Similar LED to CREE XP-E

The XP-G2 die is 2.2 tines as large, the maximum surface brightness is comparable to the XP-E2, so you get a bigger beam of the same brightness.

OK, thanks. Is that 2.2x the area? From the OP it sounded like keeping the beam size the same was important, and I assume he was using a domed XPE.

Flashlights running 2A (7W) get quite hot over time but they work fine.

Btw, reflowing 8-10 XP-E2’s plus dedoming is a different story, quite a project and I do not have that number of Noctigons.

I’ve told you that I currently use XP-E Q5 LED, but I’ve some doubts about it.
Picture of the LED:

I’ve a flashlight with a LED sold as a XP-E Q5 but the dome seems to be slightly smaller.

Do you recognize them?

Hello,

You don’t have any idea?

As XP-G2 LED has been suggested, I’ve checked for dimensions.
The die have a size of 1.4mm x 1.4mm against 1mm x 1mm for the XP-E.
However I think that a de-domed XP-G2 (or maybe XP-G3) could have a similar beam angle than a domed XP-E/XP-E2. What do you think about that?

If it can be similar (or narrower) I will try to find someone to make the dedoming process because I cannot do it myself.

Hi Yoann.

If those photos are from a cheapass SK68 clone, chances are that stuff doesn't even equips a genuine XP-E. Maybe some botchy mean-CRI CrappiceBlight…

In such a case, maybe this is what your're after, performance & economy wise:

Hope this helps my dear.

Cheers ^:)

Hello,

Thank you very much for that.
After some researches, XT-E seems to be quite similar to the XP-G2. Both have a dome radius of 1.53mm and both have an viewing angle of 115°. Thus I think that they have the same die size (I didn’t manage to find the die size of the XT-E). Tell me if I’m wrong.

If I’m right, the main difference is the output brightness.

In my previous post I spoke about XP-G3 but the die seems to be bigger than the die of XP-G2.

Regarding your links and other product on the website I do not understand some things.
For example on your second link:
https://www.fasttech.com/products/1609/10004538/4963402
There is a max lumens of 456.
But when I choose single piece (also XT-E R5-1A):
https://www.fasttech.com/products/1609/10004538/1347105
it is wrote 496Lm.
Why it is different. Moreover on Cree website it is wrote 629Lm
http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Discrete-Directional/XLamp-XTE-White

Yoann, unfortunately FastTech is not known to provide consistently accurate information about their products. When I need specific product information I log in on their website and make an inquiry about the product, their customer service usually works nicely.

Regarding your doubts about the product, check this out:

  • XT-E R5 bin is 139-148 lumens at 350mA, 85º. At 1'5A luminous flux is ≈3'08 times that, thence 441'98 average lumens.
  • XT-E R2 bin is 114-122 lumens at 350mA, 85º. At 1'5A luminous flux is ≈3'08 times that, thence 363'44 average lumens.

629 lumens? Flashy numbers, yeah. Maybe possible on a bin unheard of, a higher driving current, smoking some crack, and/or any combination of the aforementioned…

And please bear in mind that, in practice, you may find yourself somewhat hard-pressed to say an R5 is noticeably brighter than an R2; you'll notice a difference, yet it won't be as noticeable as you may think to the naked eye. I'd take the warm whites, and of course some could argue it is a matter of personal preference but, I am not the first to say the reason for the higher vision comfort with warm/neutral white light is in some way related to the low temperature of the available light sources at night which mankind has evolved with: campfires, torches, etc.

Cheers ^:)

It seems that XT-E is a good tradeoff between a narrow beam and a bright beam.
The tint is not really a criterium of choice because it is not for a night vision but for a night lighting effect. It is why I looking for the narrower and brighter beam possible. Do you know which tint is the more visible into smoke or fog?
CREE XT-E should give me a larger beam than with XP-E because the dome is a bit larger. But output brightness seems more important at high current. As with XP-E/XP-E2, can I easily overdrive XT-E to increase brightness? For example up to 2A, 2.5A or more? (Of course with a good heat sink).
I didn’t manage to find plots representing relation current/lumens for the XT-E.

Yoann, with regards to the tint all I can say is the colour temperature of classic fog lights is warm white (≈3200K).

The die size of the XT-E is the same as that of the XP-E, “E” class…

If you really want a narrow beam you may want to invest on some lenses, but that'll add to the cost.

Overdriving the led? I do not think you'll end up getting a worthwhile performance boost vs the cost of the required cooling improvements (reflowing the leds onto copper DTP PCBs, etc). I'd (first) consider using a clearly higher output led (XM-L2…).

XLamp XT-E datasheet -> Page 24/38 for the relative luminous flux vs current graph.

