Input requested on DIY LED build

[joshlawless]

I'm finalizing plans for my 72Wx33Dx40T tank build, and want to DIY my lights to get the most control over color and placement. Here's what I've come up with so far, and I'd appreciate anyone with more XP chiming in if they see me making some stupid mistakes.

Here's the top of the tank, and how I want to organize the fixtures:

There's an 18" MakersLED heat sink on either side of the tank, perpendicular to the length of the tank, and tilted around 15 degrees toward the center of the tank.

There's two 36" MakersLED heat sinks in the middle of the tank, with the front fixture being tilted 15 degrees toward the back.

For each 18" fixture, there will be five channels, each running off of a Meanwell LDD-700H driver. A 180W 48v 3.75A power supply will power the fixture. The channels will include the following LEDs:

White channel: 7x CREE XT-E cool white + the 7 neutral white diodes on 7x CREE XT-E 3-UPS.
Royal blue channel: The 14 RB diodes on the same 7x CREE XT-E 3-UPS.
UV/Violet channel: 1x Exotic 405nm, 1x Exotic 430nm
Cyan/Blue channel: 1x Exotic 475nm, 1x Exotic 495nm
Red channel: 1x Exotic 660nm, 2x Exotic 730nm (in parallel, to drop the current from 700 mA to 350 mA)

For the 36" fixtures, I thought I'd just double everything from the 18" fixture
(e.g., two LDD-700H white strings, two LDD-700H royal blue strings, and twice the diodes on each of the colored strings, still with 1x LDD-700H each). For these, I'd need a slightly larger power supply, but with only 7x LDD-700H, I should get away with the 250W version. I might fully populate the lines of colored LEDS (e.g., 6 or 7 blues and 6 or 7 violets, instead of 4), so I could run them a little lower, but still have some fun with red night lighting or heavy UV for photography.

I haven't worked out what optics to use, or how high to mount them, but how does this sound at first blush?

 

[joshlawless]

Whoops, meant to say that the side fixtures were 24", not 18"

 

[joshlawless]

So, a little work in the layout program, and I've come up with these numbers:

White channel:
-- 6x Meanwell LDD-700 driving
---- 42x 700mA CREE XP-G Neutral White emitters (from the 42x 3-UP star)
---- 48x 700mA CREE XT-E Cool White stars
Royal Blue channel:
-- 6x Meanwell LDD-700 driving
---- 84x 700mA CREE XT-E Royal Blue emitters (from the 42x 3-UP stars)
UV channel:
-- 4x Meanwell LDD-500 driving
---- 20x 500mA Exotic True Violet stars
---- 22x 500mA Exotic Hyper Violet stars
Cyan/Blue channel:
-- 2x Meanwell LDD-500 and 2x Meanwell LDD-1000 driving
---- 22x 700mA Exotic Turquoise stars (driven at 500mA)
---- 20x 700mA Exotic Cool Blue stars (driven at 500mA)
Red channel:
-- 5x Meanwell LDD-700 driving
---- 24x 400mA Exotic Hyper Red stars (driven at 350mA)
---- 22x 700mA Exotic Deep Red stars

While that may seem like overkill with the numbers of colored LEDs, I wanted to have enough stars to provide even illumination over the tank -- I'll just run them dimmed way down to keep it from looking like a blue/green/uv mess.

For the Turquoise and Blue stars, the LDD-500 will drive them in series on the smaller fixtures, and the LDD-1000 will drive them in a series of parallel pairs, to keep the drive current on each star at 500mA, and reduce the damage that a burnt-out star can do:

Similarly, with the red channel, I'll the Hyper Red have a max drive current of 400 mA, so I'll run them in parallel pairs, wired in series, mixed with the Deep red, on the LDD-700 string (running them in parallel will provide each with 350mA).

My concern is whether this will be enough white and royal blue -- the others I can turn down.

 

[joshlawless]

To clarify - I think that running parallel pairs in series like this will limit the damage that burnt out star can do, because if one star in a pair burns out (breaks that sub-circuit), then all of the current coming from the driver will pass through the remaining star in the pair, quickly burning it out, too, like a fuse, protecting the rest of the stars connected to the same driver. Not that they even need protection - they're still going to be running in parallel, given that the line ties together between every pair (so only the star next to the burned out star will ever see a 1000mA drive current).

