DIY LED Aquarium Lights


DIY LED Aquarium Lights

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This is my DIY on how to build a LED lighting system from start to finish. This design was based on a thread started by SoundWave[1] on reef central and is very similar to his design. This system is based on a modular design with each module designed to be superior to a 250 watt metal halide lamp[2]. The idea being that you use 1 controller, 1 power supply, and as many modules as you need to light your tank. If you don't want to bother with a controller, you can instead simply use potentiometers to adjust the LED output. This article covers construction of the lights. For construction of the reef controller, see DIY Reef Controller

Source(s): DIY LED Aquarium Lights


[edit] Parts List For My Module


Description Quantity Part No Supplier Unit Price Total Price
Cree Cool White XR-E Q5 LEDs mounted on star boards 16 XR-E Q5 6.00 96.00
Royal Blue XR-E Q5 LEDs mounted on star boards 8 XR-E Q5 6.00 48.00
ETG 40 Degree Lenses and Holders[3] 24 TY-A40F-M15 1.00 24.00
1000mA wired buckpucks w/ Dimming 4 3023-D-E-1000A 16.00 64.00
Nylon Screws 6/32 1/2"[4] 48 NY PMS 632 0050 PH 0.10 4.80
220µF, 50V capacitor 4
12"x8.5" Aluminum Heatsink 1 L0002 26.00 26.00
Cooling Fan[5] 1 Local Computer Store 5.00 5.00
Total For Module 267.80

Power Supply:

For the power supply we need to provide 24V to drive the LED's and 12V to drive the micro controller and fans. I'd like to find a reliable and inexpensive part that will handle this requirement but I settled for a 12.5 Amp 24V power supply and a 24VDC to 12VDC converter. Honestly, I'd like to have found a power supply a little bigger than 12.5 amps. The LED's and drivers will use 12 Amps and the .5 amps remaining isn't much head room to drive the fans and micro controller.

Source(s): DIY LED Aquarium Lights

Description Quantity Part No Supplier Unit Price Total Price
24V Power Supply capable of 4 or more amps per module[6] 1 25.00 25.00
24VDC to 12VDC Converter[7] 1 12.00 12.00
Total For Power Supply 37.00

Other Parts

  • Epoxy
  • Thermal Paste
  • Cooling Fan
  • Aluminum stock
  • Stainless machine screws – I used #6-32
  • 16 gauge wire


  • Drill and tap set
  • Soldering Iron

Source(s): DIY LED Aquarium Lights

[edit] Optics

By themselves, these LED's throw light out over a 90 degree arc which is going to put most of their output on your walls instead of on your corals. I purchased 40 degree optics, which means the light on the bottom of my tank is going to be about twice as strong. I used a little trig to calculate that with these optics each LED is going to put out a cone about 2' in diameter on the sand bed. My lights are going to be hung about 8" above the water, and my tank is about 2'2" from the top of the sand bed to the water line. If you want to hang your lights higher than me, you may want to check out the 25 degree lenses. They throw a pattern 14" in diameter which was too small for me... But if the light is higher, the pattern will get bigger.

The formula I used:

2 * h * Tan(o/2) = p

Where h is the height of the led above the sand bed, o is the degree of the optics, and p is the diameter of the pattern. So a 34 inch height using 40 degree optics will result in a pattern 27.4 inches in diameter on the sand. Please also keep in mind that for 40 degree optics, this refers to the number of degrees at which the light output is half of it's maximum, so these optics do still spill substantial amounts of light outside this pattern. Also, something called Snell's Law should tighten this pattern up, but I don't know by how much, or if it's significant.

[edit] Power Supplies

Each module runs at 24 V and uses 4 amps of power. I will be creating 3 modules, so I will need a power supply that does 24V and 12 amps. When scaling the system up, you increase the number of amps but the voltage stays the same. You can also use multiple power supplies or even one power supply per module. Having a supply rated for too many amps isn't a problem, but too few will cause the power supply to fail. The voltage should be 24V, but a power supply with adjustable voltage may be usefull... If you find that your buckpucks aren't putting out 1 amp at full power you can adjust the power supply a little higher to give them the voltage they need.

Source(s): DIY LED Aquarium Lights

[edit] Possible Design Improvements

  • For large runs, save a $50 on drivers per module by making a PCB and using one of these:

Source(s): DIY LED Aquarium Lights

[edit] Notes

  2. This design uses the same number and type of LED's as the fixture reviewed in This review compared this configuration of LEDs to a 250 watt 20k metal halide fixture and determined them to be superior.
  3. You might need different lenses if you want to hang the fixture from the ceiling. See the optics section
  4. I used screws to hold down my LED's to the heat sink because I wanted to use thermal paste underneath them to keep them cool and extend their life, but this is optional. Others have been successfull using only thermal epoxy, but thermal epoxy is several orders of magnitude a worse conductor than cheap thermal paste.
  5. I don't know if this is strictly required, but I read that the cooler the LED's run the longer they last.
  6. I am using a single supply to drive three sections, so the power supply used in my build is greater than 12 amps
  7. If you're not going to build the DIY Reef Controller this is only used for the fans. You might want to substitute 24V fans instead, or just put two 12V fans in series

Source(s): DIY LED Aquarium Lights

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