DIY LEDs - The write-up

[Reef_Matrix29]

I currently do not use any "sealant" over my LED's, but rather have the array suspended 6 - 8 inches off the water level and circulation to help reduce salt spray; I'm sure that over time some will deposit, but no plans for prevention just yet.

You are planning 4 x 100W T5's and 60 LED's? I have a hybrid system now too, but you seem like your tank is T5 dominated and the LED's are the accent light. I would suggest more LED's and perhaps not overdriving your bulbs unless your corals aren't taking to the light put out by the configuration.

I'm still a little confused about how your canopy will look and the need for 6 heatsinks, maybe a hand drawn picture would help us visualize it better. When I upgrade to a 120G, I'm planning on just 2 heatsinks @ 24 x 12.5.....if I can get 24 x 18 would be even better, but still no more than two for me. In my experience you don't get spotlighting with no optics, so you can space them how you wish, but you will have uneven coverage. Spot-lighting is with optic usage and if you have an area that needs deeper penetration, you could pre-design for certain sections of your array to have optics on them and pack non-optic LED's around it to "light" the shade caused by the focused beam. (hope that made sense)

 

[Zythum]

Hi,

I would go T5 or LED, noth both. The position of the heatsinks is the word "heat". The hinge in the middle is for opening from the front or the back.

The stars are the remaining wood from the top of the canopy

canopy top view:

----------------------------------------
|***************************** |
|****heat*****heat*******heat****|
|***************************** |
---------------------------------------- <-- hinge in the middle
|***************************** |
|****heat*****heat*******heat****|
|***************************** |
----------------------------------------

 

[Reef_Matrix29]

Okay, this kind of resembles the new aquaillumination setup in which there are 6 banks (clusters) of LED's per module. My thoughts are as follows: once you see the size and weight of the heatsinks, I don't think you are going to want to suspend 6 of them in your canopy, let alone suspend 3 of them from a "flip top" hood. I would encourage you again to get a 2 medium to large heatsinks, pack the LED's on there with good optics on the edges to prevent light spillage and perhaps some T5's for the dark spots or under lite edges of the tank. Ultimately you will make the best array per your vision, but I would strongly urge you to reconsider that much metal over your expensive investment. I think cramming more LED's and adding some supplemental T5's would do the trick, just my opinion.

Whatever you do, please provide pics for us to follow along with you.

 

[bsk997]

Nice write up.
I'm looking at adding some LEDs with the meanwell 0-10v option so I can dim them with either an Apex or Profilux in the future.
My main purpose of the LEDs is to hopefully provide some some shimmer to my 8x54w T5 setup and to provide sunrise/sunset option.

Do you guys thinking adding a row of say 12 or 24 LEDs spaced in a straight 4' strip would be powerful enough to add shimmer? I've always heard people say that LEDs dont provide enough power to provide the shimmer but most the time they're talking about regular led moonlight strips vs high powered cree LEDs.
I'm afraid that the LEDs would be drowned out by the power of the T5's.
Thanks for the suggestions.

 

[grouper therapy]

Sorry wrong forum

 

[krzysieks]

Should I use 23 or 36 degree optitics for my led light? I will have 60 LED (140 degree without optics) for 75 gallon tank. 48L x 18W x 20H. I have sps in the back of the tank about 5" from the top, zoas, mushrooms, lps in middle and bottom. Thanks

 

[Reef_Matrix29]

Nice write up.
I'm looking at adding some LEDs with the meanwell 0-10v option so I can dim them with either an Apex or Profilux in the future.
My main purpose of the LEDs is to hopefully provide some some shimmer to my 8x54w T5 setup and to provide sunrise/sunset option.

Do you guys thinking adding a row of say 12 or 24 LEDs spaced in a straight 4' strip would be powerful enough to add shimmer? I've always heard people say that LEDs dont provide enough power to provide the shimmer but most the time they're talking about regular led moonlight strips vs high powered cree LEDs.
I'm afraid that the LEDs would be drowned out by the power of the T5's.
Thanks for the suggestions.

