Taqpol's DIY LED prototype build, detailed pictures, and PAR readings!

[Taqpol]

I actually started this build thread on another forum but i wanted to go ahead and post it here as well! Most of these posts are direct quotations from the old thread and might not mae sense out of context, so if there is any questions please let me know!

In May I am going to be moving to North Carolina and upgrading my tank at the same time. As of now the current plan is to have a 180 gallon tank lit with four blocks of 24 3w Cree XR-E's (spotlighting two major islands) and another one or two strips of 24 LEDs for coverage in the middle of the tank. On top of all of that I am contemplating building my own Arduino controller and using 8 channels of PWM to simulate sunrise and sunset over the reef. Before I got too deep into all of this I wanted to build my own test fixture so I could actually hold it in my hands to see what was what.

I ordered a 24 LED (12 cool white, 12 royal blue) kit from www.rapidled.com and an 8.4"x10" aluminum heatsink from www.heatsinkusa.com on Monday night and both packages arrived here today! The LEDs will be driven by two Meanwell ELN-60-48P drivers.

 

[Taqpol]

I got a lot done today, but like all of these projects I did think i would get even farther.

Marked out the LED placement, I used roughly 1.75" between LEDs and 2" between rows:

Blue LEDs in place for a sense of scale:

I then drilled 1/8" holes through the heatsink on either side of where an LED will end up. This will allow me to pass wires through the heat sink and hide everything in the fins:

I also ground down some perpendicular channels so I can pass wires between the fins without going up and over:

Turtle Wax Polishing Compound was used to buff out any scratches and give a better surface for heat transfer. Right before I mounted the LEDs I also wiped down the surface with isopropanol and a lint free cloth:

RapidLed's kit came with Arctic Alumina Thermal compound so I used it. Like all two part epoxies you mix it in a 1:1 ratio on some kind of plastic sheet (I wax paper):

I then used the provided spatula to apply some mixed compound to the underside of the LED star, after I wiped it down with isopropanol and a lint free cloth:

Press it into place on the heatsink. A slight twisting motion as you apply pressure really makes sure the thermal compound fills up all the imperfections:

I think I used a bit too much. One things for sure, these puppies are not coming off anytime soon:

Finished fixture:

 

[Taqpol]

Touch the pre tinned soldering iron to the solder on one side of the pad:

Move the solder away and feed it in at a good clip until you get a nice mound:

I used a 30 watt soldering iron for everything I did today.

I decided to use stugray's dimming circuit method as it did seem easier to me. Here was my proof of concept involving two 5Kohm pots and gator clips.

While testing voltage across my second pot, I use the first pot to adust my maximum voltage. This is being fed by a 12v wall wart that was producing 12.1v on its own:

Then I wired it up so the multimeter would see what the meanwells dimming circuit sees. The wiring goes like this:

Wall wart positive -> 1st pot high side
1st pot wiper -> 2nd pot high side
1st pot low side -> unconnected

2nd pot wiper -> Meanwell DIM+ (multimeter positive)
2nd pot low side -> wall wart negative

Meanwell DIM- (multimeter negative) -> wall wart negative

Note that the 2nd pots low side and the DIM- both connect to wall wart negative.

Using this setup I was able to get any voltage from 10v to 0.0v:

Of course I wasn't content to leave it simple. I proceeded to make a circuit that would take my 12V wall wart and power a computer fan as well as the master pot and two 0-10v pots in parallel to control both of my Meanwells:

This board, along with my meanwells, will be mounted in a radio shack project box with the adjustable pots sticking through the case for use as an "external ballast".

 

[Taqpol]

This is coming along really fast! I forgot how much I enjoy soldering and electricity stuff.

ALL of the blue LEDs wired in series!

Wiring hidden in the fins:

With all that done and my voltage regulator working, its time to wire up some drivers!

Standard AC power chord, soldered and heat shrink'ed with a lighter:

Hooked everything up with aligator clips. With no LEDs the driver was producing almost exactly 48V!

 

[Taqpol]

As suggested I hooked my multimeter up in series with the LEDs after turning the SVR2 pot down all the way (counter-clockwise). It turns out my multimeter does work just fine after I switched the positive chord to the 10A socket.

Lights! with my dimming circuit on full blast (10V) and the SVR2 pot all the way down the rig only drew 0.15A yet I was still seeing spots.

Adjusted the SVR2 pot until my amp meter read 0.7A, this level is almost blinding without optics!

The lowest I can go with my dimming circuit pot is 0.09A, it will shut off after this.

60 degree optics, fully dimmed.

60 degree optics, full power.

The ceiling above me. I am really impressed by the spread of 60 degree optics.

 

[Taqpol]

Well, technically the array is done! Talk about a weekend project, now I just have a bunch of finishing touches to add.

