to 3 or 2 mode etc with a quick solder job. The 3 mode one I have though seems to have been set by soldering the legs of one of the components on the inside rather than connecting to the right star on the back, so harder to switch to a different mode set.


Now for the interesting bit, the new LED type: The XT-E itself is interesting, but in all honesty disappointing. Brightness is fine, it seems similar to my XP-Gs. But there is a lot of colour spread across the beam, way more than any XM-Ls I've seen, it gives the hotspot and spill a clearly yellowish corona with more blue central areas. The beam angle from the LED itself also appears to be very wide, it will not focus properly in an XP-G reflector. It actually seems to work best with an old MC-E (very wide beam angle) reflector I had lying around.


On the whole, the drop-in seems well constructed and very good value, and the new LED is a nice novelty. But I think the main selling point of these for CREE will be their low price/efficiency ratio (so big sales to light bulb/lighting array companies), rather than their accurate colour distribution or other characteristics desired for use in torches.


Of course I only have one sample LED, in a cheap drop-in, so these observations may not apply to all CREE XT-E based lights out there..



(WRT the sub-forum this thread is in I thought that 'LED flashlights' was best suited as it is a comment mainly on a specific LED in use in a flashlight and soon to be in use in many other ones. Of course it could be argued this thread better belongs in the 'LED' section, the 'Flashlight Electronics' section, the sticky P60 drop-in thread or the 'Budget' sub-forum. I just made a call on where I thought it should be. To anyone who can, feels it is in the wrong place, and is bothered enough about it, feel free to move it to somewhere else where you feel it would be better placed.)


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## Animalmother (May 9, 2012)

Did you manage to take any pics of this rainbow beam? Others also mention the color spread issue. Were you able to tell how were the beam characteristics if the light were an even tint? Was it a bright XPE/XRE or an XPG with more throw? I'd love to hear anything you have to report on the XTE because from my understanding the only issue is the rainbow beam. I am interested to see what it looks like. 

I once had a Energizer Lithium 2AA w/XRE(they later came with an XPE). The reflector was incredible small. For it's size... it could throw real well. I wanna say around 5k maybe 6k lux. It impressed me so much that I hoped the XTE would be around the same type of beam profile with a small body and short reflector and a burning hotspot.


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## RedForest UK (May 9, 2012)

No, sorry, I can't do pictures at the moment, I'm way too bogged down in revision. Unfortunately the XT-E is no-where near XR-E, it is less focused than an XP-E and even an XP-G by my reckoning and more like an XM-L with a smaller footprint. I don't know why so many expected it to give more throw than an XP-E/G to be honest as the phospher application used doesn't lend itself to more throwy beam but is simply a cheaper manufacturing technique.

EZ900 XR-E will be king of the hill for throw for a while I think, due to the smaller beam angle from their lense. I just wish CREE had kept producing them with increasing efficiency bins as the technology advanced. I would imagine we could be on R4/5 by now which would have been awesome from an XR-E.


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## jorn (May 9, 2012)

Lets hope they push it some more and make some new reflectors for it . The xp-g started as a "max 1 amp led" and was not too impressive in the first lights.
I dont know what is worst. Rainbow tint (xt-e) or super ringy beam (xr-e). I guess we still have to wait before someone makes a reflector to max out the throw. With 1 amp draw,it will have good runtimes atleast. Lets hope someone cranks it up to 1,4-1,5A and see if it starts to shine.


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## RedForest UK (May 9, 2012)

Yeah, personally I've got some Nichia 219 92 CRI 4500k on the way and 1.4A single mode drivers. So I'm planning on swapping the three mode 1A driver for a 219 and using this XT-E with a single mode 1.4A driver in a more 'tactical' style light for which the tint and beam shouldn't be such an issue. 

I really think the strength of XT-E will be in cheap purchase costs and good performance at higher temperatures, not in colour fidelity/distribution, beam smoothness or surface intensity (all of which are better in at least 1 other emitter type imo). These strengths will lend themselves well to manufacturers of light bulbs or lighting arrays where low unit costs and good life/efficiency at high temperatures long-term are key considerations. I think these applications/buyers are what/who the XT-E was mainly designed for/marketed too by CREE, and eventually where they will find their niche. 

We may well also see a lot more of them in very cheap generic ebay and/or mass produced chain store lights wanting to keep production costs as low as possible and for whom the LED is the most expensive component, which will be a big step forward in efficiency over other options at those prices on the market at the moment.


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## A10K (May 9, 2012)

I have the same drop-in on order, and a few 20mm stars coming in from Cutter. Several people have posted beamshots of different XT-E builds over at MTBR, and the conclusions are about the same when it comes to color--its not the cleanest. Removing the dome makes it even worse, though it does improve throw a good bit. The one thing to consider is that the XT-Es currently being passed around are still part of CREE's first batch--apparently people with early XM-L emitters had issues with green or yellow tints, while newer XM-Ls are typically more pure in color.


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## BLUE LED (May 9, 2012)

Eagletac has experienced this problem with the XT-E. The blotchy beam profile combined with yellow and blue seems to be a big problem. I was looking forward to trying out the XT-E in the Eagletac D25C and D25LC2 Clicky. However most of the distributors have sent back these models.


