DIY LED Lighting Fixture

DoctaQ;

It's been awhile, but I finally had a chance to start working with my CREE xp-g R5's. Wow really nice. I noticed that CREE updated their spec sheet for the xp-g R5's and indicated that you can run them at 1.5 amps. The other thing I noticed is that I have 12 of them strung together on my Meanwell ELN-60-48D @1.5amps and that they are only using about 38.5 volts out of the 48 available. I might go ahead and add a couple more and have 14 instead of the 12. When I get the unit finished I will need to post some images. I converted an old Orbit Current USA 4x65watt unit. I am going to have 24-48 xp-g LED's in the housing. Should be nice and bright. Everything including the MW power supplies fits nicely within the Orbit housing. I am even going to reuse the 4 moon led's that came with the unit.

Sounds interesting. When you get something to show, please do...

I've completed my first CREE xp-g R5 DIY High Powered LED Aquarium Light. These newer CREE LED's are really nice. I used 28 of the CREE xp-g R5 LED's in two circuits with Meanwell ELN-60-48D power supplies. Both circuits are fully dimmable independent of each other. I used an existing 48" Orbit fixture that had 4 - 65W bulbs in it. The unit is running really cool only about 7 degrees above room temperature. For more information you can check out my articles on my blog. This is one of two that I am going to build for my 200 gallon aquarium.

DoctaQ;

Here is a cost breakdown for this fixture, minus the light housing.

LED’s – 28 @ $6.50 each = $184.00
Thermal Pads 28 @ $0.49 each = $13.72
Heat Sinks – 6 @ $11.98 (including shipping) = $71.89
Power Supply LED – 2 @ $26.71 = $53.42
12 Vdc Power Supply (for fans and dimming control) – $15.00
Aluminum angle brackets and flat stock – $22.00
Wire / Solder / Screws / etc. $20.00
Total – ~$380.00

I am always looking for less expensive options. If I compare this light to my previous one (~$250.00) you do get some economies of scale. For one the heat sinks you only need one set for all 28 LED's vs 12 LED's in the previous build. I did find yesterday a surplus shop that has all different types of heat sinks at what appears to be good prices, plus some of the heat sinks are less if you order say 10 of them. I ordered a few different samples to see which ones would work. Again the 12 Vdc power supply, you only need one regardless of the number of circuits. As far as light goes the first unit was around 50W of power. This unit is around 140W of power. I've also decided to use a thermal paste conductor vs the thermal pads. Also some of the newer Orbit fixtures have an updated bracket assembly internal to the fixture that makes the assembly process much easier and I won't have to build brackets to hold the heat sink assembly in place. This will save some cost and time on the aluminum flat stock. I think if I really look at the costs, I can get another $25 - $45 dollars off the cost. The newer CREE xp-g R5 are much brighter and seem to run cooler than the previous CREE xr-e Q5's, which is also a big plus. I am running more than twice the LED's at a lower temp. I think this will let me use a lighter weight heat sink. That is the one negative of this fixture is the weight due to the heat sinks.

I have also thought about putting together a retrofit kit for the Orbit fixtures that I would sell on my website. I am looking into making wiring harnesses that would make the job of connecting the wires much easier. I also have a couple of people (locally) who have asked me for quotes for building them some LED light fixtures.

One other item I forgot to mention was that I compared this unit (140 Watts - LED) to my friends 175 Watt -MH fixture. Here is what I saw. We took both units into his garage which has no windows. We placed the LED light on his saw horses about 3 feet off the ground with the LED's facing the ceiling. We closed the door and turned on my LED fixture. The garage was flooded with light. There were no spots of light it was an even pure white light. Next we did the same with his MH light which was in a dome fixture. Where as the LED light came on at full brightness, we had to wait around 4 minutes for the MH light to reach full brightness. The light from the MH bulb was a bit more blue-white and because of the dome fixture the light was more of a spot on the ceiling. As far as brightness, and this is my observation, the LED light was brighter and lit up a larger area. Now how does this translate to an aquarium. With the MH light he has two of the fixtures over a 6 foot tank. The areas beneath the lights are well lit, but the center between the light fixtures tends to be dark. With the LED light over my aquarium there are no dark areas or spots of light in the aquarium. With the LED's spread out over an area of about 4 feet long x 6 " wide, the aquarium is flooded with light.

Yes, I am using the berquest thermal pads. I thought I needed to screw them down. If not that would save a bunch of time.

The reason the picture with the plants looks yellow is because of the wood I put in the aquarium. Even though I boiled it, it is still releasing tannins into the water and making everything look yellow. I did a 50% water change and that cleared it up a bunch. Still need to do another 50% tomorrow and that should help even more.

This aquarium is just planted, but my 55 gallon with mineralized soil, CO2 and the LED lights is growing at an unbelievable rate. For example, my crypt wendtii-red. I started with three plants. After about 3 months I uprooted them along with the new plants and replanted 15 plants. A month later I gave away 2 large clumps that were 18" tall and each one could have been split into 6-8 nice size plants. I then pulled up some of the plants pulled off the babies and replanted them and another 20 babies which are now starting to get to a nice size.

Additionally it seems like my fish look so much more healthy in 55 gallon. It maybe due to the plants keeping the water parameters so good or it maybe the lights themselves. Either way the only lights I am going to use are the LED's on my aquariums.

As for the resistor circuit, your right I might want to look into something better. I was looking at a new Meanwell LED PS that will allow you to just hook up a potentiometer across the dimming circuit to control the output. Not sure when it is going to be available yet.