I highly suggest getting one of these 2x AAA battery testers from radio shack if you're going to do a LED build. I was able to test every connection as I soldered them in instead of having to go back at the end and find out where the bad solder joint was!

700mA. I might go up to 850mA, but I think I'll wait until I can get my hands on a PAR meter to see what kind of difference it actually makes.

I think I still have spots in my eyes:

I've been using my fiancee's point and shoot camera for all of the documentation pictures. It really doesn't capture the true color at all (Way overpowered by the blue) so sometime here I'll break out the SLR and play with the color temperature settings. All LEDs running

Only blues (+60 degree optics)

Only whites

Both. Again, this image is skewed to the blue side but by looking at the two previous pictures you can see how the white smooths it out.

 

[Taqpol]

Some updates on the LED front!

I went ahead and put silicone in the wire channel running perpendicular to the heatsink fins. I think my problem before was i overtightened the fan mounting rails, but this will still put my mind at ease.

Lifted wires out of the channels:

Silicone bead:

Mounted fan and fan rails. The silicone is completely hidden from view:

Also, I did manage to fit everything in my project box. Barely.

Technically everything is done!

Unfortunately it does not work with the 6' nine pin serial cable I picked up. I'm pretty sure this is due to the wires in the serial cable crossing over, whereas in my prototype cable the far left pin would match the far left pin of the cable below it. Good news is, the way I used the nine pins I'm pretty sure I can just flip all of my internal cables around to make the mirror image and it will work fine. Good thing I used quick disconnects instead of soldering...


Also, does someone that owns a meanwell also own a kill-a-watt meter? I would like to see if you turned the dimming circuit off if the driver itself draws any power while plugged in.

 

[Taqpol]

I've been very busy this weekend, but I think i have something that everyone will enjoy.


PAR Meter Time!!!


I started out with a simple rig to hold the LEDs 36" off of the ground. All the blue tape you see on the floor marks off 6" in every direction, so I have 25 data points over a 24"x24" area.

Here it is with the LEDs on, with no optics. Without optics I'd say the spread on the floor is a circle a good eight feet in diameter. As you'll see in my data later on, I think its pretty stupid to not use optics on your LEDs unless you are going to mount them ridiculously close to the surface of the water.

Now we have it with the 60 degree optics back on. This setup lights a 24" diameter circle extremely well, but I'd say the coverage of noticeable light is around 30"x30" which is good for my 30" deep tank.

 

[Taqpol]

Now I'm just going to throw data at you. Be prepared!

Raw data that all of my charts are based off of:

Graphs for spread with no optics, and the distance of the PAR meter away from the fixture:

Side by Side comparisons:

More of the same, with 60 degree optics:

 

[Taqpol]

Last but not least, I even have some water shots!

I was so scared of my shoddy PVC rack dumping the entire fixture in the tank, but it did well! I think the PVC legs might have blocked light to some areas of the tank, but here goes:

While the spread seems to cover more a full 24" of the tank, I would not feel comfortable with only two fixtures over this tank as I would feel there would be a major gap of lighting in the middle. Plus the PAR in the center would be atrocious with 60 degree optics. Three fixtures would have great coverage and good PAR, four would have perfect coverage and amazing PAR.


I also tried to take some close up shots to show the color rendition of my corals. I tell you, this was a pain and took a LOT of post-processing in photoshop. The light was so focused it absolutely washed out my candy cane and any corals around it so I had to burn it in before I was able to play with the kelvin rating.

This is with both strings at full power (700 mA). Photoshop has it pegged right at 10000K, and unfortunately it looks a tad to pinkish for me.

I then adjusted the whites down in intensity. Photoshop has this at 20000K and I think it is much closer to what I am running with my T5 setup.

Actinic: Twelve blues at full power, no whites. I think it is impossible to get photoshop to take an accurate picture of this (I had it maxed out at 50000K and still had to mess with the purple/magenta hues) but I can't believe the pop and actinic glow it gave the corals. Not natural looking at all, but jaw-dropping nonetheless.

Under Water PAR time!

The number in red is the PAR with the meter just barely sticking out of the water (the lights are suspended 12" above that). Every other number is supposed to be for the vicinity around the coral they are in front of.

100%, both strings

100%, Royal Blues Only

And my T5's for comparison. I was shocked at how low the T5 numbers are, but I have to say I have been getting great growth and color out of all of my corals. Needless to say, the LEDs blew them out of the water!

 

[Taqpol]

Thoughts...

