# Cree R2 availability?



## Helmut.G (Aug 5, 2008)

I just visited the forum of a german LED shop where I hadn't been for months because CPF is so interesting. There I read that the company used their integrating sphere to measure R2 LEDs bought from other LED shops and found that they're putting out less lumens than their own Q5 ones, i.e. are _fake_.
They also claim that they have a statement directly from Cree's "leading technicians" that R2 LEDs are only available in samples at the moment.
This kind of shocked me as I trust this forum and it means that all the R2 things from DX and even some quality flashlights claiming R2 emitters are all scam 
can someone please tell me if thats really really true or if my post is just some kind of nonsense because I just can't believe it


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## jirik_cz (Aug 5, 2008)

Can you post a link? What "other led shops"? I wouldn't be surprised if KD/DX R2s are scam. But I doubt that cutter or led-tech.de sell fakes.


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## Helmut.G (Aug 5, 2008)

link: http://www.ledhilfe.de/viewtopic.php?f=14&t=5344
Actually most LED shops, including led-tech.de are unashamedly overrating their specs for all of the cheaper 5 mm LEDs and I'm sure that they would sell an Q5 bin claiming it is R2 when "all the others" do it as well
but I can't believe that e.g. the Jetbeam JET-I PRO isn't really using a R2 emitter if they claim so


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## saabluster (Aug 5, 2008)

Helmut.G said:


> I just visited the forum of a german LED shop where I hadn't been for months because CPF is so interesting. There I read that the company used their integrating sphere to measure R2 LEDs bought from other LED shops and found that they're putting out less lumens than their own Q5 ones, i.e. are _fake_.
> They also claim that they have a statement directly from Cree's "leading technicians" that R2 LEDs are only available in samples at the moment.
> This kind of shocked me as I trust this forum and it means that all the R2 things from DX and even some quality flashlights claiming R2 emitters are all scam
> can someone please tell me if thats really really true or if my post is just some kind of nonsense because I just can't believe it


JTR1962 has done testing of two R2s. One from me and one from nein166. I don't know where he got his but I got mine from Cutter. Both tested as they should to R2 specs. JTR is very meticulous and well respected for his testing. I believe it was Cutter that mentioned that the R2s are in limited release right now. They can get them but not in huge quantities and only as they yield. Here is the thread where JTR has tested them. 
Although I do get all my R2s from cutter I do in general trust DX. It is possible that they could be duped by the manufacturers who tell them what the specs are for the products. And I think it would be difficult to verify every single product they sell lives up to the specs the manufacturer says it does. Heck, you can go to Walmart and quickly find many products with overrated specs. Do I blame Walmart? No.


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## Helmut.G (Aug 5, 2008)

ok, thanks for that good info


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## znomit (Aug 5, 2008)

If R2s were that widely available there would be R3s by now. 
At least DX didn't start selling R2s immediately like they did when Q5s came out last year. Got burned there. :shakehead


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## phantom23 (Sep 19, 2008)

Dealextreme have some R2 WG. 

http://www.dealextreme.com/details.dx/sku.15943


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## metlarules (Sep 19, 2008)

I would buy a q5 as the difference between it and the r2 is at most 7%.


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## Calina (Sep 19, 2008)

For the price difference ($0.23) you might as well get the R2.


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## CampingLED (Dec 7, 2008)

Trying to use some of my R2s today (SKU 15943), without much success. Blamed my application, circuit or soldering skills, but I just need to confirm something.

I replaced an existing emitter with a trimmed R2 as well as replaced the circuit with a 1050mA 7135 driver (single 18650 battery). The light started fairly bright , but dimmed after a few seconds. Thought I had a short on the circuit and replaced it, same results. Replaced the emitter, same result. Wired an emitter directly through a 1ohm resistor, same result.:hairpull:

My questions, does the emitters have a high Vf, making them unusable in my intended application, are the emitters defective, or should I look elsewhere?

Tks


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## saabluster (Dec 7, 2008)

CampingLED said:


> Trying to use some of my R2s today (SKU 15943), without much success. Blamed my application, circuit or soldering skills, but I just need to confirm something.
> 
> I replaced an existing emitter with a trimmed R2 as well as replaced the circuit with a 1050mA 7135 driver (single 18650 battery). The light started fairly bright , but dimmed after a few seconds. Thought I had a short on the circuit and replaced it, same results. Replaced the emitter, same result. Wired an emitter directly through a 1ohm resistor, same result.:hairpull:
> 
> ...


I would look at that battery.


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## CampingLED (Dec 7, 2008)

Tried 2 x 18650 as well as CR123A, all were the same.


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## Helmut.G (Dec 7, 2008)

well, if you have tried different emitters and different batteries then it's probably the driver that doesn't work correctly
is it a buck or a boost driver?


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## blakelidge (Dec 7, 2008)

Hi,
For what it is worth, I got 12 "r2s" delivered from DX yesterday. I have no way of knowing if they truly are R2s (or anything else) as there are no determinable features on the leds or stars, however, having just finished building my first light using three of them, I can confirm they are super bright and a fantastic cool-white tint. I was also impressed that DX delivered as promised on time, so at this point I have no reason to doubt their wares (albeit, as I said, I can't qualify that I have what I paid for) Off for a ride now to try this thing out.


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## CampingLED (Dec 7, 2008)

Sorry, but tried different drivers as well. 7135's which is constant current drivers. I suspect a high Vf.


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## Helmut.G (Dec 7, 2008)

I suggest that you open a thread in the electronics forum specifically for your problem, with more detailed info about your driver
a constant current circuit should work just fine with a high Vf as that is exactly what it's supposed to do


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## CampingLED (Dec 7, 2008)

Helmut.G said:


> I suggest that you open a thread in the electronics forum specifically for your problem, with more detailed info about your driver
> a constant current circuit should work just fine with a high Vf as that is exactly what it's supposed to do


 
The 7135's are used by many CPF members, especially in P7 Mag mods and other LiIon solutions. Unfortunately it is a buck driver (very efficient though). Reason why I posted it here is because I believe that a high Vf could be the main problem and was hoping that other CPF members could verify/confirm it. 

I think the voltage drops below the Vf under load and therefore starts to dimm the emitter. During the next few days I will fist test the emitters more thoroughly with higher input voltages and other higher Vin drivers. If I was correct about the too high Vf it means extra money to buy other drivers or use more than a single cell solution than what I intended to. :shakehead


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## Helmut.G (Dec 7, 2008)

I see, a buck driver with a single Li-Ion could indeed work or not work depending on the Vf of the LED. I hope that you'll find a way to get it to eventually


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