sfsuphysics
Supporting Member
Well let me first by saying, I was one who was hesitant to using LEDs, but in my defense the really super bright ones that are out now via Cree didn't exist at the time 
The reasoning for wanting to do this is I wanted to produce "hot spots" of light on my tank, even though my corals have grown to occupy a rather large area my "dream tank" (doesn't everyone get to this point??) will be much more spaced out, although in my defense (again) my tank was spaced out when I originally set it up, the damn corals just ruined my plan!
Currently my lighting setup is 2 x 250w halides + 6 T5s, there's front to back symmetry either, I have 1 actinic bulb, the halides, then the 5 other T5s, 4 of which are blue plus. The reasoning is my light heavy sps would occupy the front, the lower light corals (LPS) would be in the back... well as you can maybe figure there wasn't a whole lot of additional thought that went into it, very quickly however I realized my LPS would be mostly unseen. So I had the idea of moving stuff around, however since all the SPS grew into that "rockwall" look (even though things were on separate pillars separated by at least a foot) I didn't want a back rockwall either... so I decided to move half of the SPS back... regardless of how I did it the problem is now the stuff in the back doesn't have very powerful lighting, and due to the long linear nature of the T5s its not like I could simply move the halide back as the T5s are in the way. I do have some other halides, but I really didn't want to go that direction... hence the LEDs.
I liked the idea of the PAR38 LEDs, however something about them made it a bit of a hard sell (probably the $120 price tag for 5 LEDs, regardless of how cool it looked). So like always, I decided I'd do it myself, if anything just to see if it can be done!
Ok long winded preamble over.. onto the build!
There are four major components of any LED build, first the LEDs themselves, the lenses which allow you to direct light, the power source, and the thermal management system. I'll address each of these in turn.
LEDs
Well like most reef people, we tend to want colors that "pop" and sometimes growth (although I've gotten to the Jake Adams' mindset of my corals don't need to grow that fast anymore). So that meant Cree LEDs, Royal Blue & Whites. I kept my eye on a website called rapidled.com (which is over in Oakland btw.. so you'll be shopping locally and literally get your stuff in 2-3 days), and noticed they have fairly good prices on everything that you might like. I finally decided to pull the trigger when I saw them have the Cree XP-G white LEDs, which long story short, gives 30% more light output at the same power level as the XR-E white LEDs. The downside ... they're sized differently than the XR-E (I'll explain why this is important in the next section). So I made an order, got a bunch of the XP-G cool whites, a bunch of the XR-E royal blues (no XP-G royal blues yet) and got them in 2 days. BAM! Did some testing with them, used a transformer in conjunction with a decade box (basically a big ass POT) just to keep the voltage under control, when I hooked 3 whites to my proper power source it fried them... I'm still trying to figure out why, the transformer states +48V but the website says I can use 3-12 LEDs... or it could be the XP-G use less voltage than the XR-E and as a result I fried them with too much voltage (if I only put 4 LEDs together...) anyways that was about a $25 mistake!
Lenses
I decided to get 1 of each type of lens. 40° 60° & 80° just to see which spread I liked... however the realization of my blunder hit me... the light from the un-lensed leds would really ruin any chance of seeing which I liked... so I'm going to stick with math to figure out which lens I want
Ok the bad part.. these lenses only fit the XR-E LEDs, the XP-Gs are way too small, there are some 3rd party lenses out there that supposedly fit. The other downside is the viewing angle for the XP-Gs (whites) is 120° which is a little broad for a the focus beam that I really want. However for now I'll just wait to see what comes out, I'm in no hurry to throw this over the tank.
Power source
I went with a Meanwell driver, 700mA constant current, no dimming, etc etc. I just wanted a stand alone driver with no worries of dimming. Maybe in the future dimming can be added but for now, I don't dim any of my lights, so why should I care about dimming the LEDs (besides I don't think my AC3 has the capability to dim them).
thermal management
Here's where the picture parts of the build will come into play. I thought about a heatsink from one of those online stores, however I really wanted instant gratification, doubly so since I was in home depot! So I got my weapon of choice. aluminum C-channel, 1/16" thick, 8 feet long (my lights are not going to be that long!) cost about $7 or so.
I forget how wide it is, but it's just wide enough to hold one of the LEDs which is what I wanted.
Not sure if this is going to enough surface area/mass to pull heat away, but more on this later
Drilled some holes for the screws to hold each star onto it.
Lesson Learned: Get a drill press! So much easier to do, while the drill didn't ride on the surface when I finally punched through the whole drill went too and I dinked the aluminum quite a bit.
