emitter/led efficiency clarification please.

waddup · Dec 18, 2008

i see 3 major contenders.

1.seoul p4
2.cree 5
3.p7

running on lets say 2 x AA cells (direct drive)

how will these 3 perform differently?

anyone got a link to a page that covers all this already?

i have a couple cheap light laying around and a soldering iron, im thinking bout a couple 'upgrades' but want to know what im aiming for b4 i buy the emitter.

LukeA · Dec 18, 2008

They will all be very dim from 2 Alks. The P7 should be the brightest.

ergotelis · Dec 18, 2008

Well you have to read a lot more to understand some things.
Leds need from 3,2V about till 3,8V. The higher voltage the more output and consumption. They also need better heatsinking for not to burn them.
For your purpose, forget about cree q5. Go to Seoul P4 and P7, because they spread the light better for your applications. For 3xAA nimh batteries a led replacement is a nice one.

waddup · Dec 18, 2008

good try but,

i wasnt looking for recomendations, i wanted to know the differences.

i have several lights and batteries an spacers, i can mix and match the right combination once i understand more about the differences in what the emitters are designed to do.

seoul p4 is designed to ?

cree5 is ?

p7 is ?

im guessing they are all intended to output the most lumens for the least voltage?

and as technology advances they get better at doing it

so are the newest leds the best?

or are there some excellent older leds ?

is there a simple spreadsheet somewhere representing

voltage/lumen output for all the leds produced in the last 3 years?

LukeA · Dec 18, 2008

waddup said:
good try but,

i wasnt looking for recomendations, i wanted to know the differences.

i have several lights and batteries an spacers, i can mix and match the right combination once i understand more about the differences in what the emitters are designed to do.

seoul p4 is designed to ?

cree5 is ?

p7 is ?

im guessing they are all intended to output the most lumens for the least voltage?

and as technology advances they get better at doing it

so are the newest leds the best?

or are there some excellent older leds ?

is there a simple spreadsheet somewhere representing

voltage/lumen output for all the leds produced in the last 3 years?

All three LEDs use the same die, which is made by Cree.

You should buy one of the SSC LEDs because you can buy them binned for low Vf.

You can't lower a white LED's forward voltage very much. The voltage will always have to be more than 2.757V.

Marduke · Dec 18, 2008

waddup said:
good try but,

i wasnt looking for recomendations, i wanted to know the differences.

i have several lights and batteries an spacers, i can mix and match the right combination once i understand more about the differences in what the emitters are designed to do.

seoul p4 is designed to ?

cree5 is ?

p7 is ?

im guessing they are all intended to output the most lumens for the least voltage?

and as technology advances they get better at doing it

so are the newest leds the best?

or are there some excellent older leds ?

is there a simple spreadsheet somewhere representing

voltage/lumen output for all the leds produced in the last 3 years?

No, they are designed for maximum efficiency, which means the most lumens for the least amount of WATTS used, not voltage.

And yes, there is a sheet listing the various specs for the common LED's. If you bother to check the stickies in the LED forum OR use the search function, you would have seen it.

FlashCrazy · Dec 18, 2008

waddup said:
i have several lights and batteries an spacers, i can mix and match the right combination once i understand more about the differences in what the emitters are designed to do.

seoul p4 is designed to ?

cree5 is ?

p7 is ?

Cree Q5 or R2 = Sports car... Fast (lots of throw), a bit of a rough ride (may have infamous "Cree ring" around hotspot)

Seoul P4 = Sports sedan... Still sporty (good throw/spill combo), smoother ride (nice, smooth transition from hotspot to spill)

Seoul P7/Cree MC-E = Monster truck... Not so fast (decent throw), truck-like ride (harder to focus but tons of grunt, a wall of light)

waddup · Dec 18, 2008

LukeA said:
All three LEDs use the same die, which is made by Cree.

You should buy one of the SSC LEDs because you can buy them binned for low Vf.

You can't lower a white LED's forward voltage very much. The voltage will always have to be more than 2.757V.

still not clear what binned or vf is but i appreciate you help.

Marduke said:
No, they are designed for maximum efficiency, which means the most lumens for the least amount of WATTS used, not voltage.

And yes, there is a sheet listing the various specs for the common LED's. If you bother to check the stickies in the LED forum OR use the search function, you would have seen it.

sand?

FlashCrazy said:
Cree Q5 or R2 = Sports car... Fast (lots of throw), a bit of a rough ride (may have infamous "Cree ring" around hotspot)

Seoul P4 = Sports sedan... Still sporty (good throw/spill combo), smoother ride (nice, smooth transition from hotspot to spill)

Seoul P7/Cree MC-E = Monster truck... Not so fast (decent throw), truck-like ride (harder to focus but tons of grunt, a wall of light)

sweet thanks :thumbsup:

TigerhawkT3 · Dec 20, 2008

Sounds like you might want to read the Welcome Mat.

WadeF · Dec 20, 2008

TigerhawkT3 said:
Sounds like you might want to read the Welcome Mat.

+1

Also as I think Luke mentioned, the Seoul P4 (SSC P4) will probably give better results if you're modding flashlights as the beam is more forgiving with reflectors that weren't designed for a certain type of LED. Comparing the SSC P4 to the P7 would be like comparing a spot light to a flood light. In the same reflector the P4 should throw a tighter beam, while the P7 will have a floodier beam. The P7 is basically 4 P4's in one, and is capable of producing more lumens if given enough current.

emitter/led efficiency clarification please.

waddup

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LukeA

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ergotelis

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waddup

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LukeA

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Marduke

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waddup

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