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## ergotelis (May 9, 2012)

I made my first test with cree xt-e from cutter. Their beam profile is different from xp-g, but in some cases an xp-g reflector can work for a xt-e.
I modded my armytek predator with a xt-e(previously modded with xm-l) and its performance is 22,500 lux & 360 OTF against the classic xp-g which has ~17,000 lux and 340 OTF). So in this case, it worked. There is a strange yellow filling in the hotspot, but overall beamprofile is nice. Some reflectors do not work, others possibly yes. If you manage to focus the led on a reflector, you should be probably getting the same yellow filling in the hotspot. Mag reflectors seem to work fine. Generally it is a very difficult led to focus properly.

As for its lumen output, a xt-e R5 has the same output with a xp-g S2. All xt-e and all xp-g S2 are from cutter, all had almost the same performance @700ma. 
Test is continuing, if you have any specific demand ask me, i have tested already more than 20 reflectors.


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## Blitzwing (May 9, 2012)

Thanks for the review - I won't bother with the XT-E then. 

I too wish Cree would come up with a new thrower friendly emitter, or at least more efficient XR-E.


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## Animalmother (May 9, 2012)

Blitzwing said:


> Thanks for the review - I won't bother with the XT-E then.
> 
> I too wish Cree would come up with a new thrower friendly emitter, or at least more efficient XR-E.



Thats what i was hoping for too. Like a XR-E in the R5 bin.

Or U2! ))))))))))


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## A10K (May 10, 2012)

Blitzwing said:


> Thanks for the review - I won't bother with the XT-E then.
> 
> I too wish Cree would come up with a new thrower friendly emitter, or at least more efficient XR-E.



There's a quote in the MTBR XM-L release thread where somebody concludes that the XM-L probably isn't appropriate for bike lighting. Truer words never spoken.:thumbsup:
I think there's going to be a "growing pains" period where the XT-E undergoes some refinement on CREE's end, and where the proper reflectors/optics are developed for it.


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## saabluster (May 10, 2012)

A10K said:


> There's a quote in the MTBR XM-L release thread where somebody concludes that the XM-L probably isn't appropriate for bike lighting. Truer words never spoken.:thumbsup:
> I think there's going to be a "growing pains" period where the XT-E undergoes some refinement on CREE's end, and where the proper reflectors/optics are developed for it.



There is absolutely no reason the XM-L wouldn't be good for bike lighting. It is simply about how the designer manages the light. Please don't spread myths.


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## A10K (May 10, 2012)

That's exactly my point. The fact that they are proliferating in all manner of bike lights, especially high end ones, shows this. I was pointing out that some people expressed skepticism on the applicability of the larger-die, higher-current XM-Ls when they were first released too.
As the XT-E/XB-D emitters are in the appropriate voltage/current range as other commonly used flashlight emitters, I think there's going to be a lot of development yet, starting with Eagletac sorting out their color issues.


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## fyrstormer (May 10, 2012)

Cree's single-minded goal of improving output at the sacrifice of all other concerns will come back to bite them eventually. Nichia is gaining a lot of ground with their cool-tint Hi-CRI emitters.


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## csshih (May 10, 2012)

The XT-E emitters are meant to be a lower cost replacement of the XP-E.

The emitters will work fine in flashlights, however, enthusiasts won't like them because of the die structure. this isn't a matter
I'm not sure where the thinking that XM-Ls wouldn't work for bike lights, the emitter is just a little bit larger.

The XT-E, on the other hand, has a flip chip design. if you're looking for throw it physically won't work.



fyrstormer said:


> Cree's single-minded goal of improving output at the sacrifice of all other concerns will come back to bite them eventually. Nichia is gaining a lot of ground with their cool-tint Hi-CRI emitters.


only in very niche markets. to everyone else, brighter is better. just look at the cfl market - no one focused on CRI.

Craig


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## Mike S (May 10, 2012)

Where exactly does the blue tint of the XT-E come from when it's positioned into a reflector? It's clear that the XM-L's green/yellow tint is due to its color separation at the extreme edges of the viewing angle. In comparison, the XT-E's color separation is minimal. However, with the use of a reflector, the beam profile of a 5000K XT-E can produce both blue and yellow. Without looking at the spill and only focusing on the hot spot, it's hard to tell what color temp the LED is supposed to be.

It appears to be a characteristic of LED's with a "flooded" phosphor area. Those 1/4 and 1/2 watt packages like the ML-E/ML-B and even the CLA2 are effected the same way. On their own the color is nice a even, but once they're positioned inside a reflector a very strong blue tint can be seen.


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## yifu (May 10, 2012)

In the general market, which constitutes the majority of demand, no one cares about CRI. I've never seen a light/bulb in stores where CRI is listed as a spec, and sometimes not even the colour temperature, just "cool white" or "daylight white". And in applications where CRI is important, such as in surgery, costume retail, the dominating light source are either ceramic metal halides or just halogen.

The main selling point of the silicon carbide dies is the low cost of production and the very low thermal resistance as well as less sag with increased temperature. All of which are important selling points for mass market adoption, where heatsinking solutions are often lacking.