More holes.... what are these for?
Remember I did not want any strip lights (t5s) this allows me to go modular with my LEDs, so I could change them how I see fit. Different color strips, or even if there's not enough thermal management I could put empty ones in between to add to the overall mass/surface area of the sink. I did however plan to actively cool it with a fan if needed, which is why I made this 4 wide. (I could go more, but I wanted to cool this not the surface of my water.
Finally put all the SOBs on there. Everything wired, only the 3 on each bar are wired together, each bar has its own wires so that if I decide to change bars I can do so without needing to unsolder wires from the LED.
Lesson's Learned: Go with machined screws instead of sheet metal screws, while these hold into the aluminum my palm has a blister on it from having to push down and turn to get these in. The need to put nuts on each machine screw might be worth the extra effort, plus the holes don't have to be as exactly sized. The other thing I didn't realize is these are galvenized/zinc screws, they will rust, I might have to change them out for stainless, although my plan is to have an acrylic shield over the whole thing anyways.
BAMMO! Let their be light! Ok in reality you can't tell how bright this is, because the CCD got oversatured a bit. However the fact I walked around with 12 dots in my vision for a few minutes afterwards tells me it's nice and bright
There are still a few things that need to be done, after a few minutes the aluminum is warm to the touch (not hot mind you), but who knows what it'll feel like after a few hours. I need to get one of those IR thermometers to do some further testing, both on the aluminum (to see if I do in fact need the fan) but also on the LEDs themselves as I want to make sure there's good thermal contact between them and the aluminum.
The aforementioned acrylic shield also needs to be built.. in fact an entire housing I'm guessing, as I need to figure out a way to hang the fixture too. My plan is to drill holes in the shield just enough to to fit the lenses through, perhaps with a rubber gasket simply so there's no additional loss of light.. but we'll see!
Also need to clean up some of the solder joints, its hard to see these things as it is plus when you're temporarily blinded by the brightness noticing the solder joints is a tad difficult
However with that said, I have a rather large summer time "Honey Do" list, so the end result it might be a while before I get this over the tank Overall though, this is probably twice as bright as the PAR38 fixtures, at around the same price (when all is said and done), so you're not going to save a ton of money, however if I only needed one or two of those PAR38 bulbs it would have been a no brainer to simply buy them.
The reasoning for wanting to do this is I wanted to produce "hot spots" of light on my tank, even though my corals have grown to occupy a rather large area my "dream tank" (doesn't everyone get to this point??
) will be much more spaced out, although in my defense (again) my tank was spaced out when I originally set it up, the damn corals just ruined my plan!Currently my lighting setup is 2 x 250w halides + 6 T5s, there's front to back symmetry either, I have 1 actinic bulb, the halides, then the 5 other T5s, 4 of which are blue plus. The reasoning is my light heavy sps would occupy the front, the lower light corals (LPS) would be in the back... well as you can maybe figure there wasn't a whole lot of additional thought that went into it, very quickly however I realized my LPS would be mostly unseen. So I had the idea of moving stuff around, however since all the SPS grew into that "rockwall" look (even though things were on separate pillars separated by at least a foot) I didn't want a back rockwall either... so I decided to move half of the SPS back... regardless of how I did it the problem is now the stuff in the back doesn't have very powerful lighting, and due to the long linear nature of the T5s its not like I could simply move the halide back as the T5s are in the way. I do have some other halides, but I really didn't want to go that direction... hence the LEDs.
I liked the idea of the PAR38 LEDs, however something about them made it a bit of a hard sell (probably the $120 price tag for 5 LEDs, regardless of how cool it looked). So like always, I decided I'd do it myself, if anything just to see if it can be done!
Ok long winded preamble over.. onto the build!
There are four major components of any LED build, first the LEDs themselves, the lenses which allow you to direct light, the power source, and the thermal management system. I'll address each of these in turn.