This strikes me as better than running entire strings of LEDs in parallel, where one whole string can burn out if a single star on a parallel string burns out.

Anyone who can tell me if my understanding isn't correct will be very much appreciated!

 

[joshlawless]

Here's the proposed layout (remember, those colors are going to be dimmed way down):

 

[DoitCheap13]

I'm gonna follow this!

 

[asid61]

1. I think it would be safer to just run them in series, especially if you are going with LDD drivers. I can't be sure if your idea won't work, as it sounds pretty plausible. But to err on the side of caution is good.
2. You want to run only two 72" heatsinks over the tank. I don't think it will look as nice if you run the 4-heatsink setup you have now. You can stick with what you want, but JMO.
3. IMO, ditch the cool whites in favor of some royals and neutrals in a 2:1 ratio of RB:NW. Cool whites won't add anything to your setup.
4. Run 1000HW drivers on the royals and neutrals and dim them down. XT-E leds can run up to 1.5a, so you won't be in any trouble there. And you don't want to stress the LDDs.
5. Remove at least a third of the deep reds, and remove the hyper reds entirely IMO. You have waaay to many, as the neutral whites will cover the reds pretty well, and you only need a few for color rendition. The 730nm hyper reds don't do anything for color or growth from what I've read.
6. Remove a few turquoise. Just a few. The number you have right now is a lot.

What you have now seems pretty good though. Although at the very least, remove the hyper red leds.

On optics, 40* will work very well, but 30* is easier to come by.

 

[DoitCheap13]

Agree!

 

[joshlawless]

1. I think it would be safer to just run them in series, especially if you are going with LDD drivers. I can't be sure if your idea won't work, as it sounds pretty plausible. But to err on the side of caution is good.

But if I want to mix emitters with different maximum drive currents on a single driver (and not underdrive one of them), either this, or just wiring a non-emitting resistor in parallel with the lower current emitters, is the only thing I can think of. Although I see you recommend ditching the hyper reds altogether.

2. You want to run only two 72" heatsinks over the tank. I don't think it will look as nice if you run the 4-heatsink setup you have now. You can stick with what you want, but JMO.

I hid it from the render above, but there will be an enclosed cabinet top to hide the light fixtures (and a bunch of other stuff) on top of the tank. This fixture arrangement was designed to maximize the light getting to the ends of the tank (where the very wide/deep overflow is not present), and will allow me to put the right / left / center of the tank on separate dimmer channels (so I can simulate sunrise and sunset, not just with overall intensity, but with directionality (start on the left, end on the right) and color rendering).

3. IMO, ditch the cool whites in favor of some royals and neutrals in a 2:1 ratio of RB:NW. Cool whites won't add anything to your setup.

But do I have enough white overall, right now? Clearing out some of the color channels will buy me a little more heatsink room, but the limiting factor for me is the number of drivers I can fit within the wattage of the 48v power supplies -- I'd prefer one power supply for each 24" heatsink (doable, even if upgrading to the 250w model), and hopefully one for each 36" heatsink (harder if I add another driver or two worth of lights - I'll have to upgrade to a larger power supply that will necessarily include a cooling fan).

4. Run 1000HW drivers on the royals and neutrals and dim them down. XT-E leds can run up to 1.5a, so you won't be in any trouble there. And you don't want to stress the LDDs.

I like this idea, but for safety, would want a hardware dimming solution (so a controller malfunction doesn't burn out any emitters. How does one dim the LDDs? Just an in-line pot, or is there another solution?

5. Remove at least a third of the deep reds, and remove the hyper reds entirely IMO. You have waaay to many, as the neutral whites will cover the reds pretty well, and you only need a few for color rendition. The 730nm hyper reds don't do anything for color or growth from what I've read.

My thinking in including this many of each color was to ensure lighting uniformity/reduce spotlighting (with a lot of emitters driven at a very low power). I've got an alternate layout I'm working on where I pull out a reasonable number of the colored emitters from each channel to make more room for royal blues, but I would like enough to keep a seemless color experience. As far as the hyper reds, I was thinking of using them for sunrise/sunset color emulation, as well as running them (with the 660s) manually for night-time viewing (separate from the lunar emulation I wanted to do with the royal blues at a very, very dim setting).