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## fyrstormer (May 10, 2012)

csshih said:


> only in very niche markets. to everyone else, brighter is better. just look at the cfl market - no one focused on CRI.


Not "nobody", exactly. Ever heard of Ott Lites?


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## saabluster (May 10, 2012)

Mike S said:


> It's clear that the XM-L's green/yellow tint is due to its color separation at the extreme edges of the viewing angle.



Another myth. It is not color separation. It is the fact that at that angle the light is going through a larger cross-section of phosphor.


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## brted (May 10, 2012)

yifu said:


> In the general market, which constitutes the majority of demand, no one cares about CRI. I've never seen a light/bulb in stores where CRI is listed as a spec, and sometimes not even the colour temperature, just "cool white" or "daylight white". And in applications where CRI is important, such as in surgery, costume retail, the dominating light source are either ceramic metal halides or just halogen.



A lot of people don't like CFL bulbs, but they may not know that it has to do with CRI. I think eventually CRI will be required on the packaging along with CCT, lumens, lifetime, and power consumption which are already required in the US. Also bulbs that don't have CRI of 80 or higher do not qualify for Energy Star certification.


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## orbital (May 10, 2012)

+

RedForest, you should not have said where you got it,, and instead said you spent $120 for it.


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## Mike S (May 10, 2012)

saabluster said:


> Another myth. It is not color separation. It is the fact that at that angle the light is going through a larger cross-section of phosphor.



Right, I understand why it happens, but "color separation" is the term that I see used quite a bit on the various lighting forums when referring to that tint shift.

What's the more correct term for it?


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## qwertyydude (May 10, 2012)

I don't think anyone who says the XM-L isn't suited for bicycle lighting actually ride a bicycle at night. It's ideally suited for bicycling.

Read all over the mtbr forums and people complain day in and day out that regular led lights are too throwy with traditional flashlight reflectors. Most of the budget bike lights are simply converted flashlight heads with a separate power brick. But having a narrow bright beam makes riding at night on bike trails dangerous, you can't see what's off to the side and you end up with basically tunnel vision.

What you should ideally emulate is motorcycle headlights. These have a beam that goes out but also speads out a decent amount, not a pencil beam, they also have a generous spill, it's much like a car headlight. And the XM-L in a small reflector like a P60 does pretty much this, albeit with more glare toward on-coming traffic. But riding a mountain bike that's not that important. And there's absolutely no need for 1000 lumens like that on a road bike riding in the city so the glare problem is moot.


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## Blitzwing (May 13, 2012)

Gotta agree qwerty. An XML on the bar and one of the helmet is good.


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## A10K (May 17, 2012)

People really misread my post, that's all I'll say. I use an XM-L for some of my night riding.

My XT-E drop-in has also arrived, its a 3-mode like the OP's, driven at about 1A based on tailcap measurements (using CREE's product comparison tool this comes out to about 370 emitter lumens, guessing around 300 OTF). Part of the hotspot and outer spill is cool white, but the corona and center of the hotspot have significant yellow artifacts in them. I can actually get the center of the hotspot to form an "X" depending on the focus, meaning that the LED projects an image of the "X" from the die. Its noticeable on white walls, smooth concrete, and clean asphalt. Against grass, vegetation, or urban visual noise, its not a significant issue and the beam appears cool white. I threw it on my bike for a little bit of street riding and I think the throw/spread is decent for that application, though I don't have any XP-G drop-ins to directly compare to (Hi-CRI isn't in the same ballpark output-wise).


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## sportyaccordy (Jan 5, 2013)

qwertyydude said:


> I don't think anyone who says the XM-L isn't suited for bicycle lighting actually ride a bicycle at night. It's ideally suited for bicycling.
> 
> Read all over the mtbr forums and people complain day in and day out that regular led lights are too throwy with traditional flashlight reflectors. Most of the budget bike lights are simply converted flashlight heads with a separate power brick. But having a narrow bright beam makes riding at night on bike trails dangerous, you can't see what's off to the side and you end up with basically tunnel vision.
> 
> What you should ideally emulate is motorcycle headlights. These have a beam that goes out but also speads out a decent amount, not a pencil beam, they also have a generous spill, it's much like a car headlight. And the XM-L in a small reflector like a P60 does pretty much this, albeit with more glare toward on-coming traffic. But riding a mountain bike that's not that important. And there's absolutely no need for 1000 lumens like that on a road bike riding in the city so the glare problem is moot.



Motorcycle headlights are designed to the same standards as car headlights... they often share components (Hella projectors for example)

Problem I am finding with LEDs, at least in traditional configurations, is that they are terrible with spill because of their angular falloff. A motorcycle/car headlight takes light from a point source and redistributes it through a shield and parabolic reflector, giving it spread + throw... a typical LED or even an LED array is just a spotlight

For bike riding where speeds are low I think a regular LED is probably good enough. Even the glare is OK, as you want to be seen. But if you really want that wide beam like a new DOT headlight you will definitely need some sophisticated optics. Even an LED in the place of an old filament would not work well.


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