I wanted a led light that was cheap and would perform the same as or better than t8 / t5 fluorescent lights.

In this instructable i make a 50w led bar to replace a 4' 2 tube fixture

The cost is around 23$.

Step 1: Tools & Materials

Tools

soldering iron

saw

(optional multimeter for testing)

(optional 2 aa batteries for testing)

Materials 23$

18 - 21 pieces - 3w LED with star heatsink (ebay)

led driver 600mA 36-60v (ebay Constant Current Driver for 12-18pcs 3W High Power)

2 prong power cord (ebay)

thermal adhesive (ebay)

~4.50$ 42in of aluminum U channel(i bought 8' and cut in half) (lowes, home depot)

.50$ solder

1$ 8' of 20-16 gauge wire

1$ electrical tape

LED Selection:

I picked a 2 red : 1 cool white ratio.
Red has been shown to be most important and its possible to grow plants with only red light(although there are some problems). To reduce strain on the plant we give it most of the other wavelengths in small amount (from the white) and we pick cool white to give it more blue. We need about 12% blue light. With cool white being almost 50% blue light we get around 15%. I go 1 red (620nm) 1 far red(660nm) to get the most optimal light for the different photosynthesis peaks. White is easier on the eyes and provides all the other wavelengths in smaller amounts so i think its better than going just only red and blue.

Although going red and blue is possible. If you want to do that go like 5 red : 1 royal blue.

Also if you don't want to deal with wavelengths you can just go 100% white that's fine.

leds need to all be the same mA, voltage can be different.