Which red leds is everyone buying?

Hi,
I'm installing some Cree XML2 chips on an aluminum tube.. I need to increase the sum of the forward voltages of my series setup and figure I may as well add a few red leds to the array.

So, I ask.. Which model red are you folks using? Is there a specific chip I should look at?

Thanks,

my blackstar 240w had Red: 630, 660nm 3 w each

Specific chip? depends on the specs you are looking for.
Cree XP-E
Cree XB-D
Osram Rebel

Look for members Supra SPL and Goud in the DIY threads, they live and breath this stuff.

Luxeon ES deep red EX6 bin available on stars at StevesLEDs
Oslon SSL hyper red (deep red) 3T or 4T bin. Available on stars at ISLED last I checked
Cree XPe or XPe2 630nm red P3 bin available on stars at LEDGroupbuy and Cutter

good luck!

^^ I JUST gave you rep supe.... how can I even keep up!? Seriously, you have to be one of the most resourceful guy's I know, thank you. again and again.

So. if you had to break it down and choose.. which is more efficient? Which is most cost effective? (No I havent looked at em yet..i know..)

the ssl and xpe2's are gut instinct, but so was buying my first 90w ufo

goin to look now, again, thank you for EVERYTHING youve contributed to the comm.

TNX Scotch At 700mA Tj 50C here is how they stack up:

Luxeon ES EX6 38.4%
Oslon SSL 3T 39.3%
XPE P3 42.2% (High thermal resistance 10C/W)
XPE2 P3 38.1% (Better thermal resistance 5C/W but worse temp droop)

Any of these make a great choice. Unless you are in Europe, the Oslon SSL can be expensive to source.

What is BIN? You guys keep mentioning this.. what is it and why is it important?

Is this like a "LOT" number to track production runs?

When LEDs are manufactured there are differences in color, vF and efficiency. The bin describes these differences and of course efficiency is the one that gets the most attention. You can decipher what the bin codes mean by looking over the spec sheet.

SupraSPL said:

TNX Scotch At 700mA Tj 50C here is how they stack up: Luxeon ES EX6 38.4% Oslon SSL 3T 39.3% XPE P3 42.2% (High thermal resistance 10C/W) XPE2 P3 38.1% (Better thermal resistance 5C/W but worse temp droop) Any of these make a great choice. Unless you are in Europe, the Oslon SSL can be expensive to source.

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Gotta agree with Scotch, Supra has been the biggest influence and help on my build too. Did you measure and estimate those values yourself? Because pct.cree.com offers these values at 50C 700mA: XPE P3: 115.6lm, 1.6W XPE-2 P3 122.6lm, 1.68W Both seem to have similar W/lumen ratios, so shouldn't they be similarly efficient? Tho I wouldn't be surprised if the real world performance of XPE-2 is worse.

Supra -
I think maybe I'm just beginning to understand some of this. Can you take a look at the attachment, if it attached and if it's legible?



This is a screenshot off a Cree .pdf. I googled "cree xpe p3" and this was the second hit.

If the link to the .pdf works, please scroll down to Page 5. Bottom of Page 5 is the chart that I attached. I used GIMP to tweak it a little. Can you verify? R3 refers to spectrum, and P3 refers to binning? They don't call it binning, which would be awfully helpful, but the flux is highest and I think flux means light.

Notice that the flux is determined @ 350mA. anomuumi makes mention of 700mA readings in the post above mine. Not sure which cree .pdf he got that from?

Hi Mellodarama! Yes, you are absolutely right. I used this Cree calculator for my numbers: http://pct.cree.com/dt/index.html

anomuumi said:

Gotta agree with Scotch, Supra has been the biggest influence and help on my build too. Did you measure and estimate those values yourself? Because pct.cree.com offers these values at 50C 700mA: XPE P3: 115.6lm, 1.6W XPE-2 P3 122.6lm, 1.68W Both seem to have similar W/lumen ratios, so shouldn't they be similarly efficient? Tho I wouldn't be surprised if the real world performance of XPE-2 is worse.

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Yes I have been getting these numbers from my own spreadsheets (with some help from Mr Flux for LER). You are correct regarding the output. The catch is, the XPE has a vF of 2.21 and the XPE2 has a vF of 2.39 so the XPE2 would be dissipating more power than the XPE. I will have to look at your source though because my sheets (based on the Cree spec sheet) say the XPE creates 121lm so I wonder how they get 115? The vF also disagrees.

The cool thing is the XPE2 is supposed to offer a P4 bin.

Yep mello you got it, that is the flux bin. I have had to extrapolate the output at 700mA and adjust for the junction temp because they often assume 25C or 85C but I try to run at 50C. I havent tried the tool ano linked to but I am going to check it out.

Thanks for the info everyone..

One more question.. where are cree chips made? There's an ebay seller who has them here:
http://www.ebay.com/itm/5PCS-Cree-XLamp-XP-E-Red-620-630NM-1W-3W-LED-Light-Emitter-w-20mm-Star-Base-/321100795689

Is this a scam? or are these legit cree leds..?

Cree does manufacture some chips in China and those do look legit. The auction you linked does not specify the bin so you should assume it is a low. For slightly more $ you can get a top bin from Cutter.

Legit XPE red for reference

SupraSPL said:

Cree does manufacture some chips in China and those do look legit. The auction you linked does not specify the bin so you should assume it is a low. For slightly more $ you can get a top bin from Cutter.

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Thanks.. I'm just growing some veggies.. mostly using the neutral white XML2 chips.. Only ordered four of them to start off and thought I might add a few reds to bring up my forward voltage sum a bit to match power supply.

Not a bad idea

SupraSPL said:

Not a bad idea

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LOL. You mean the part where you told me which chip to use? You couldn't have made it any easier if you had copied and pasted a Buy-It-Now button into your post.

Hey I was wondering which meanwell driver I would use to run the cree xpe chips?

Madgrower84$ said:

Hey I was wondering which meanwell driver I would use to run the cree xpe chips?

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