What are the LED bulbs to look for in a AA light?

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vivid

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Please explain Cree LED model numbers.

I am looking to make my first purchase into a nicer AA sized flash light. I notice nearly all brands use a version of the Cree LED but I am a little confused by the model numbers.

Many use XP-E or XR-E, am I right in saying that this part refer to the form factor of the LED? XP-E is smaller than XR-E?

After that there is a letter and number such as R2, Q5, Q3 or P4, does the letter refer to the version/series within the size (XP-E or XR-E) usually later bulbs have increased efficiency and the number refers to the light output?

Then there some list a WC, WD or A5, does this then refer to the color temp of the output?

Any pointers would be of great help. As a noob this is one area that I have found little reading on within help pages.
 
Re: Please explain Cree LED model numbers.

This is from my undestanding:

X is for a single die LED, M is for a multi die LED. The next letter seem to do with the packaging. P is the small package, R is the larger package with the silver ring, C is for the multidie package. The last letter has to do with the die size. E is a 1mm^2 die, C is a smaller die, and G is the 2mm^2 die.

P4, Q2, R5, N3, are all flux bins, output ratings.

The WC, 5A, and so on are tint bins.

The LED section could be helpful.
 
Re: Please explain Cree LED model numbers.

thanks for you help, but I think I will just post in the LED section... Some of the threads linked to, I'm sure, are full of information but I don't really have the basics to understand some of it.
 
Re: Please explain Cree LED model numbers.

when you say the "welcome mat" are you referring to the stickie at the top of this section? If so I have read several of those post including carrots excellent "guide to high-end lights"

I have not really found a thread that explains the emitter model numbers nor what are the latest emitters. I'm sure there are threads that go over the topic but as someone who knows very little about flashlights (I only really started reading about them a few days ago) I'm struggling to understand what the difference between emitter models are, in basic terms.

Maybe if I set out the purpose of this thread it will make it easier to understand my goal. I want to buy a couple of AA LED ~$50 lights. I would hate to spend that much on a light just to find out I bought a bulb that was the last generation when another respected manufacture had a flashlight with the latest emitter for about the same price.

sorry if I being a pain and thanks for the help.
 
Re: Please explain Cree LED model numbers.

vivid said:
when you say the "welcome mat" are you referring to the stickie at the top of this section? If so I have read several of those post including carrots excellent "guide to high-end lights"
Click to expand...

No, I mean the "Welcome Mat", stickied and linked all over the forum.
 
I posted this thread (quoted below) in the general section and was recommended to post in the LED section. My goal is to figure out which are the newer and more efficient bulbs used in AA LED flashlights by understanding how cree labels their LEDs. At first I thought it was fairly simple but from some of the responses I think there may but a little more to it than I first thought.

Without going into too much detail what are the LEDs I should look for in a multi-purpose AA powered light. Nearly all brands talked about here use Cree emitters but have one or two letter different like XR-E or XP-E followed by an R2, P4, Q5 etc. I don't know the difference and would hate to buy a light with last years model emitter in it.

any help would be great.

vivid said:
I am looking to make my first purchase into a nicer AA sized flash light. I notice nearly all brands use a version of the Cree LED but I am a little confused by the model numbers.

Many use XP-E or XR-E, am I right in saying that this part refer to the form factor of the LED? XP-E is smaller than XR-E?

After that there is a letter and number such as R2, Q5, Q3 or P4, does the letter refer to the version/series within the size (XP-E or XR-E) usually later bulbs have increased efficiency and the number refers to the light output?

Then there some list a WC, WD or A5, does this then refer to the color temp of the output?

Any pointers would be of great help. As a noob this is one area that I have found little reading on within help pages.
Click to expand...
 
Re: Please explain Cree LED model numbers.

XR-E is still used alot, but the XP-E is newer. R2 is one of the newer bins, then the Q5 is next. Most of this is overwhelming to a newbie. I use to follow closely, but I still get confused if I don't stay up to date.
vivid said:
I am looking to make my first purchase into a nicer AA sized flash light. I notice nearly all brands use a version of the Cree LED but I am a little confused by the model numbers.