6. Remove a few turquoise. Just a few. The number you have right now is a lot.

Since the cool blue and turquoise are on the same channel, what do you think would be a good ratio of these colors for helping color rendition in the tank?

What you have now seems pretty good though. Although at the very least, remove the hyper red leds.

On optics, 40* will work very well, but 30* is easier to come by.

Thanks for all your comments! I'll work up a revised layout with more RB, NW instead of CW, and some fewer colors.

 

[asid61]

But if I want to mix emitters with different maximum drive currents on a single driver (and not underdrive one of them), either this, or just wiring a non-emitting resistor in parallel with the lower current emitters, is the only thing I can think of. Although I see you recommend ditching the hyper reds altogether.

I hid it from the render above, but there will be an enclosed cabinet top to hide the light fixtures (and a bunch of other stuff) on top of the tank. This fixture arrangement was designed to maximize the light getting to the ends of the tank (where the very wide/deep overflow is not present), and will allow me to put the right / left / center of the tank on separate dimmer channels (so I can simulate sunrise and sunset, not just with overall intensity, but with directionality (start on the left, end on the right) and color rendering).

But do I have enough white overall, right now? Clearing out some of the color channels will buy me a little more heatsink room, but the limiting factor for me is the number of drivers I can fit within the wattage of the 48v power supplies -- I'd prefer one power supply for each 24" heatsink (doable, even if upgrading to the 250w model), and hopefully one for each 36" heatsink (harder if I add another driver or two worth of lights - I'll have to upgrade to a larger power supply that will necessarily include a cooling fan).

I like this idea, but for safety, would want a hardware dimming solution (so a controller malfunction doesn't burn out any emitters. How does one dim the LDDs? Just an in-line pot, or is there another solution?

My thinking in including this many of each color was to ensure lighting uniformity/reduce spotlighting (with a lot of emitters driven at a very low power). I've got an alternate layout I'm working on where I pull out a reasonable number of the colored emitters from each channel to make more room for royal blues, but I would like enough to keep a seemless color experience. As far as the hyper reds, I was thinking of using them for sunrise/sunset color emulation, as well as running them (with the 660s) manually for night-time viewing (separate from the lunar emulation I wanted to do with the royal blues at a very, very dim setting).

Since the cool blue and turquoise are on the same channel, what do you think would be a good ratio of these colors for helping color rendition in the tank?


Thanks for all your comments! I'll work up a revised layout with more RB, NW instead of CW, and some fewer colors.

1. All you have to do to keep multiple colors on the same channel is to have the LDD drivers controlling both colors controlled by the same dimming signal.

2. Okay, then it will look good anyway. That's a really sweet idea!

3. I'm not saying remove the cool whites entirely. I mean, replace them with neutral whites and royal blues. You should not need to add any more power supplies, as the total draw will be the same.

4.DO NOT DIM THE LDD DRIVERS WITH AN INLINE POT. You'll waste a ton of electricity, and it won't work; the LDDs will just supply more current until they burn out trying.
Do you see the dimming wire? It's right next to the V+ wire to power supply. You apply a PWM dimming signal to the PWM pin to dim the LDDs. You can't use an analog voltage like normal.
Many Arduino-based controllers offer PWM dimming. How many channels do you want?

5. Okay. But, all you would need to do in order to unsure an even spread would be to spread out the reds more. Plus, you would be able to add more hyper violets.
The hyper reds won't add anything to the night viewing experience. Deep reds are enough. Also, don't worry about the violets being overpowering. They are extremely dim to the human eye.

6. The cool blues and turquoise should be mixed in a 2:1 ratio of CB:T IMO. The cool blues help a lot with growth, whereas the turquoise are only for color rendition and should take a secondary spot.

The color ration should be 4:2:2:1:1:1 Royals:Neutrals:Violets:Red:Blue:Turquoise, with the Reds and turquoise being run at half the power of the blues, which should be run pretty high (700+ma).