I can tell you firsthand that 12 - 24 LED's WILL add the shimmer that you look for, however, the amount that you see will depend on the current you drive them at and whether you use optics or not.

 

[Reef_Matrix29]

Should I use 23 or 36 degree optitics for my led light? I will have 60 LED (140 degree without optics) for 75 gallon tank. 48L x 18W x 20H. I have sps in the back of the tank about 5" from the top, zoas, mushrooms, lps in middle and bottom. Thanks

Personally, you don't really NEED optics to keep these SPS happy at the top of the tank, but if you do add them you will have some serious spotlighting. Your tank is the same depth as mines and I go without optics and my SPS are oriented towards the top as well. If you had a 24" - 30" deep tank, I would suggest optics for certain, but our tanks are shallow enough it seems and 60 LED's seems like a fair spread of light and penetration thus far from people that have built LED array's. Regardless, if you find that your SPS aren't responding well to the light ouput, you can always drive them to 1000mA and/or add optics if you like.
:dance:

 

[Doahh]

Ugh... Ordered and 6 of the 8 Royal Blue LEDs I received are defective...
On another note can anyone tell me which pot is which on the dimmable meanwell drivers?

 

[krzysieks]

Personally, you don't really NEED optics to keep these SPS happy at the top of the tank, but if you do add them you will have some serious spotlighting. Your tank is the same depth as mines and I go without optics and my SPS are oriented towards the top as well. If you had a 24" - 30" deep tank, I would suggest optics for certain, but our tanks are shallow enough it seems and 60 LED's seems like a fair spread of light and penetration thus far from people that have built LED array's. Regardless, if you find that your SPS aren't responding well to the light ouput, you can always drive them to 1000mA and/or add optics if you like.
:dance:

All LEDs I will drive 1000mA, LUXEON Rebel LEDs have 140 degree beam with out optics. Isn't it too wide without optics? Waste of light?

 

[der_wille_zur_macht]

LUXEON Rebel LEDs have 140 degree beam with out optics. Isn't it too wide without optics? Waste of light?

Depends on what you mean by "too wide" and "waste of light" really. It's probably roughly comparable to the spread you'd get from a typical reef lighting fixture (i.e. metal halide lamps or florescent lamps). So, you'll be wasting a bit of light, and getting some on your glass, which will encourage algae growth, but again - it really won't be much worse than other types of reef lighting. And, the 140 degree number is total angle - the light is concentrated pretty strongly near the middle of the field anyways. Most HB LED datasheets have plots showing intensity, and you can see that it drops off pretty sharply around 90 or 100 degrees or so in most cases, even if the total angle is bigger.

So, from a certain point of view, even the best reflectors for most reef lighting technology are pretty crappy, so LEDs without optics isn't really terrible.

However, within the realm of LED lighting, you have the opportunity to do way better (in terms of using the light rather than wasting it), if you want to. Optics concentrate the light into a smaller area. For many people, this means you get to use more of it.

But, for some designs, this concentration of the light isn't a big advantage. For instance, in a shallower tank, you don't really want to concentrate the light, unless you are packing a TON of LEDs above the tank and hence won't get the spotlighting effect. On a shallow tank, with the LEDs close to the water line and without optics, you are using a fair amount of the light anyways, since even the light that leaves the LED at a greater angle (i.e. more sideways) will likely be utilized before it has a chance to escape.

Plus, even if you do have a deeper tank, and you use tight optics and tight spacing, you may be able to utilize the light more efficiently, but that's not the whole story. Besides concentrating the light into a narrower beam, optics make the light far more directional (i.e. the light is more laminar, like a laser, rather than random and spread out, like an incandescent bulb). Again, this can be a good thing, or a bad thing, depending on your requirements. If you were to use super tight spacing and super narrow optics, with all your LEDs on the same plane (i.e. mounted flat on a heatsink), you'd get really weird growth from your corals, since all the light would be directly straight down. Lower branches and colonies would be totally shaded, and probably die off.

