DIY LEDs - The write-up

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stugray said:
...

The thermal engineer claimed is was one of the best thermal conductors.

...

Stu
Click to expand...

Interesting, since like the post above, I have silicone hot pads and oven gloves that are very resistant to heat transfer. I wonder if that 'red' silicone contains other substances besides silicone to get a larger heat transfer. In any case, it doesn't seem like a silicone based glue would be as good as other alternatives.
 
widmer said:
In my thread, I have a shot of the beam cast on the ceiling as well, and in the picture it looks just like the beam he's posted, but in real life there's not an absolutely perfect blend of the b/w beams. At least in my case, the picture is a minor misrepresentation...
Click to expand...

oh ok..
that makes more sense. In the pic, it looks like a single beam from a flashlight...
-R
 
schnitm said:
That's what worries me. I'm planning on 6 XP-Gs and 12 XR-E RBs in a spot the size in my picture. I think I want 300+ PAR but I don't really want 800 PAR do I?

I know, buy a meter.
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I wouldn't worry at all. For one, a reading like a PAR number taken under a fixture like that doesn't tell the whole story. You will likely only get numbers like that when taking readings in a limited number of positions. Namely, the middle, and facing straight up.

If you just made another fixture like the one you have and put them side by side, you'd get more intensity in the center but wouldn't really get that much better coverage per-se. I'm assuming since they are 13deg optics that this fixture will be 4-6 feet from the tank???

IMO in that scenario what you should do is move the two fixtures apart and angle them towards the tank center, even possibly going as far as Santoki did for his longer tank. This way you still get roughly those same peak PAR numbers you want (maybe a bit brighter where they overlap), but you will achieve them from more angles inside of the tank, not just oriented straight up in the center. This is what leads to more vibrant coral tissue oriented towards the viewer. You see this in japanese tanks alot. Also this way you don't end up with a 'pyramid' of coral growth as corals grow to the central hotspot. It will look more natural with light hitting from different angles.

I'd love to see somebody put a tiny fixture like you did on a mover for a nano. The reason corals in the wild sometimes grow differently is that the sun is always moving and illuminating different parts of the coral branches. In alot of reef tanks there are shaded regions on coral branches and this can alter the way they grow and less vibrant tissue is visible.
 
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Obi-dad said:
Interesting, since like the post above, I have silicone hot pads and oven gloves that are very resistant to heat transfer. I wonder if that 'red' silicone contains other substances besides silicone to get a larger heat transfer. In any case, it doesn't seem like a silicone based glue would be as good as other alternatives.
Click to expand...


maybe he meant one of the best thermal insulators
 
LEDs are cheap at:

dealextreme.com (but stock status and shipping are questionable)
rapidled.com
nanotuners.com
cutter.com.au (who I'll probably use for my 360g's rig - best combo of service, selection, etc.)

Meanwells? Who knows. Seems like no one can keep them in stock. If you want to pretend to be a commercial entity (instead of a hobbyist) then powergatellc.com might be the best bet.
 
schnitm said:
Can we estimate PAR?

This spot is approximately 14" wide, just a bit more than 1 square foot.

LEDSpot.jpg


It's made by 3 Cree XP-G 6500K and 3 Cree XP-E Royal Blue with optics running at 1000ma. Just considering the whites there's about 1050 lumens there. If the optics get 80% (?) into the spot there are around 800 lumens there + whatever the blues contribute.

This (http://www.thekrib.com/Plants/Tech/par-moles.html) seems to suggest that PAR is close to 0.02 x lux. So:

800 lumens/ft = 8000 lux = 160 PAR.

Seem reasonable, Can we guestimate PAR like this? How far off am I likely to be and am I under or over?
Click to expand...

There is no reliable way to convert lux to PAR. Lux looks at a very narrow band of light while PAR is a range. If you have light that is very weak in the 555nm (lux reading) range you would have a low lux reading but might have pretty good PAR. If I had to guess based on what the LED's have in the range of light I would guess your 160 PAR estimate is low.
 
der_wille_zur_macht said:
LEDs are cheap at:

dealextreme.com (but stock status and shipping are questionable)
rapidled.com
nanotuners.com
cutter.com.au (who I'll probably use for my 360g's rig - best combo of service, selection, etc.)

Meanwells? Who knows. Seems like no one can keep them in stock. If you want to pretend to be a commercial entity (instead of a hobbyist) then powergatellc.com might be the best bet.
Click to expand...

Thanks.
 
I just made a purchase the other day - etgtech.com for the LED and powergatellc.com for the meanwells (27.42 each, but backordered till 4/7)
 
I'll second the rapid LED for the drivers, I didn't mind paying more since they had them.

I would like to add WOOOOOT !!! Mail man just knocked on the door with two packages, the international shipping required a signature
picture.php


With the thread search down, I am going to ask something that has been covered. I am off to fry's for the rest of my parts and a new soldering iron. I assume Flux-core solder will work, Can anyone chime in?
 
sahin said:
OK people, I have a JBJ 28 NC with the 150w halide. I have already retrofit 8 Cree RBlue running at 700mA. I have ordered 8 more in order to get a bluer colour and to boost the PAR in the tank.

I love the actinic pop but also want more PAR, here is why:

After I put SPS corals in my tank they start to lose colour. I have accounted for water chemistry, transportation of corals etc, but still losing colour.

I then placed the corals higher up in the tank and they start to colour up again. I cannot put all the SPS at the top half of the tank, so need to ramp up lighting.

I am only using the Cree Royal Blues because I want a bluer colour etc.

So do you think running 16 CREE RB LEDs at 700mA with a 150w MH Phoenix bulb will get me close to a 250w halides "power"/PAR?

I will be placing the 16 LED's around the perimeter of the halide and will use 80 degree optics in certain places and the side etc.

Appreciate responses especially from the LED pioneers of this thread. Many thanks.
Click to expand...

Can anyone please answer the above/make some comments. Thank you. :cool:
 
You didn't mention if your leds have optics yet. Key info.

Sounds me me like a 150w halide and 16 LEDs should be plenty.... then again a 150w and 8 LEDs also sounds like plenty with the right optics. Even if you are keeping inside the tiny hood of the JBJ you might want to try 60 degree optics.
 
I'm building the LED's into the stock canopy, so they will sit abo 2inches above the water, hence I wont be using optics, except for the sides where i will use 80 degre optics to keep light spill minimum.
 
If you want PAR you might want to mix some cool whites in there too, since they're more efficient in terms of absolute output.

Though, I suspect you might want to investigate further before increasing a single narrow spectrum of light. More PAR might mean more growth, but it won't inherently mean more color.
 
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