DIY LEDs - The write-up

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Sammy, when they're off are they 100% physically isolated from any power source? i.e. unplugged?

Also, how are you dimming them? I've noticed on some drivers that if the dimming circuit is powered while the main circuit is completely disconnected (i.e. unplugged or physically switched off with a mechanical relay), you'll get a very small current "leaking" through the dim circuit and powering the LEDs. I don't know enough about circuit design to understand how or why this happens, but I have observed it as well.
 
Is anyone going with Cree XP-Gs yet I noticed AI is shipping their new fixtures with these LEDs and I see Digikey has them for sale $9.00 per LED has anyone seen them anywhere else?
 
Cutter out of Australia has them, I think around $6/ea mounted on stars. I'm willing to bet that ETG and some of the other big outfits in the US have them or can get them, but I haven't tried to find out yet.

I'll be starting on the build for my 360 in 3 or 4 months - at that point if the XP-G are available and under $6/ea I'll probably use them. (For the whites at least - they're not available in blue or royal blue that I know of.)
 
Wavelength they peak at is different. Think of the difference between an actinic fluorescent lamp and a plain old "blue" one. The Royal color is a little more like an actinic lamp (a very deep purple-blue) vs. the blue LED looking more like a solid medium-blue.

True actinic peaks at 420nm, while royal blue XR-E's are around 450nm and blues around 480nm, iirc.

EDIT - if you're just starting out on a fixture I'd suggest ordering a few of each and a few cool whites, then play with different combos to get the color you want - BEFORE ordering the motherload with the assumption that you can just tweak the dimmers to get a certain color. Since (colored) LEDs typically peak in a very narrow spectrum and have NO output anywhere else, it's impossible to get some "looks" in your tank unless you have the right LEDs to start with, even if you can dim different colors individually.

Personally, I like the royals for "glow" during dawn/dusk but the blues to create a cool noontime daylight color. I think my rig will likely have a bunch of royal blues on their own dedicated drivers, then a mix of cool white and blue on the "daylight" drivers. I'll treat the royals like actinic accent lighting, and the cool white/blue combo like a 10kk daylight lamp.
 
Trying to finalize plans for an LED array in my friend's Fluval Edge 6gal tank. He would like to keep the stock hood, that the 2 halogen bulbs hang in, looking unmodified. He only plans to keep mostly mushrooms and polyps along with maybe a few leathers.

To do this, I think I could angle the LEDs so instead of pointing straight down they angle towards the far side of the tank. So LEDs on the right side of the hood point towards the bottom left of the tank and vice versa. I think I can get away with probably 4-6 LEDs total, a 50/50 mix of CREE XR-E Q5 Cool Whites and XR-E Royal Blues mounted on small PC heatsinks with a 90mm as exhaust out the top of the hood.

What angle optics do you think will be needed so I can angle some light that would spill out of the hood back down into the tank but still prevent a dark zone in the center of the tank? 60 deg? maybe 40deg?
 
Scale your plans down by about 200%. A 6g is TINY. I would use no optics (or 80's if you really want them). 4 LEDs max, and run at 500 or 350mA. Mushrooms are usually pretty low-light and in a tank that shallow it's going to be hard to tone things down enough.
 
Sammy, when they're off are they 100% physically isolated from any power source? i.e. unplugged?

Also, how are you dimming them? I've noticed on some drivers that if the dimming circuit is powered while the main circuit is completely disconnected (i.e. unplugged or physically switched off with a mechanical relay), you'll get a very small current "leaking" through the dim circuit and powering the LEDs. I don't know enough about circuit design to understand how or why this happens, but I have observed it as well.

They still plugged in to the digital timer. The timer has two slots to plug stuff so I plugged the meanwells (Both drivers share the same power cord) and the 10V wall wart (cause I didn't knew if it was a good idea to leave it plugged while the lights are off. I just tested what happened if I turn off the lights and unplug the 10V wall wart and nothing happened. They all still dimmed on. Now if I turn on with the wall wart unplugged the white will turn on (not at 100% the blues remain dimmed almost Off and when I turn the whole thing off, the whites dim from low to high like a flash and then right after them the blues do the same. Looks like a light sample very cool though lol
 
There may be caps somewhere on the output side that are staying charged enough to light the LEDs - I've seen that happen too, though it usually bleeds them dry after a few minutes.
 
Was definitely planning on only running the LEDs at 350mA. Should have mentioned that in my previous post. I think 4 LEDs will do.

My main goal with optics was to angle back into the tank some of the light that would be spilling onto the walls of the hood. I think I may have underestimated the intensity of these lights and won't use optics to start.
 
Scale your plans down by about 200%. A 6g is TINY. I would use no optics (or 80's if you really want them). 4 LEDs max, and run at 500 or 350mA. Mushrooms are usually pretty low-light and in a tank that shallow it's going to be hard to tone things down enough.