So, when designing with optics, you need to consider directionality of the light, in addition to tightness of the beam. Hence, if you were designing a high intensity fixture for SPS using tight spacing and tight optics, you would probably be best off to mix in some LEDs without optics, to get some "random" more horizontal light, rather than only the straight-down light from the optics. Or, position banks of LEDs on different planes above the tank, so that some of the light enters from an angle, and some straight down.

 

[kcress]

Nice discussion der_wille_zur_macht!

 

[Reef_Matrix29]

I agree, great breakdown!

Adding just one more thing to it...since this is a matter of preference and not fact, driving all LED's at 1000 mA may shorten the life of your array as a whole. I believe that most people are pushing them @ around 700 mA max to get that 11+ years life, but who can really say at this point. Another suggestion to consider re-capturing some of that light would be reflectors. My T5 reflectors are positioned at the front and rear of my canopy, once I added them the light has drastically cut down from spilling our of my tank. Well, the sides are still an issue, but the front and back are fine now.

Just an idea since you mentioned a "waste of light"...

 

[der_wille_zur_macht]

I believe that most people are pushing them @ around 700 mA max to get that 11+ years life, but who can really say at this point..

This is another interesting point for debate. The figures most people refer are probably related to this statement in the datasheet for XR-E LEDs:

Cree projects royal blue, blue, green and white XLamp XR-E LEDs to maintain a mean 70% lumen maintenance after
50,000 hours, provided the LED junction temperature is maintained at or below 90°C and ambient air temperature is
maintained at or below 85°C.

I know someone in one of these threads stated 50k hours at 700mA, but I don't see that exactly in the datasheet - just this bit about 50k hours at a certain junction temp and ambient temp.

I don't know if anyone is measuring junction temperature in our DIY experiments. And, this is for a 70% lumen maintenance - it doesn't really tell you anything about failure rate. The LEDs could only average a year of life, or 100 years, regardless of how many lumens the manufacturer expects them to have after 50,000 hours. Though, It's probably fair to assume that the 50k hours number is a good approximation of expected lifetime.

It's also interesting to look at the datasheet graphs for output vs. temperature and output vs current for each color, when considering lifetime, efficiency, and choice of operating current.

 

[der_wille_zur_macht]

A further thought, IMHO the biggest difference between LEDs and other forms of lighting is the fine resolution of control we have with LEDs. Not just intensity and color, but exact point of origin and direction of the light.

I think this is going to be the hardest thing for us hobbyists to wrap our heads around, since we're not used to so much granularity. People who like T5's brag about how they can swap out one of the 8 lamps on their fixture and get a whole different look to the tank. While that is true, an LED-lit tank might have 150 point sources of light, each essentially variable for intensity, color, location, and angle. It's several more degrees of freedom. Want the light on one particular SPS to be a hair bluer than the rest of the tank? No problem! Or, a hair more intense, or hitting it from a different angle, etc etc etc.

 

[Reef_Matrix29]

+1

This (LED lighting) will open up options for hobbyist that have yet to be experienced with pin-point control of lighting within their reef. Sure, it will take A LOT more planning before construction, but we never said that new innovations would be easy or cookie cutter!

I'm already planning my next array now and this one has only been built a month, yet I'm perfectly happy with the outcome!

 

[Zythum]

Hi,

I am planning mine now, it's just hard to design a canopy that can be converted from 2 VHO to LEDs, but I am getting there . I have to solve the problem of lifting the canopy too, I think I will use a pulley system with a boat trailer crank. Here is what I tough of so far:

- I have all the hardware to make 2x 70VDC 3.5A power supplies, I guess one for the white leds and one for the blue ones. That means I can power 8x 16-17 LEDs series with 700mA.