LEDs
Well like most reef people, we tend to want colors that "pop" and sometimes growth (although I've gotten to the Jake Adams' mindset of my corals don't need to grow that fast anymore). So that meant Cree LEDs, Royal Blue & Whites. I kept my eye on a website called rapidled.com (which is over in Oakland btw.. so you'll be shopping locally and literally get your stuff in 2-3 days), and noticed they have fairly good prices on everything that you might like. I finally decided to pull the trigger when I saw them have the Cree XP-G white LEDs, which long story short, gives 30% more light output at the same power level as the XR-E white LEDs. The downside ... they're sized differently than the XR-E (I'll explain why this is important in the next section). So I made an order, got a bunch of the XP-G cool whites, a bunch of the XR-E royal blues (no XP-G royal blues yet
) and got them in 2 days. BAM! Did some testing with them, used a transformer in conjunction with a decade box (basically a big ass POT) just to keep the voltage under control, when I hooked 3 whites to my proper power source it fried them... I'm still trying to figure out why, the transformer states +48V but the website says I can use 3-12 LEDs... or it could be the XP-G use less voltage than the XR-E and as a result I fried them with too much voltage (if I only put 4 LEDs together...) anyways that was about a $25 mistake! Lenses
I decided to get 1 of each type of lens. 40° 60° & 80° just to see which spread I liked... however the realization of my blunder hit me... the light from the un-lensed leds would really ruin any chance of seeing which I liked... so I'm going to stick with math to figure out which lens I want
Ok the bad part.. these lenses only fit the XR-E LEDs, the XP-Gs are way too small, there are some 3rd party lenses out there that supposedly fit. The other downside is the viewing angle for the XP-Gs (whites) is 120° which is a little broad for a the focus beam that I really want. However for now I'll just wait to see what comes out, I'm in no hurry to throw this over the tank.
Power source
I went with a Meanwell driver, 700mA constant current, no dimming, etc etc. I just wanted a stand alone driver with no worries of dimming. Maybe in the future dimming can be added but for now, I don't dim any of my lights, so why should I care about dimming the LEDs (besides I don't think my AC3 has the capability to dim them).
thermal management
Here's where the picture parts of the build will come into play. I thought about a heatsink from one of those online stores, however I really wanted instant gratification, doubly so since I was in home depot! So I got my weapon of choice. aluminum C-channel, 1/16" thick, 8 feet long (my lights are not going to be that long!) cost about $7 or so.
I forget how wide it is, but it's just wide enough to hold one of the LEDs which is what I wanted.
Not sure if this is going to enough surface area/mass to pull heat away, but more on this later
Drilled some holes for the screws to hold each star onto it.
Lesson Learned: Get a drill press! So much easier to do, while the drill didn't ride on the surface when I finally punched through the whole drill went too and I dinked the aluminum quite a bit.
More holes.... what are these for?
Remember I did not want any strip lights (t5s) this allows me to go modular with my LEDs, so I could change them how I see fit. Different color strips, or even if there's not enough thermal management I could put empty ones in between to add to the overall mass/surface area of the sink. I did however plan to actively cool it with a fan if needed, which is why I made this 4 wide. (I could go more, but I wanted to cool this not the surface of my water.
Finally put all the SOBs on there. Everything wired, only the 3 on each bar are wired together, each bar has its own wires so that if I decide to change bars I can do so without needing to unsolder wires from the LED.
Lesson's Learned: Go with machined screws instead of sheet metal screws, while these hold into the aluminum my palm has a blister on it from having to push down and turn to get these in. The need to put nuts on each machine screw might be worth the extra effort, plus the holes don't have to be as exactly sized. The other thing I didn't realize is these are galvenized/zinc screws, they will rust, I might have to change them out for stainless, although my plan is to have an acrylic shield over the whole thing anyways.
BAMMO! Let their be light! Ok in reality you can't tell how bright this is, because the CCD got oversatured a bit. However the fact I walked around with 12 dots in my vision for a few minutes afterwards tells me it's nice and bright
There are still a few things that need to be done, after a few minutes the aluminum is warm to the touch (not hot mind you), but who knows what it'll feel like after a few hours. I need to get one of those IR thermometers to do some further testing, both on the aluminum (to see if I do in fact need the fan) but also on the LEDs themselves as I want to make sure there's good thermal contact between them and the aluminum.
The aforementioned acrylic shield also needs to be built.. in fact an entire housing I'm guessing, as I need to figure out a way to hang the fixture too. My plan is to drill holes in the shield just enough to to fit the lenses through, perhaps with a rubber gasket simply so there's no additional loss of light.. but we'll see!
Also need to clean up some of the solder joints, its hard to see these things as it is plus when you're temporarily blinded by the brightness noticing the solder joints is a tad difficult
However with that said, I have a rather large summer time "Honey Do" list, so the end result it might be a while before I get this over the tank
Overall though, this is probably twice as bright as the PAR38 fixtures, at around the same price (when all is said and done), so you're not going to save a ton of money, however if I only needed one or two of those PAR38 bulbs it would have been a no brainer to simply buy them.
