DIY LEDs - The write-up
- Thread starter JohnL
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. The package says 10V. Maybe someone else can check a couple to see if they are all that high.
fstar25
Getting there
DWZM,
I have decided to go the reef keeper elite route with the ALC module for dimming control. My problem and question to you (and anybody else for that matter). The ALC module only has 2 channels and i will have 3 drivers. 2 of the drivers will be controlling the blues and can/need to be at the same level. Can I simply splice the two drivers together and run them off 1 channel? Or, are they too complex of a circuit and by connecting them you screw something up?
I have decided to go the reef keeper elite route with the ALC module for dimming control. My problem and question to you (and anybody else for that matter). The ALC module only has 2 channels and i will have 3 drivers. 2 of the drivers will be controlling the blues and can/need to be at the same level. Can I simply splice the two drivers together and run them off 1 channel? Or, are they too complex of a circuit and by connecting them you screw something up?
der_wille_zur_macht
Team RC
Yes.
In theory, you should find out how much the meanwells draw, and what the controller is capable of sourcing, and make sure that the two drivers will not draw more than the controller is capable of providing. But in practice, the drivers are likely to draw a tiny fraction of what the controller can provide, so I would imagine it won't be a problem.
It would be nice to know the numbers anyways but neither of the vendors seem interested in providing them.
fstar25
Getting there
Sad but true in too many things
Thanks for the reply. My fixture is in an open air setting on top of my canopy. I may enclose it in the future but it will definitely be getting two 120mm fans in that case. Right now it only become pleasantly warm after two hours with passive air cooling. Is "hot to the touch" uncomfortably hot right behind the LED?
Also, I only have 1/2 the LED installed right now because DealExtreme is SLOW. I think I will add a fan when the others come regardless of open air or enclosed status.
der_wille_zur_macht
Team RC
It's very hard to quantify "too hot" for a number of reasons:
1) We can't really measure junction temperature, and that's really the number that matters
2) We're all running WELL below the absolute maximum, so it becomes a question of a few percent difference in lifetime/efficiency
That said, on my own builds, I touch the star itself (NEVER the LED) or the heatsink as close to the star as I can, and if I can keep my finger there for a good 10 or 15 seconds without discomfort or pain, I'm happy. I realize that's a wildly unscientific approach, so if anyone has a more quantitative method that doesn't involve obscure measurement techniques or unreliable calculations I'd love to know about it.
kcress
New member
About 20 minutes will get your heat sink up to equilibrium.
Jay1982
New member
The distance from the top of my tank to my ceiling is 38 inches. I've decided on keeping the lights 24 inches from the surface leaving me with ~12 inches of space between the top of the fixture and the ceiling so that I can place my fan to blow across the heatsink. Will there be a spotlight effect at that height with 40 degree optics and only 25 XPGs out of 70 leds? If so I assume 60 degree optics would be in order? Or is my current plan ok?
der_wille_zur_macht
Team RC
24" above the water should be absolutely fine with 40 degree optics.
sfsuphysics
Active member
A little misleading. You want the LEDs themselves to remain cool and this is done via the heat sink. How hot your heat sink feels will vary greatly depending upon its ability to draw heat out. Typically heat sinks with thinner fins will feel quite a bit hotter than those that are pure massive ones (smaller fins), simply because less mass in the thin fins so they heat up more, however there's more surface area so the heat is easily dispersed.
Now whether or not the OP you replied to fits in the thin or the thick category is a little hard to tell from the picture. However two pieces of angled aluminum doesn't seem like terribly much mass, but its also not a thin finned one (think computer heat sinks). I might be a bit worried depending on how over driven they happen to be.
Jay1982
New member
lol, you are lighting quick today!! :dance:
Thanks man as always I appriciate your help
trentdingo
New member
So i read through 'almost' all of the posts since the beginning in search of this question but out of all that i read, didnt see it...
For simplicity reasons, would it be acceptable to use a couple of the pre-made bulb led that screw into a standard light bulb socket. I feel that if it is somewhat comparable (only slightly less lumen output per watt) it would be TONS easier to make a fixture out of these.
Heres a link to a bulb http://www.divinelighting.com/par-3...4.html?zenid=cde0d515b347e48a5d2609a2543acd3e
and as im sure you all know, nanocustoms has been marketing similar lights for a few months now.
For simplicity reasons, would it be acceptable to use a couple of the pre-made bulb led that screw into a standard light bulb socket. I feel that if it is somewhat comparable (only slightly less lumen output per watt) it would be TONS easier to make a fixture out of these.