 

[zachts]

To clarify - I think that running parallel pairs in series like this will limit the damage that burnt out star can do, because if one star in a pair burns out (breaks that sub-circuit), then all of the current coming from the driver will pass through the remaining star in the pair, quickly burning it out, too, like a fuse, protecting the rest of the stars connected to the same driver. Not that they even need protection - they're still going to be running in parallel, given that the line ties together between every pair (so only the star next to the burned out star will ever see a 1000mA drive current).

This strikes me as better than running entire strings of LEDs in parallel, where one whole string can burn out if a single star on a parallel string burns out.

Anyone who can tell me if my understanding isn't correct will be very much appreciated!

That would possibly work however your likelely to end up with one LED getting 750mA and one getting 250mA as the two colors will not have the same Forward Voltage. your better off running two proper parrelel strings and balance the same number of each color on each string. then follow proper parrellel build etiquet and ballance the two strings if needed. this will ensure no problems.

Also just use Luxeon Rebel ES LEDs or CREE for the Cyan and True Blue colors, they can handle 1000mA so there'd be no problem with over current if one failed. (available from Steve's LED or RapidLED) Side note: Steves has 1000mA 420nm violets.........

1. I think it would be safer to just run them in series, especially if you are going with LDD drivers. I can't be sure if your idea won't work, as it sounds pretty plausible. But to err on the side of caution is good.

+1 on series LDDs are cheap why not, and then you could controll them as separate channels potentially.

4. Run 1000HW drivers on the royals and neutrals and dim them down. XT-E leds can run up to 1.5a, so you won't be in any trouble there. And you don't want to stress the LDDs.

How would running the 700mA drivers stress them? the drivers deliver the current specified in thier name, no more no less, within the voltage range they can opperate over. it will not harm anything and running the leds at lower currents will make them more efficient and produce less heat relative to light output. LDDs are excellent drivers and can safely operate a single led even off of a 48v power supply!

5. Remove at least a third of the deep reds, and remove the hyper reds entirely IMO. You have waaay to many, as the neutral whites will cover the reds pretty well, and you only need a few for color rendition. The 730nm hyper reds don't do anything for color or growth from what I've read.

Agree, I would even consider ditching all of these reds as all they would do is grow algae over a reef tank. people think these colors are good for coral just because fluorescent and MH produce them as a side effect of producing visible light or as a hold over from originally being developed for terrestrial plants.

I personally like the looks of 617-630nm Reds used for supplementing aesthetics and color rendering. these are the wavelengths that are more visible to the human eye. I aggree you have way more than you need but like your approach of having lots since it will greatly reduce the possibility of color banding in the tank! you would probably be safe running LDD 300s on the reds and have more than enough for you needs.

On optics, 40* will work very well, but 30* is easier to come by.

IMHO, I would not use any optics at first only, add them if you find you have dimmed up to 100% and need more light for coral growth. I would also probably suggest 60 or 80 degree for better spread and blending as 40 and 30 degree really create some hot spots unless the lights are many feet above the tank.

But if I want to mix emitters with different maximum drive currents on a single driver (and not underdrive one of them), either this, or just wiring a non-emitting resistor in parallel with the lower current emitters, is the only thing I can think of.

don't do this, the resistor will just waste power and do all sorts of not nice things. there is nothing wrong with underdriving an LED, it makes them more efficient and is how they are INTENDED to run by the manufacture. CREE rarely produces a fixture with drive current over 700mA even though the LEDs can run at 1500mA, and 350mA drive currents are typical in a great many commercial light fixtures.

But do I have enough white overall, right now? Clearing out some of the color channels will buy me a little more heatsink room, but the limiting factor for me is the number of drivers I can fit within the wattage of the 48v power supplies -- I'd prefer one power supply for each 24" heatsink (doable, even if upgrading to the 250w model), and hopefully one for each 36" heatsink (harder if I add another driver or two worth of lights - I'll have to upgrade to a larger power supply that will necessarily include a cooling fan).

keep in mind that LDD drivers do not draw power the way many others do. calculate you PSU needs based on actuall wattage of you array. for example a LDD-1000 will not be drawing a full 1 amp from a 48volt PSU if it has less than 46v of LED running on it. (6 leds running at 3.5v for example would only be drawing ~21 watts not the 48 watts you might expect.

I like this idea, but for safety, would want a hardware dimming solution (so a controller malfunction doesn't burn out any emitters. How does one dim the LDDs? Just an in-line pot, or is there another solution?