Many use XP-E or XR-E, am I right in saying that this part refer to the form factor of the LED? XP-E is smaller than XR-E?

After that there is a letter and number such as R2, Q5, Q3 or P4, does the letter refer to the version/series within the size (XP-E or XR-E) usually later bulbs have increased efficiency and the number refers to the light output?

Then there some list a WC, WD or A5, does this then refer to the color temp of the output?

Any pointers would be of great help. As a noob this is one area that I have found little reading on within help pages.
Click to expand...
 
Re: Please explain Cree LED model numbers.

Marduke,
thanks for that link, looks like some good info that I must take some time to read. Its a step more technical than Carrots guide and has added a piece to my understanding of Cree emitters already.

FlashKat,
thank you very much. That was very helpful.
 
Last edited:
hi vivid,

I gather that you already figured out that Cree is at the moment undisputed leader in power LED efficiency.

There are basically 3 different variables in a Cree LED:

  1. Package
  2. Flux bin
  3. Tint


'Package' is just in which physical enclosing the die[1] is in.

  • XR-E is the 'classical' packaging
  • XP-E is a smaller version of the XR-E (same die size), which is beneficial for reflector design (more throw with same reflector size possible). Also, with the XR-E the flashlight designers had to be wary about the so called 'Cree rings' (make a search here if you want to know more)
  • XP-G is the newest package. It has a larger die than the XP-E, this means that its capable of more total output. Also is generally more efficient than the XP-Es. But larger die size means its harder to achieve the same throw as with the XP-E
  • MC-E are just four XP-E-sized dies in a package. Very floody, and of course 4 times as bright as a single XP-E. Not used much in AAs because of it's size and power requirements

'Flux bin'
This is the efficiency of the die. A letter higher up in the alphabet means higher efficiency (and this in turn means brighter lights with same runtime). The number after the letter is a further division of the efficiency - e.g. a R2 is more efficient as a Q5, and a R5 is more efficient as a R2. You can get a table with all of Crees flux bins at [2]


'Tint'
This is the color of the LED. First a bit of theory about white LEDs: basically a white LED is just a blue LED with a phosphor coating. This coating absorbs some of the blue light and in turn emits yellow to red colored light. Go to [3] for a nice graph of the emitted spectrum and more info.
The reason why many LEDs have a rather blueish tint is efficiency. I mentioned 'absorbing' - yep, that phosphor is making the output dimmer, as it absorbs far more than it emits again. So there are warm white LEDs which closely match the spectrum of an incandescent light, but they are always dimmer than cool white LEDs. For example, the 4sevens Quark light have flux bin of R5 for the cool white LEDs, and only Q3 for the warm whites (that's only about 2/3 of the output). For a full list of different tints, have again a look at [2].
Common cool white tints are WC/WD/WG, and 5A/5B are common warm white tints.


[1] http://en.wikipedia.org/wiki/Die_(integrated_circuit)
[2] http://www.cree.com/products/pdf/XLampXP_B&L.pdf
[3] http://en.wikipedia.org/wiki/Light-emitting_diode#Phosphor_based_LEDs
 
Balu,

that is absolutely amazing, thank you. Your post above should be incorporated into the "welcome mat"
 
You could have just asked a moderator to move your old thread, which already had a lot of solid information in it, to the LED section. No need to create a whole new thread on the same subject. Multiple threads by the same person on the same subject tend to clog the search function, and slow down the forums unnecessarily.

Not to yell, but they told you basically the same thing in the other thread.

Also, LED's are not bulbs, in the traditional sense. They are a solid state light emitting diode that produces light in a particular wavelength. A bulb can just be plugged into a circuit, LEDs require a driver, or some sort of resistor to reduce current flow to the LED.
 
John,

you're right, I should have asked for that thread to have been moved here, and I should have known better, sorry. Having spent good amount of reading about it today and then going back and re-reading the other thread there was indeed a good amount of info in there too but at the time I needed it to be dumbed down a little.

But thanks to all of those that helped.
 
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