- To drive the LEDs, I found the LM3404HV, a nice LED driver that can take up to 72VDC, but is not available in DIP format. It has a PWM input for dimming. I would need 6x of these to drive 102 leds (6x17) over my 120G (60x18x26H). The development board from National Instruments costs 50$ each, but are not customized for my voltage. The best option I see so far, to do 2 PCB with 3-4 drivers each, at PCB express, for 96$.

- My PLC doesn't have analog output module installed ($$), and an Omron CQM1 also needs a power supply for the analog modules. I have a supply, but I use it for my analog inputs module. I also have a 16 transistor output module that I can use. I just have to put a PIC on a breadboard that I have laying around, and set it up with PWM outputs. If I make registers, I could drive separately the different banks.

- For the fans, a PIC on a breadboard with some temperature sensors would also make wonders.

When I start building this, I will make a post to present my PLC setup with the 120G running. I have to make a test unit to light the sump before I spend so much money on more electronic parts . The price of the LEDs may even come down eventually, or more efficient and/or powerful ones may come out. I also wanna see what other people do to get different ideas.

 

[WangoTANGo]

Wow, awesome thread.

I've been tossing around the idea of a 60x24x20 for a while. I think doing all LED would be a bit pricey, so was wondering if something like this would work:

-----=60" T5ho
o = LED w/ 60deg optic (total of 76; 2x19 and two 1x19)

-------------
o o o o o o o o
--------------
o o o o o o o o
o o o o o o o
--------------
o o o o o o o o
-------------

-Justin

 

[GeeTen]

Do you think 2 of these will be fine for a 60G FOWLR?

Cree 6xQ6 + 6xRB @ 1000mA

Will the fans be necessary or I could go without?

 

[der_wille_zur_macht]

Hi,

I am planning mine now, it's just hard to design a canopy that can be converted from 2 VHO to LEDs, but I am getting there . I have to solve the problem of lifting the canopy too, I think I will use a pulley system with a boat trailer crank. Here is what I tough of so far:

- I have all the hardware to make 2x 70VDC 3.5A power supplies, I guess one for the white leds and one for the blue ones. That means I can power 8x 16-17 LEDs series with 700mA.

- To drive the LEDs, I found the LM3404HV, a nice LED driver that can take up to 72VDC, but is not available in DIP format. It has a PWM input for dimming. I would need 6x of these to drive 102 leds (6x17) over my 120G (60x18x26H). The development board from National Instruments costs 50$ each, but are not customized for my voltage. The best option I see so far, to do 2 PCB with 3-4 drivers each, at PCB express, for 96$.

This will be an interesting approach. Make sure you are under the max thermal load on that driver chip. Often, if a chip is rated through 72v and 1A (for example), it'll hit thermal overload before both are maxed out (i.e. at 72v and only 500mA, for example). Does the LM3404HV use an external switch? That would give you more flexibility in terms of being able to actually max it out without overloading the IC.

I'd be interested to know where/how you're getting 70v 3.5A supplies cheaply enough to make it worthwhile, compared to the $15 24v 6 - 8A supplies most people are using!

- My PLC doesn't have analog output module installed ($$), and an Omron CQM1 also needs a power supply for the analog modules. I have a supply, but I use it for my analog inputs module. I also have a 16 transistor output module that I can use. I just have to put a PIC on a breadboard that I have laying around, and set it up with PWM outputs. If I make registers, I could drive separately the different banks.

- For the fans, a PIC on a breadboard with some temperature sensors would also make wonders.

When I start building this, I will make a post to present my PLC setup with the 120G running. I have to make a test unit to light the sump before I spend so much money on more electronic parts . The price of the LEDs may even come down eventually, or more efficient and/or powerful ones may come out. I also wanna see what other people do to get different ideas.

Looking forward to hearing about your build. Sounds like we are on similar paths.