LDDs dim using PWM so they are compatible with any Arduino type controller such as the typhoon, or the PWM Reef Angle. they can be run off of other 0-10v controllers like Apex using some sort of simple converter board as well.

My thinking in including this many of each color was to ensure lighting uniformity/reduce spotlighting (with a lot of emitters driven at a very low power). I've got an alternate layout I'm working on where I pull out a reasonable number of the colored emitters from each channel to make more room for royal blues, but I would like enough to keep a seemless color experience. As far as the hyper reds, I was thinking of using them for sunrise/sunset color emulation, as well as running them (with the 660s) manually for night-time viewing (separate from the lunar emulation I wanted to do with the royal blues at a very, very dim setting).

An excellent approach IMO. it will increase LED efficiency and reduce heat generated! as well as give better color blending and uniformity.

 

[joshlawless]

That would possibly work however your likelely to end up with one LED getting 750mA and one getting 250mA as the two colors will not have the same Forward Voltage.

Excellent point. Ignoring the illustration I put in of Turquoise and Cool Blue, for the moment, my proposed approach should at least work if the parallel pairs are the same color (e.g., two 730nm emitters in parallel, then one 660 by itself, then two 730s in parallel again), yes? For the blue/turquoise, your objection would be moot if I ran parallel pairs of the same color, instead of what is illustrated.

keep in mind that LDD drivers do not draw power the way many others do. calculate you PSU needs based on actuall wattage of you array. for example a LDD-1000 will not be drawing a full 1 amp from a 48volt PSU if it has less than 46v of LED running on it. (6 leds running at 3.5v for example would only be drawing ~21 watts not the 48 watts you might expect.

This. Is. Awesome.

I didn't know this. I assumed that if you ran even a single LED on a LDD without dimming, that you'd be drawing 700mA. (Now that you tell me otherwise, I'm forehead-slapping. Of course on LED won't pull 700mA by itself).

This was a significant design consideration for me - the reason I was trying to use only ~5 700mA LDDs on the 180W power supply. That changes everything -- I'm happy to pay a few bucks more for each LDD so that I can have far more control over the mixture of colors and number of channels handled by each power supply. I just _really_ want to keep it to one power supply per fixture.

 

[zachts]

Excellent point. Ignoring the illustration I put in of Turquoise and Cool Blue, for the moment, my proposed approach should at least work if the parallel pairs are the same color (e.g., two 730nm emitters in parallel, then one 660 by itself, then two 730s in parallel again), yes? For the blue/turquoise, your objection would be moot if I ran parallel pairs of the same color, instead of what is illustrated.

yes your red idea will work OK. you may find a few of the 730 pairs are not evenly illuminated though, but this can be corrected by measuring the pairs voltage in operation and pairing them up. simple to do on the table top before mounting to heatsinks especially since your using LDDs you can just us one of them to test LEDs to make up you strings. you wouldn't need to worry about over current on the reds since it would be set according to the 660nm led and the two 730nm leds would just theoreticaly get half the current each (+/-50 or so mA if they are closely balanced)

search and read up on parrellel LEd builds particularly JP's thread and posts by kcress. but basically you want the same number of each color on each of the two parreleled strings and they you measure each strings operating voltage and current and see if any further "balancing" is needed.

This. Is. Awesome.

I didn't know this. I assumed that if you ran even a single LED on a LDD without dimming, that you'd be drawing 700mA. (Now that you tell me otherwise, I'm forehead-slapping. Of course on LED won't pull 700mA by itself).

This was a significant design consideration for me - the reason I was trying to use only ~5 700mA LDDs on the 180W power supply. That changes everything -- I'm happy to pay a few bucks more for each LDD so that I can have far more control over the mixture of colors and number of channels handled by each power supply. I just _really_ want to keep it to one power supply per fixture.

you shouldn't have two much trouble using one PSU per fixture, 180watts of CREE and Luxeon emmiters is a tremendous amount of light! on par with a 250-400watt metal halide depending on you led color selections and ratio of blue to white.