Hands down, use optics. If you look at my raw data in the "in air" section you'll see that at 36" away from the emitter I was getting roughly 30 PAR around the perimeter of my testing area. Now go to the with optics data and you'll see that I'm still getting ~30 PAR on the perimeter, but it peaks at 252 PAR instead of a measly 53 dead center. Compare the two dead center at 12" from the emitter and you get 997 vs. 380. That being said, my perimeter readings at 12" from the emitter with optics were right around ~6 PAR. This was the background PAR for the room i was testing in so basically they were not getting any light there. You can see this effect in my FTS, but with three emitters over the tank I think this effect would be completely neutralized.

T5's are weird. Sticking the meter out of the surface got me PAR readings of 398 max with T5 compared to my LED max of 912. That being said, the LEDs dropped down to ~100 PAR around the edges of the tank on the sand bed, whereas the T5's maintained consistent 200 PAR ranges all over the sandbed but really peaked around 300 where my corals are. Regardless, I will most definitely have to light acclimate my corals to these, especially when I have two emitters per island.

Also, color. Color and perception of color is a very personal thing, and it is extremely hard to capture it perfectly in an image when it is so biased to one range. Still, the pinkish color kind of bugs me. It might be something that I will just end up getting used to, but as of right now I think i will be modifying my bulb ratios to something like 8 cool whites to 16 royal blues, especially since my royal blues appeared to put out a good amount of PAR. I could also try running the cool whites at 700mA and the royal blues at 1000mA, but i don't know how noticeable that would be. If I don't like this amount of white I don't even know what i would have done had I gone with the XP-G cool whites!

Lastly, shimmer. This fixture definitely has it but I don't know how I feel about it yet. It seems cool, but it feels like it almost overpowers the tank itself. This might just be because I have NEVER owned a fish tank without fluorescent lighting. Also, I might be crazy but it seems like it might make it harder to photograph as well. I tried a few different things but none of the LED pictures above appear as crisp as my T5 FTS.

Let me know what you guys think!

 

[MGDMIRAGE]

Excellent work, i can't wait to see more of this project!

 

[Taqpol]

www.rapidled.com

www.heatsinkusa.com

Radio Shack

 

[MGDMIRAGE]

Sorry i had gotten lost in the pictures, i should have read more lol. It looks great but the one thing i've noticed with LEDs is the colors don't seem to blend together very well and typically you will still see the individual colors of each LED on the rocks. That being said it's still a project i wish to undertake as i feel LEDs will be the future of reef lighting and their ability to dim makes them that much more awesome.

 

[iroll253]

OMG this is the most informative build thread i have seen on multiple forums :drool:

I have some questions to pm you about

 

[seattle989]

you my friend are a god.

 

[Skimmy]

wow... excellent build thread!!

do you have plans to make an enclosure for your fixture? or is it going to be in a canopy?
sorry if you answered this and i missed it.

 

[thatguy559]

this is the best build thread thus far....great job you have inspired me to build my own!!!

 

[Taqpol]

Sorry i had gotten lost in the pictures, i should have read more lol. It looks great but the one thing i've noticed with LEDs is the colors don't seem to blend together very well and typically you will still see the individual colors of each LED on the rocks. That being said it's still a project i wish to undertake as i feel LEDs will be the future of reef lighting and their ability to dim makes them that much more awesome.

I think the blending issue might just be an artifact of photography, unless you've seen them in person. If you look at the above "FTS" you can definitely see individual blue beams and white beams going through the sandbed, but in person this effect was hardly noticeable! It also all depends on your optics and how high you mount them from the tank. I just ordered some 80 degree optics that I expect to give me even better coverage and blending, but I want to see if I can use them without sacrificing too much PAR.

The dimming is very cool, and it makes for acclimating corals (which you will definitely need to do) a snap. For my actual tank fixture I am planning on ordering "D" models and dimming them individually with an APEX controller so that I will have a sunrise/sunset effect that starts with actinic and goes left to right across my fixtures, then the whites will come on left to right.

 

[Taqpol]

you my friend are a god.

Hahaha, there are much better build threads out their then my own!

this is the best build thread thus far....great job you have inspired me to build my own!!!

Thats great! The more people out there building their own LED fixtures the faster the technology and implementation will advance. The main reason commercial fixtures are so expensive is the time they spend in R&D, but DIYing them the costs aren't too much worse then brand new MH systems. Factor in the cost of no bulb replacements for 5-11 YEARS and the thing will pay for itself!

wow... excellent build thread!!

do you have plans to make an enclosure for your fixture? or is it going to be in a canopy?
sorry if you answered this and i missed it.

This one I have is definitely a prototype, I just wanted to get a fixture in my hands, see what the color was like, and hopefully test some PAR, all of which I have done.

I think this prototype might end up going over my cube anemone tank. In that case I would build some kind of black acrylic box around it so that it looked more like a fixture. For my future tank itself I plan on mounting the heat sinks directly to the canopy with a low profile fan and the heat sink fins sticking out into the room. and the bulbs and optics completely hidden.