Luxeon LED's?

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*o*
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Luxeon LED's?

Post by *o* » Thu Feb 22, 2007 2:16 am

Hi,

I am building a dive cannister light and i have decided to use LED's. I have heard that Luxeon LED's are pretty much the brightest you can buy but i dont know much about them...Basically i want a setup with the following parameters:

Runs of 12v or less
Has at least 2hour burn time of charge (the battery will be 10AH)
Requires moderate heat sinking (too much and it wont fit in the light head)
At least 150Lumens (i can use multiple LED's)
It can use a driver (but i don't know anything about them)

Thanks for the help!
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timmeh87
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Post by timmeh87 » Thu Feb 22, 2007 7:27 am

12v isnt really enough to short out underwater (unless its saltwater)... you could just leave it exposed instead of heat sinking it :P

luxeon III LEDs are probably your best bet, they apparently have way better looking specs than the original luxeon I, as far as price per lumen at least. (there are like 6 other product lines too, i just picked the IIIs cause they are on the main page mostly.)

they come in different colors, according to the site, the brightest one is orangeish (190 lumens). the white ones are only 80 lumens. (at 1Amp, or 60 lumens at 700mA)

you also have to choose between lambertian and side-emitter. i dont actually know the difference but id guess lambertian is what you want.

the forward voltage is about 3.7v on the white ones. so that means 4 in series, and lets say you are at 700mA, then you would need 16 of them (16x60 = 960) at 2800mA (4x700mA). (each group of 4 probably needs its own small resistor)

Code: Select all

current     lumens     time
2800        960           3.5hours
4000        1280         2.5hours
anyways, i just went though this quickly. it looks like it will end up costing you about $40 for the lights, but apparently digikey does not carry them :(
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Post by Ari » Thu Feb 22, 2007 9:34 pm

Get a cree X-lamp instead. It's 176 lumens at one amp (4 watts). That's brighter than a Luxeon V with lower power consuption, and therefore less heat. Though I'm not sure how much heatsinking you'd need for it. I have a Luxeon III flashlight (maglite) that has a really small heatsink that overheats if left on over 15 minutes and starts to dim. But they really don't make too much heat. Maybe an old pentium heatsink would work...
http://www.cree.com/products/xlamp7090_xre.asp
You can request a sample from there.

I made a Luxeon flashlight once, with a luxeon 1... but it just used a resistor and a few AAs.

If you want a place to buy Luxeons and drivers, check out http://www.ledsupply.com/ .
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Post by *o* » Fri Feb 23, 2007 2:57 am

that sounds good...the cree x-lamp sounds pretty much perfect!

what voltage does the x-lamp run on? is it 3.7v?

so if i use a 7.2v 10AH power supply made of 6 D size rechargeable batteries would that work with 4 x-lamps arranged with 2 sets of 2 so i have a total of 5 leds with *thinks* a lot of lumens?
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Post by timmeh87 » Fri Feb 23, 2007 8:57 am

2x2=5 now?
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Post by *o* » Sat Feb 24, 2007 5:42 am

i was very tired when i wrote it...

what i meant was a total of 4 led's would that work?
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