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White LED experiment

  • #21
Omg yes, and have the current level control potentiometer at minimum output LOL...
I should have all the needed components in another week or so to do a smoke test ;)

The thermal glue is coming from HK.... ugh
 
  • #22
I smoked my very first 'high power' LED by getting it wrong. It was a 1W blue LED, which at the time was quite expensive. I was an electronics test technician at the time :headwall:
 
  • #23
Av,

What are you using for your constant current driver? I'm assuming it's an IC like the CAT4101 or something similar with PWM dimming since you said you're using a pot.

Have any circuit diagrams you'd share?

I'm currently running 2 3-up Endor stars at 1000mA on LM317 configured to limit current. My thermal management is overkill, so I'm not worried too much about efficiency. I'm getting around 1600 lumens at 19.2 watts.
 
  • #24
Ent.... I looked at the various options including the 317, but decided to go with a buckpack. The only local source I have is Radio Shack (rural area) and their component supply is pitiful anymore. I do have a couple PWM project circuits laying around (555 based w/pwr trans IIRC) but meh... might go down that road later.

So with the externally adjustable buckpack at under 20 bucks... well why not, with correct input voltage they can drive up to 7 rebels in series I believe (3.2vdc ea. @ 700ma)

http://www.luxdrive.com/download/?dmid=1126

Are you using passive cooling at 1000ma?, if so what is your approx heatsink surface area per watt?

I really don't want to go with fans

Av
 
  • #25
Well, I had an older one of these laying around from a PC:

www.zalman.com/ENG/product/Product_Read.asp?idx=356

Like I said...overkill. The heatsink is barely warm to the touch, even with my LM317 epoxied to it.

I get all my parts from either www.mouser.com or www.digikey.com. You can get an LM317 and the appropriate resistor(s) for less than $2 not including shipping. Led driver ICs like the CAT4101 are available for a few bucks a piece too.

Let me know how the passive cooling works for you, I plan on converting to something with a lower dB rating eventually.
 
  • #26
well that definitely has the wow factor :)
very cool.... can you post pics of your set up
 
  • #27
My first LED growlight used an LM317 as the current regulator. It was a 3 x 1W LED setup. I remember calculating the wattage dropped across the LM317 (Vin - Vout x If) and the number was quite low but I was amazed on how hot the regulator got. Initially I only had it on a small heatsink but had to re-design the lamp housing so that I could fit a larger one and a small fan!
 
  • #28
I gave the 317 serious consideration, but the buckpack came from the same source as the tristar so little to no extra shipping... plus its adjustable (at least the model i selected), 95% efficient and pretty much just "plug and play"

If I had ordered anything from a different source... after the additional shipping I would have been closer to the same price, so In my specific case it just made sense.

And no additional heatsink required.

But there are a lot of ways to skin a cat ;)

---------- Post added at 11:38 AM ---------- Previous post was at 11:36 AM ----------

Did you two do any experimentation with aux optics?
 
  • #29

Did you two do any experimentation with aux optics?
I've only made a couple of LED growlights. To be honest I haven't been too impressed with the results so far so have left it to others, like you, to exeriment with the newer stuff. My growlights were 1W red and blue Luxeon stars, so I used wide angle optics to combine the colours as close to the source as possible so that I didn't have to increase the distance between plant and light.
 
  • #30
I'm not using any optics because the widest angle ones I could find for my leds were around 20 degrees. My lights are about 1' above the plants, so for the time being I'm using polished aluminum flashing to redirect the 120 degree emittance down to around 45.

You guys might be interested in taking a peek at the led discussions going on in the reef aquarium community.

http://www.reefcentral.com/forums/forumdisplay.php?f=3

Leds have recently become the best option for corals, and there's a wealth of discussion on DIY led fixtures.
 
  • #32
Av8tor1,
What plant are you going to experiment on?
The luxeon LED's are REALLY bright.

OMG these things are bright.... I was playing around with mine for the firs time today. I was trying not to look at it too much and thought I was doing a decent job. That is until I turned it off, then I saw freaking spots everywhere LMAO.... better now but my oh my LOL

mental note, be much more careful sheesh....

trust me when I say respect these babies :hail:
 
  • #33
SingleTri-star mounted to PC heatsink with auxillary optics:
IMG_1816.JPG

I need to let it run for an extended period to be sure, but this size heatsink may be overkill

"Buckpack" driver module:
IMG_1820.JPG

No heatsinking required for it

Av

---------- Post added at 08:43 PM ---------- Previous post was at 08:07 PM ----------

Single 4000k/85CRI tristar w/ aux optics on left, 15w (60w equiv) 6500k CFL w/ reflector assembly on right.
IMG_1823.JPG

The image does not accurately convey the true intensity of the Luxeon Rebel Tristar

Av

---------- Post added at 09:04 PM ---------- Previous post was at 08:43 PM ----------

Well the heatsink is not overkill ;)
 
  • #34
Wowza those look bright! So who's the lucky guinea pig? Will you be able to mount more than one per heatsink or is the heat output too great?
 
  • #35
I dont think I would put more then one to a heatsink. After about an hour run time the heatsink is nice and warm to the touch but not hot. Maximum operating temp is 135C so there is no danger of thermal runaway with this combination.

Im not sure yet, maybe a H. pulchella division since I have a spare and already know what they look like under my T5 :)

Bright is an understatement Yann, its not anything you can look at directly!
 
  • #37
Hmmm. based on preliminary findings. Any idea what it would take to make a 4 foot light array? I am assuming power consumption is a bit less than power compact lighting (and probably less heat) and way less heat output than metal halide. Side project for Av8tor1 another garage start up company. Lighting CPs one person at a time :p
 
  • #38
Well I have no idea of how many tristars it would take yet. But based on one ever six inches, that would mean 8 of them, then 2 tristars per buckpack driver means 4 drivers, then 8 aux optics, 8 heatsinks... dc power supply, thermal glue... misc hardware and control housing

ummmm guessing $300-400ish with zero profit margin LOL

Some savings could be had by rolling your own drivers... but the additional investment in labor and the hassle would eat up most of the savings.

Cheap enough for a DIY maybe but otherwise still too expensive... but man what a light, there would be nothing like it

cold fusion for CP's LOL
 
  • #39
DIY Kits? Sort of like the AHsupply people and their compact fluorescent fixtures?
 
  • #40
I know of no "kits" for these...
 
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