Heres a link to a bulb http://www.divinelighting.com/par-3...4.html?zenid=cde0d515b347e48a5d2609a2543acd3e
and as im sure you all know, nanocustoms has been marketing similar lights for a few months now.
der_wille_zur_macht
Team RC
As with any pre-made product, there are advantages and drawbacks.
The advantages to screw-in luminaries like that is that they're "easy" to use. The disadvantages almost always include:
1) Poor LED choice. It might seem like a matter of "only a few lumens per watt" but the vast majority of those products use LEDs so poor that, from an efficiency standpoint, you'd be better off with MH or T5 lamps.
2) You're locked into a vendors decisions about color and optics. This might not seem significant, but products not made specifically for reefkeeping almost always have VERY poor color and optic choices.
3) You're paying out the nose to save yourself from a few hours of rewarding DIY work.
FWIW, DIY LED builds with high quality parts are typically ranging from $8 - $15 per LED used. Every single commercial fixture I've ever seen that used the right LEDs and high quality components was at least two to three times that price. I'm not interested in LEDs purely from a cost-savings perspective, but this IS the DIY forum, and in this case, you CAN save money by DIY'ing. It might seem like a lot of effort, but keep in mind that properly built, an LED fixture should last 10+ years.
Edit - thought of some more disadvantages:
1) If a component (i.e. a single LED) in one of those PAR fixtures dies, you pretty much have to toss the whole thing. If a component in a DIY fixture dies, you replace it.
2) None of those PAR luminaries give you ANY option for dimming or control.
3) I have a sneaking suspicion in addition to inefficient LED choices, many of the pre-made fixtures have inefficient drivers, thanks to packaging constraints.
4) Poor thermal management is pretty much implied - again, thanks to the packaging constraints.
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trentdingo
New member
alright thanks!... so i guess ill build one the same way that everyone else on here has been.
are we still agreeing on the buckpucks, cree XR's, at 70%, and 50/50 blue and white?
does this suffice for as sps dominant or do i have to add a few reds and greens and some lower UV wavelengths like 350-400nm?
der_wille_zur_macht
Team RC
Buckpucks or meanwells or any other driver, really.
The "best" LED right now for cool white is the Cree XP-G. In R5 bin, it's roughly 30% more efficient than Q5 bin XR-E. For royal blue, take your pick - XP-E or XR-E. XR-E have a slightly narrower distribution of light.
For ratios, it depends on personal choice. Most people would consider a 60/40 mix of royal blue to XP-G R5 cool white to be equivalent to a 15kk MH, so go from there.
Mixing in other colors - it's up to you. I don't think it's "needed" in the sense that our corals are missing anything for good growth and color, but - who knows - maybe you'll discover some new trend.
And, don't feel like you have to build one "just like everyone else." I feel like there's a ton of room for experimentation with LEDs - stuff that's not really being explored right now. But, if you DO want to deviate, do your research first, ask questions, get a second opinion, plan, test, etc.
trentdingo
New member
oh and i just though of two more questions; do you know any sites to get good deals on the needed parts? and very long time ago soundwave was mentioning about his corals having some noticeable color changes when new frags were put under led... do you know anything more about this?
was it just the zooxanthellae shifting to a more efficient photosystem or what?
was it just the zooxanthellae shifting to a more efficient photosystem or what?
der_wille_zur_macht
Team RC
The normal sites are places like:
cutter.com.au
rapidled.com
ledupply.com
and so on.
I wouldn't pretend to be enough of a biologist to explain why corals changed colors in Soundwave's tank, but it is something some other people have noticed. That said, go out into the reefkeeping community at large, and you'll notice it's extremely common for corals to color shift under different lights, even when the various lights are all "quality" and known-good.
cutter.com.au
rapidled.com
ledupply.com
and so on.
I wouldn't pretend to be enough of a biologist to explain why corals changed colors in Soundwave's tank, but it is something some other people have noticed. That said, go out into the reefkeeping community at large, and you'll notice it's extremely common for corals to color shift under different lights, even when the various lights are all "quality" and known-good.
trentdingo
New member
Im really big on analyzing light outputs of halides and i go to PSU so i usually go and see sanjay about some stuff regarding lighting. with my pretty decent biology background, I am pretty sure it is the zoox shifting to a more efficient color.
Also in my research I review data for specific photosystems in corals and the wavelengths of light that are most efficient in them. I am going to add just a few red and green led to my fixture, it will help a lot in the growth of some of my corals that use those "off" wavelengths as secondary or tertiary photosystems.
Also in my research I review data for specific photosystems in corals and the wavelengths of light that are most efficient in them. I am going to add just a few red and green led to my fixture, it will help a lot in the growth of some of my corals that use those "off" wavelengths as secondary or tertiary photosystems.
trentdingo
New member
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