Print PDF
Favorite
Email
Got a dark closet with no room for a light? This Instructable presents one way to solve the problem: a low profile array of high intensity LEDs mounted in aluminum channel. Simple, effective, cheaper and better than what you can buy out in the market currently. I wanted a 60 inch span outputting a total of around 1000 lumens. There were a few options out there, but none fit the bill. Also, none allowed me to design and build my own light and live to tell the tale.
I looked into buying Elara strips but since they are $20 apiece I would need to spend $100 to span my 5 foot wide closet and still need to buy and mount to a heatsink and get a power supply. Additionally, the warm white Elara strips are about 130 lumens per foot which would give only 650 lumens for the whole array and at pretty poor efficiency (<50 lumens per Watt before power supply losses). The more powerful Luxstrip II strips output in the neighborhood of 500 lumens per foot at 350mA which is too much for my application and at $45 per foot would be even more painful on the wallet. A heatsink and power supply are also required.
After careful consideration, I determined that purchasing single high efficiency Cree XPG warm white LEDs on star boards and mounting them to a heatsink and providing a constant current driver would be more cost effective and yield superior results.
I looked into buying Elara strips but since they are $20 apiece I would need to spend $100 to span my 5 foot wide closet and still need to buy and mount to a heatsink and get a power supply. Additionally, the warm white Elara strips are about 130 lumens per foot which would give only 650 lumens for the whole array and at pretty poor efficiency (<50 lumens per Watt before power supply losses). The more powerful Luxstrip II strips output in the neighborhood of 500 lumens per foot at 350mA which is too much for my application and at $45 per foot would be even more painful on the wallet. A heatsink and power supply are also required.
After careful consideration, I determined that purchasing single high efficiency Cree XPG warm white LEDs on star boards and mounting them to a heatsink and providing a constant current driver would be more cost effective and yield superior results.
Remove these ads by
Signing UpStep 1Materials
This build is pretty basic. The light fixture is the heat sink, and the rest is just LEDs, mounting, driver, and wiring. I'm still working on a diffuser but after having the light installed for a while I kind of like the look of the bare LEDs. Total cost was about $100. A note on the driver, this is a small and cheap driver but it is not UL listed, is not dimmable, and generates some interference in my experience. So if you are trying to listen to a far off radio station, turn this light off.
Materials:
8 feet of 3/4" wide by 1/8" thick aluminum channel from McMaster Carr ($13.70)
11 Indus star boards with warm white Cree XPG LED ($6.05 x 11 = $66.55)
16W 320mA constant current LED driver ($7.60)
22 4-40 screws
Suitable wire
Thermal compound
Heat shrink tubing
Tools:
Drill
Drill bit and tap for 4-40 threads
Soldering iron
Solder
Screwdriver
Hot glue gun
Aviation snips
File
Multimeter
| « Previous Step | Download PDFView All Steps | Next Step » |
b) The linked LEDs are Cree XPG, which can run at 1500mA if heat sinked appropriately. Using the driver shown at the 320mA drive current there are no options outside of Cree XML that will give "higher power" at the shown drive current. The XML will just output about 15-20% more light at the given 320mA but cost about double. The reason I went with the low current drive is two-fold. First the U-channel is not an adequate heat sink for high power. You could probably drive the XPGs at 500mA at the spacing shown without damaging the LEDs but I wouldn't go much higher. The second reason is that driving the LEDs at a higher current will increase the light output by each LED. I wanted a linear, more dispersed light output where each LED was not running so bright that it would blind you. With 11 XPG LEDs in series like this I could put out 3000 lumens if I wanted to, but with each LED running at >3W the LEDs would be blinding. If in your application you will not be able to directly see the LEDs then increasing the current may make sense. Just be careful about heat and retina damage. You'll need a different driver though. This is such a driver, which will drive the LEDs at 670mA. You'll need a minimum of 10 LEDs in series for this one to work, which will be roughly 30W and more than 2500 lumens. Non-dimmable too.
Good luck!
If you use the thick U-channel that I suggest rather than the thin channel available at Home Depot the lights should be OK heat wise. 3-foot increments, and 10 lights in a row? That is 27 feet. One heck of a mantlepiece. I would say 12 inch spacing would be OK as well. If the lights are pointed up rather than mounted below the mantelpiece, then even less would be OK since the heat will be removed more efficiently.