As with any DIY project there are 100 ways to do it. Be creative and adjust it to your needs. Below is how I chose to build two 70watt, HQI (double ended) with electronic ballast. I'm not the creator of this idea but I added some features I felt were missing from the original design. Mainly, quick connects from the lights to the ballast and an enclosed ballast to protect the electronics and wiring from spills and splashes.
WARNING! Electricity can kill you and start fires! Please use this DIY with extreme caution. You do not have to be an electrician to complete this project; however, you need to be familiar with basic electrical safety and concepts. Do not power up any portion of this project until the entire project is complete.
Parts list (for one fixture)
· Outdoor Halogen Flood light 300 or 500 watt ($11)
· Electronic Ballast ($30)
· 2 Extension cords – length based on your needs ($15-20)
· Electronics Enclosure (electrical section at Home Depot – size depends on ballast) ($7-20)
· Metal Halide bulb ($19-110)
· Wire nuts and electrical tape ($2)
· Wire clamps ($2)
· Optional – fan
Wiring the lights
Wiring the Ballast
I was building a two light system so the pictures show a large enclosure and two ballasts.
This is a simple schematic of the how one ballast is wired on my setup. All ballast will be similar but may have different colored wires. Follow the instructions included with the ballast.
OPTIONAL FAN: I had an extra fan lying around so I thought I'd add it. I've own several store bought metal halides none of which had fans on the ballast. They all did have air vents or fins to dissipate the heat. With the fan it does not get hot at all. I don’t know how hot the box will get without the fan. If you use a fan make sure you purchase an enclosure large enough to house the fan and ballast.
Cut hole in lid the size of the fan and mount fan.
Secure lid to enclosure.
The female plug on the lights will connect to the short cord with the male plug on the enclosure (Quick Connect). DO NOT plug the short cord into the wall outlet or run the ballast without the lights connected, this may destroy the ballast.
Ballast enclosure mounted in stand. I use timers to control my lights so I did not add a power switch.
Light mounted in canopy (you can test the lights to verify they work before mounting them)
Some info about Metal Halide
WARNING! Electricity can kill you and start fires! Please use this DIY with extreme caution. You do not have to be an electrician to complete this project; however, you need to be familiar with basic electrical safety and concepts. Do not power up any portion of this project until the entire project is complete.
Parts list (for one fixture)
· Outdoor Halogen Flood light 300 or 500 watt ($11)
· Electronic Ballast ($30)
· 2 Extension cords – length based on your needs ($15-20)
· Electronics Enclosure (electrical section at Home Depot – size depends on ballast) ($7-20)
· Metal Halide bulb ($19-110)
· Wire nuts and electrical tape ($2)
· Wire clamps ($2)
· Optional – fan
Wiring the lights
- Cut the first extension cord in two pieces approximately 12" from the male plug
- At the cut end of the extension cord, strip the individual wires ends (on both pieces)
- Connect the long cord with the female plug to the light fixture using wire nuts. Black to black, white to white, green to green NOTE: the green wire is "ground", the light fixture may not have a green wire, if it has a bare copper wire then connect the green wire to the bare copper wire.
- Once the wire nuts are in place wrap them with electrical tape as a water barrier.
- Cut a hole in the side of the light base to run the wire and allow the base to mount flush. A Dermal will make short work of this step. File and tape the edges of the base where you cut to protect the cord.
Wiring the Ballast
I was building a two light system so the pictures show a large enclosure and two ballasts.
- Drill holes in electronics enclosure the size of the wire clamps (bottom). Drill smaller holes on two other sides to act as vents. If you are only installing one ballast you will only need two large holes for wire clamps. NOTE: if not installing the optional fan I would recommend making the side holes larger.
- Install wire clamps
- Cut the female plug off the second extension cord and strip the wires on the piece with the male plug; just as you did in step 2 on the first extension cord. You can discard the female plug.
- Run the short extension cord with the male plug (from Step 1) and the long extension cord with the male plug (from Step 8) through the wire clamps (do not tighten the clamps). All of the cords coming form the enclosure should have male plugs. The short cords will go to the lights. The long cords will go to the wall outlet (do not plug in to wall outlet until project is compete).
- Install the ballast in the enclosure and connect the wiring per the ballast instructions; then tighten wire clamps. The ballast should be secured to the enclosure with screws.
This is a simple schematic of the how one ballast is wired on my setup. All ballast will be similar but may have different colored wires. Follow the instructions included with the ballast.
OPTIONAL FAN: I had an extra fan lying around so I thought I'd add it. I've own several store bought metal halides none of which had fans on the ballast. They all did have air vents or fins to dissipate the heat. With the fan it does not get hot at all. I don’t know how hot the box will get without the fan. If you use a fan make sure you purchase an enclosure large enough to house the fan and ballast.
Cut hole in lid the size of the fan and mount fan.
Secure lid to enclosure.
The female plug on the lights will connect to the short cord with the male plug on the enclosure (Quick Connect). DO NOT plug the short cord into the wall outlet or run the ballast without the lights connected, this may destroy the ballast.
Ballast enclosure mounted in stand. I use timers to control my lights so I did not add a power switch.
Light mounted in canopy (you can test the lights to verify they work before mounting them)
Some info about Metal Halide
- They produce a lot of heat
- The bulbs need to be replaced every year
- This is not necessary with freshwater fish only tanks. I have used the same bulb for 5 years until it burnt out without it hindering my viewing pleasure. The color temperature will shift to the red side of the spectrum over time, meaning the light will look more yellow than a new bulb. If you have more than one bulb I would recommend replacing all at once. If the other bulbs are old the new one will be noticeably brighter and probably have a slightly different color. I didn't find the need to replace the bulb for plants either; however, a serious planted tank enthusiast would have to decide for themselves.
- One Metal Halide bulb for every 2 feet of tank.
- Like the above rule this is more for saltwater corals. It does apply to freshwater in that you need one every 2 feet to get complete coverage of the tank. If you like to play with light effects you can use half the recommend amount of bulbs (or fixtures) to create shadow areas on the ends of the tank. I discovered on this project that when mounted on the side of the tank and face towards the center (instead of down) they will fully cover 3 feet of tank allowing 2 bulbs to illuminate the entire 6 foot tank.
- The price of this project will depend on the type and quality of bulb you use. I chose a mid-grade bulb that cost $45ea
- 5500k, 6700k, 10000k, 14000k, 20000k are the most popular bulbs for lighting aquaria. Inexpensive bulbs with a color temperature of 3200-4200k will look very yellow on an aquarium.
- Common wattages for Aquariums are 70w, 150w, 175w, 250, 400w and 1000w (you better have a big tank)
- I recommend staying away from the 100w fixtures, these are hard to find suitable bulbs from aquarium use – unless you are looking for light in the 3200-4200k range.
- Ballast larger than 70w will increase the price of the project.
- If building a light larger than 70w check the bulb size to verify it will fit in the fixture socket.