And actually one led WILL draw 700mA of current from the driver. the driver however will not be drawing 700mA of current from its PSU. the exact draw of the driver would be difficult to determine ahead of time but using watts of LEDs on the output side gets you close, just leave 20% or so headroom on the PSU for good measure. Meanwell publishes data sheets with power curves that help to illustrate how they work.

 

[joshlawless]

And actually one led WILL draw 700mA of current from the driver. the driver however will not be drawing 700mA of current from its PSU. the exact draw of the driver would be difficult to determine ahead of time but using watts of LEDs on the output side gets you close, just leave 20% or so headroom on the PSU for good measure. Meanwell publishes data sheets with power curves that help to illustrate how they work.

That makes sense. One LED with a forward voltage of 3V drawing 700mA would be about 2.1W, plus the 3V of voltage drop through the LDD would be about 4.2W, which coming from a 48V PSU would be around 87.5mA.

Or so. :fun5:

 

[joshlawless]

Okay, so with the MakersLED heatsink, the most efficient pattern I can visualize for even light distribution is based on an evenly-spaced hexagonal grid of emitters. There are five possible row positions for each emitter, so here's a repeating pattern I've come up with:

The blue/white stripes represent a 3-UP star with 2 royal blue XT-E emitters and one neutral white emitter. The white hexes are neutral white (same as the 3-up). The red, purple, blue and turquoise colors are probably self-explanatory.

The ratio here is 10 RB : 7 NW : 3 Cool blue : 2 Turquoise : 2 UV : 1 Red

The final column will be the same as the first, pushing the RB ratio just a tad higher (depending on the length of the fixture). Here's an example of what I mean:

The drawback to this pattern is that the white emitters aren't quite as evenly distributed as I'd like (the 3-UPs are next to plain white emitters, lending that pattern a little less even density than ideal).

Now that I know I can run more than 5 LDDs off a single PSU, so long as the string isn't fully populated, I feel a lot more design freedom. Thanks zachts!

 

[asid61]

On each segment of the pattern, replace a white with a hyper violet. You want a lot of hyper violets in the 430nm range.

 

[joshlawless]

On each segment of the pattern, replace a white with a hyper violet. You want a lot of hyper violets in the 430nm range.

Done, and added back in one red in lieu of the other white. Couldn't bear to have so few.

 

[joshlawless]

With this pattern (smooshed a little bit laterally) I can fit 7 full repetitions of these 15 stars and an extra column of three 3UPs on a 36" fixture, which gives me

38x neutral white
76x royal blue
21x UV
21x cool blue
14x turquoise
14x red

On each 24" heatsink, I can fit just shy of five iterations of this pattern (dropping the last two columns, or two cool blue, and one each of uv, red and turquoise, from the last iteration), such that each 24" fixture contains:

25x neutral white
50x royal blue
14x UV
13x cool blue
9x turquoise
9x red


With all four fixtures included, that would provide, over the whole 72x33x40 tank:

126 neutral white
252 royal blue
70 UV
68 cool blue
46 turquoise
46 red

Seems likely to be enough light, even if I optic down the 3-UPS with tight 40 degree lenses to punch down the full 40" depth.

Follow-up question, should the cool blues be tied in with the royal blues, with the turquoise, or even on their own channel? With all these extra LDDs I'll be wiring in, may as well separate them out for more color control (via Reef Angel, and lots of dimming expansions).

 

[zachts]

That makes sense. One LED with a forward voltage of 3V drawing 700mA would be about 2.1W, plus the 3V of voltage drop through the LDD would be about 4.2W, which coming from a 48V PSU would be around 87.5mA.

Or so. :fun5:

something like that, although the LDD is less efficient with only 1 led something like 75-80% so you have to figure for that as well.......... upwards of 95% efficient with a full load

 

[zachts]

Seems likely to be enough light, even if I optic down the 3-UPS with tight 40 degree lenses to punch down the full 40" depth.

Follow-up question, should the cool blues be tied in with the royal blues, with the turquoise, or even on their own channel? With all these extra LDDs I'll be wiring in, may as well separate them out for more color control (via Reef Angel, and lots of dimming expansions).

You sir will have more than enough light, probably even without any optics!!!! So I'd maintain that you should only add them if you find you have trouble growing SPS near the bottom of the tank.

I'd put the Cool Blues on thier own Channel, even if it's not controlled separateley you could at some point do so.