It is a new version of the doc, I had an older one. The graph shows now 327% relative luminous flux at 1500 vs 350mA.

Cheers ^:)

Hello I have XP-L leds that use the same die than XM-L2. However to obtain similar beam I need a very big lens at a more important focal length. Then I have a more important output but it is difficult to concentrate a large part of the beam (a lot of light is lost between the lens and the led). For now I have lens of about 22mm (diameter) and a focal length of about 12mm.
If I can find lens with 25-26mm diameter and a focal length 15-18mm I think it will be great for XT-E.

I will buy XT-E leds and I will test them with my lenses.

I see in datasheet that exists XT-E S2 and S3 but they are not sold on FastTech.com.
Do you know where I can find them?

R5 if you are interested.

Thank you, but on AliExpress it is really more expensive.
For buying XT-E R5 1A it is more interested to buy them on FastTech (arround 5 USD for 5 pieces).
In fact datasheet specify S2 and S3 bin for the XT-E. It is for why I’m looking for a shop to buy S3 (else S2) bin.
I’ve found XT-E S2 1A on ebay but with a huge price (not acceptable) and I cannot ffind S3 bin.

Hello,
Just to give some information that may be useful for someone.
I’ve bought CREE XT-E LEDs and compared them to CREE XP-E.
Even if they have the same die size, I obtain a larger beam than with XP-E. The primary optic of the XT-E is bigger than the primary optic of the XP-E.

Then I tried tu re-use my XP-E Q5 (from flashlight). However, I obtained a strange behavior.
First I tried to replace the original flashlight driver but a simple voltage/current regulator in order to have only one mode (on/off).
For that I use this kind of power supply: Power supply
I’ve set it to limit at 3.2v and 1.5A, but when I connect the LED I can only mesure 0.2A…
By discussing on an other forum I tried to increase the voltage, when I’m arround 5 I’ve only arround 0.7A. After the LED burnt…
Does I miss something regarding the usage of these LEDs?

Yoann, with the limited information you are providing, can't really be sure what you're doing wrong… maybe those current measurements aren't accurate. Are you providing enough voltage leverage at the input?

You don't really need to mess with the voltage trimpot, leave it at full throttle.

Start with the current trimpot at a minimum/low value. Connect the emitter in series with an amperimeter at the output, or set it in series with a low value resistor where you'll monitor the voltage drop at its leads, so you can determine the current flowing through the load: V = I × R, thence for an R200 (0.2Ω), at 0.7A of current flow you'll measure 0.14V at the resistor terminals.

Mmm, wait, there's an R050 sense resistor on the board. Measuring the voltage at its leads will give you the current output value: 0.05V/A (I = V / R). As long as your voltmeter is accurate enough, that is.

Cheers ^:)

P.S.: please, @#$% with those “local” aliexpress links, please post only global site links. Not only I do not want to open despisable & clownily translated item links, it also happens the friggin thing starts to think I “like” such a crap by default, and it forces me to use the “Go to Global Site” link to restore normal operating conditions. Thanks.

Hello,

First, I’m really sorry for the link. I always use the global market (english) but sometimes it changes automatically chen browsing some links on the Web.

This is more information about the usage and connections.
The power supply module is supplied by a laptop computer switching power supply 12V (around 3A).
The led is connected in series with the Amperemeter to the power supply module.
For configuration of the module, I disconnect the LED and I can measure voltage and current (short circuit current) and set them with potentiometers.
I do not let free (no limit) the voltage) because when I tried my XP-E Q5 (it is what is wrote on description when I bought it) with the configuration 6V and 1A it burnt in some miliseconds.
Before removing the led orignal LED driver I’ve test the current throwing into LED driver and the LED. I mesure about 1.7A for a voltage of about 4V. Thus I know that the led can support this power. I only remove the driver without any changes on the led heat sink.

I also tried to test an CREE XP-L LED with a similar configuration (3.5V 1.5A) and I obtain a similar result.
I get 0.12A with the potentiometer connected in series.

Seriously?

Damaged CC/CV module I'd say then, it may be outputting some nasty voltage peaks…

Other than that, no idea at this moment. :|

Cheers ^:)

Hello,

I’ve potentially found the problem…
it seems that the problem come from the cables used.
I’ve changed cables by bigger ones and for the same voltage I obtain a greater current.
Now I can reach 1A with about 4V it is still not that the datasheet describe but this made a huge improvement.

However, if the problem come from the cable impedance, I still not understand how it can lead to LED destruction.
If I’m not wrong, in this circuit, cables can be assimilated to low value resistors. So yes, they contribute to reduce current flowing into the LED for a given voltage. They also have a voltages on their ends thus the voltage of the LED is not the voltage of the power supply output. I don’t understand why they burnt.