DIY Parallel 72W LED Fixture

I'm in the process of going all LED over my 75G reef. That will be a 72 LED build totaling 216W of LED goodness. But since I hadn't ever built a light in parallel I figured I better get some practice. So I used my existing DIY frag light as a guinea pig.

I'm not going to get into the particulars of wiring in parallel here because I'm also writing an article on the subject for one of the sites I contribute to. But I'll show some pics and tell you a little bit about it.

I started with this 14 LED DIY fixture. I figured if I burned something up it wouldn't matter to much, I'd just move my frags into the DT. I added another 10 LEDs.
They are in 2 parallel strings of twelve.
The driver is a MeanWell 60-48D, dimming is with a pot.
Each string has 2 True Violet, 1 Neutral White, 1 Cool White and 8 Royal Blues.

I always hated this ugly hood I originally built.

This new improved heat sink support is perfect. Call me crazy but I love that raw DIY look of bare aluminum tubing. Always have. The support for the heatsinks on the big build will be bare too.



I really like the Berquist Thermal Pads. They hold very well and there's no mess from adhesive. It takes a little work to get adhered LED's loose but they and the heat sink clean up nice.

And heres the all of the LED's wired and soldered.

After getting it all tested for continuity and shorts I powered it up and began checking the forward voltage of every led in the strings. Once that was complete I got ready to adjust the driver to 1.3A. Since it's parallel that number should be spit in half and each string should be drawing 650mA. This is so simple, much easier than adjusting the internal pot in a series set up. You simply turn the external pot all the way up, the SVR2 all the way down and place the probes of your meter (set to read volts dc) on either side of each resistor. With the SVR2 all the way down the readings on each string were identical. I adjusted up to 650mA per string and rechecked. String 1 read 648mA because this is the string I used to adjust the SVR2. String 2 was no longer perfectly balanced with 1 but the difference was only -9mA which is perfectly acceptable. I was done.

Not quite. I still had to attach the pot, fan jack and run the wires permanently.

That black wire cover is Basilik expandable wire sheathing. That stuff kicks ass! Don't ever use that split sheath again! All of the wiring is slid through the Basilik and it looks so nice.
Here's a shot of the fan. The place I got the sticky pad and zip ties from calls them fan mounting kits. PFFT. Any fool knows they are Ecotech Marine wire management kits. LOL

So here it is lit up on my table. It stands 8" tall. I was pretty impressed with the PAR. If you're having trouble reading the meter it reads 744.

And here it back on the frag tank.

I got over zealous and adjusted it up to 748mA per string. I'll have to adjust it back down tomorrow. With the pot all the way up the driver got pretty hot in just a couple hours. But I really wish I could leave it there. PAR is insane!

At the water line....872
Mid water column....419
On the frag rack...208....this is about 14 inches below the lights.

*Afterthought: I have one more order to place with Rapid before I have all the stuff I need for the big build. Just for poops and grins I'm going to order some 60 degree optics for these lights. I want to see how high I can get PAR.

 

Looks really nice! I also like the look of bare aluminum ;D

 

The build looks great! Nice job!

 

Nice

 

Great Work ....

 

Looks GRRRREEEEAAAATTTTT!!!!!

 

I added a photo of the driver, fuses and resistors. Each string is protected by a 1A quick blow fuse and 5W 1 ohm resistor.

 

Terrible Mike, what a miserable fixture.



PSYCH I love it just dont let your head get too big!

 

Looks good. My only suggestion would be, if you are in a humid climate, the added humidity could corrode the bare aluminum. Clear coat or anodize to stop that from happening. Just my $.02.

 

Well it isn't a Radion which if I could afford would be hanging on the tank and over the frag tank as well. But it will work well. Thanks for the comp.

Noted. I'll keep an eye on it especially since directly over open water is about as humid an area as one could get.