LED Retrofit for 24G Nano Hood

[Runner]

I just completed retrofitting my JBJ Lighting 24G Nano hood with LEDs. I gutted everything out of the hood and set up the wiring to use the existing two openings and strain reliefs. I got some good advice from an excellent DIY forum in an otherwise draconian-managed reef site (not this one). But I thought I'd take the opportunity to post this here and increase my traffic here a bit.

The basic LED fixture is a 6" x 9" aluminum heat sink with six (6) Cree 3W XP-G White and ten (10) XR-E Royal Blue LEDs mounted on it. I drilled and and tapped for 4-40 screws and used nylon screws to attached the LEDS. To increase heat transfer, I applied Arctic Silver thermal paste between the starboards and the heatsink.

For the LED interconnections I used used 26 AWG stranded UL1007 wire (rated at 105C) to connect a string of 6 white and 6 blue LEDs. I pre-tinned the wires to keep the "touch-time" down between my butane soldering iron tip and the LED star board pads. I went on to connect the other 4 blue LEDs on another circuit. The thing that looks like a spider in the below photo was a dead LED that I used to practice soldering before I did the work on the real thing...

I then measured off the correct dimensions for my acrylic cover. The cover was sized to fit between screw posts in the hood. I did not span the entire width of the hood because I wanted to bypass the existing air-intake vents. The plan at that time was to cut new vents directly over the heatsink fins.

I used a table saw armed with a plastic-cutting blade to cut the face plate and the side panels of the acrylic cover. I buffed out the scratches on the main cover facing and then taped everything into roughly the proper shape -- leaving a little overhang to be routed off flush later...

After leaching in the Weld On 4 into the cracks of the plastic, I applied pressure with the largest books I had available. I am not sure Wayne Grudem would approve...

After welding the acrylic together, I protected the cover plate with painting tape and used a router to trim off the excess. I then used a piece of paper to trace out the rough shape of the hood profile. I transfered this to a piece of wood that was roughly the width of the acrylic and routed it into the approximate shape needed to fit in the hood. After I was satisfied with the fit, I transfered the shape to the plastic and routed it using the wood as a guide as much as possible.

After routing both sides, I used a table saw to cut the front and back sides down to the proper height. My intent is a 3/8" overhang below the hood -- which gives me about 1/4" to 1/2" clearance over the water. I used the table saw to cut out holes for the fans and cables after marking the proper locations. The end result fit snug enough that I am not worried about the effect of the air leaks.

 

[Runner]

I couldn't find 2-1/4" #4 sheet metal screws and therefore could not support the acrylic cover like I intended. So I welded (#4) and cemented (#15) feet to three locations (added a 4th later) and put screw holes over the hood posts. This allows me to use 1/2" #4 screws. I could only do three feet because the 4th location has a missing screw post.

I put holes for screws wherever I could find a usable screw post in the hood and secured the heatsink inside the hood. I then tidied up the wiring some. I ended up only needed to add one cable support inside the hood.

I decided to place all the ancillary equipment in a larger box, but stopped short of shelling out $80 for a true control panel. I put in my two constant current drivers and a bunch of old terminal blocks and switches and strain reliefs I've had laying around. The 120 VAC stuff is on the left and the low-voltage stuff is on the right. This pic is the work in progress: the only thing missing is the low voltage connections to the hood.

It doesn't show in the picture, but I went on to add three more small holes in the right side and force grommets into them. These holes were for the 9VDC power supply. One was for temporary power to keep the ELN-60-48D at a decent voltage level and two were for the two LED circuits.

I then calibrated the current loop to be as close to 1.000 A as I felt safe...

Adjusting the current driver pot:

As you can see, I got fairly close. Over 1A will burn out my XR-E royal blue LEDS:

I then cut holes over the heat sink for ventilation. I decided to go with the easier drilling "cheese grater" look than risk messing up the hood routing in slits.

Here is the (mostly) final product. I had to go back and a 4th acrylic foot and add through-the-hood screws to hold the acrylic cover because the hood screw posts that hold the acrylic cover were cracking. I used black screw covers for them, though, so they do not look too bad from the top.

Finally, I cleaned out my stand and installed it all underneath.

Here is the tank with all lights:

...and only blue lights:

I need to get a PAR meter back from our club again so I can see how things have changed. The old tank under two 36W PCs was at these levels:

The only thing that bothers me about this setup is that the lights have moved back in my tank by about 2" or 3" and my back wall has more direct lighting on it. The mushrooms there were deciding it was time to run away and my Duncan in the front was in lower light now and is acting like it is night time. I gave it a day or two and, but then rearranged the rock to push it back. Things are much happier now.

 

[evilc66]

Very nicely done.

 

[seafansar]

Looks really good. I wish I was that handy with DIY stuff!

 

[NanoNano]

Looks really good. I wish I was that handy with DIY stuff!

Me too. I can barely cook a frozen pizza. That is a really nice job.

 

[sprinklerdudes]

good job, clean wiring make a good look under the cabnet

 

[wld1783]

Awesome

 

[Runner]

Thanks. I had a lot of fun doing this. But my wife is glad I am done. The basement sure is a lot cleaner now, anyway. :)

I finally go ahold of our club PAR meter and was shocked to get the following results:

As I said above, I did move the rock back a couple inches and rearranged a few things to put some of the corals more under the light. The lower values towards the bottom of the pic are because the rock is forward and not directly under the light. But basically I have metal-halide intensity in the middle with only 48W of LEDs. In the center of the fixture about 2" under water I have 1100 PAR. Typical values around the fixture are 600 to 400 PAR at depths of 4 to 8 inches. The blue LEDs put out just as much par as the white even though they only have 1/3 the lumens. My four royal blue LED "morning and evening effect" lights are enough to make most of my corals open.​

 

[reefsmokinFOOL]

Yea i would agree with shocked. Those par values are crazy with only 48 watts. Great build btw

 

[Runner]

Good grief. Thought my thread had been deleted. Took me forever to find it. :)

Then I saw the BIG banner for the new LED forum and that rusty thing called "logic" kicked in and led me here... :D

 

[Runner]

I just finished writing this up on the East Tennessee Reef Club website at this link. Please take a look and let me know what you think.

 

[revhtree Verified Admin]

Dude this is sweet!

 

[Runner]

Thanks, Rev. :)

I've had some noticeable growth since I put in the LEDs. And a few deaths as well (like the purple-tip hammer) that did not like the light increase. Here is my tank now:

Front

Left Side

Here are links to larger pics of the front, left, and right sides.