I don't think 4 LEDs will give the right coverage for that tank. 6 seems good to me. Anyway you will have a spot light in the center and dark corners. I'd say go with no optics, 700mA buckpuck WITH POTENTIOMETER cause you may want to dim a little. It doesn't look overkill to me. Take a look at that nano board which has a huge variety of builds for tanks this small. You won't see anything lower than 6 LEDs and tanks go as little as 3 gallons
just my 2 cents
 
Is there a recap of what I would need in order to build something for moonlight effect on a 300 and also lighting for a nano? There are just too many pages to scroll through and I also wonder if some of the stuff talked about in the earlier pages have changed in terms of availability and technological improvements. Thanks in advance.
 
I don't think 4 LEDs will give the right coverage for that tank. 6 seems good to me. Anyway you will have a spot light in the center and dark corners. I'd say go with no optics, 700mA buckpuck WITH POTENTIOMETER cause you may want to dim a little. It doesn't look overkill to me. Take a look at that nano board which has a huge variety of builds for tanks this small. You won't see anything lower than 6 LEDs and tanks go as little as 3 gallons
just my 2 cents


Fair argument. My experimentations on small tanks have shown that the typical nano-sized builds are generally too powerful, but I'm sure others have had other results, or else they wouldn't keep building them that way. :D
 
Is there a recap of what I would need in order to build something for moonlight effect on a 300 and also lighting for a nano? There are just too many pages to scroll through and I also wonder if some of the stuff talked about in the earlier pages have changed in terms of availability and technological improvements. Thanks in advance.

Kenny, you're in luck. Moonlights for large tanks AND nano-sized builds have both been discussed on this very page of the thread. :lol: If you have specific questions, please ask.
 
I did read through what was quoted in the second post on this page but didn't understand very much of it :o

Here is basically what I am trying to do.

1) Moonlights for the 300. Footprint is 6'x3' with a depth of 27". It's open top with a light rack and no canopy. Which bulbs and how many would I need? You mentioned a fan is needed to cool the LEDs. Is that true for the moonlight types also? I ask b/c it would be difficult to attache any type of fans to the light rack. Would it be ok if it's not enclosed? I am sure there are many more questions and probably many that are pertinent I would need to ask first.

2) Lighting for a nano. Footprint is 18"x12" and a depth of 14". This is basically a QT tank for fish and corals. What would the requirements be here? Thanks.
 
I did read through what was quoted in the second post on this page but didn't understand very much of it :o

Here is basically what I am trying to do.

1) Moonlights for the 300. Footprint is 6'x3' with a depth of 27". It's open top with a light rack and no canopy. Which bulbs and how many would I need? You mentioned a fan is needed to cool the LEDs. Is that true for the moonlight types also? I ask b/c it would be difficult to attache any type of fans to the light rack. Would it be ok if it's not enclosed? I am sure there are many more questions and probably many that are pertinent I would need to ask first.

With a tank that big, I'd probably get ~6 Rebels (they have a wider field of view than XR-E) in your favorite color, and run them on a dimmable 350mA buckpuck. You'll need a DC power supply to run the buckpuck - a 500mA or greater 24v wall wart would work. At these low currents, you don't need a fan if the heatsinks are big enough, especially since you'll be spreading the LEDs out apart from eachother. You could use PC processor heatsinks. No worries about having the LEDs enclosed - they're better off with good ventilation. Use an acrylic splash shield to protect them from spray from the tank.

2) Lighting for a nano. Footprint is 18"x12" and a depth of 14". This is basically a QT tank for fish and corals. What would the requirements be here? Thanks.

On this tank I'd probably either do three buckpucks (for 18 LEDs) or two Meanwells (for 24 LEDs). I'd do dimmable 700mA or 500mA for a drive current. When you have fish in the tank, might as well run lower light or only one string. With corals, you can use the dimmers to simulate the correct lighting for the particular corals.
 
I did my best to read go through this entire thread. Very interesting. I wish I wouldn't have just purchases those 2 MH ballast recently. I should be making one of these! Also I didn't hear anyone mention to polishing the bottom side of the heat sinks to allow more light transfer.
 
LEDs generate linear light. that means the light is pretty much all going in one direction (not strictly true but the angles of dispersion ore greatly diminished when compared to more traditional lighting methods) the result is not a lot of light is hitting the heatsink to be reflected back or absorbed.

I did my best to read go through this entire thread. Very interesting. I wish I wouldn't have just purchases those 2 MH ballast recently. I should be making one of these! Also I didn't hear anyone mention to polishing the bottom side of the heat sinks to allow more light transfer.
 
I did my best to read go through this entire thread. Very interesting. I wish I wouldn't have just purchases those 2 MH ballast recently. I should be making one of these! Also I didn't hear anyone mention to polishing the bottom side of the heat sinks to allow more light transfer.

no need....LED light radiates mostly straight out of the LED with a small portion outward up to the 180 degree horizontal plane of the star it is mounted on. optics can be used to reflect the horizontal "spill" downward as well, so polishing would be wasted effort for the benefits to trouble ratio LOL
 
I can't see using these LEDs as moon lights being that great. They're too bright, you'll end up dimming them. If that's the case, why not just purchase a cheaper LED setup to do the job?
 
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