Introduction: 36w LED Grow Light Bar ( OLD )
I'm leaving this instructable up as informational please don't use this though.
I have a new version that uses 3w leds that is better. LINK HERE
The goal of this LED light is to be more efficient and comparable cost to t8 / t5 grow lights.
Lumens / watt: The LED chips used provide 100 lumens per watt compared to t8 (87 lm/watt) and t5(92 lm/watt).
PAR: By providing more light in the Photosynthetically active radiation range we increase efficiency. Because we are providing more light in the PAR range, we can decrease the total amount of light as we aren't wasting a bunch of yellows and greens.
The problem with many LED lights is they are expensive. Since we are DIY we can save lots of the labor / assembly / retail vs a production unit. It also turns out that many of the parts are actually pretty cheap...
because our lights are 1/2 the power of 4' 2 bulb t8 and 1/3 the power of 4' 2bulb t5 user will see this on their energy bill.
Led emitters cost about the same as a t8 / t5 bulb, but their life is 50,000+ hours, over twice the life of a t8/t5 bulb at 10,000 - 20,000 hours.
Step 1: Materials / Tools
1x Blue or Royal blue LED emitter 10w, 900ma (link)
3x Red LED emitter 10w, 900ma (link)
1x LED Driver 30w 900ma (link)
4' 3/4 in aluminum U channel (lowes, homedepot)(8ft cut in half is cheaper per ft)
power cable (scrap or new)
m2 screws (link)
some wire (i use wire with connectors so can swap out leds if they fail, but it's optional)(link)
some thermal paste
circular saw(or other saw)
1.6mm drill bit (see above link)
Step 2: Cut / Measure / Drill Almunium
Measure aluminium 42" (or desired) length
Cut with saw
Measure space for driver / power cable on the end
measure spacing for LED emitters
Mark holes for LED screws
Drill with 1.6mm bit
Tap the holes with m2 tap
Step 3: Attach LEDs + Driver
Put a drop of thermal paste on led bottom
Screw it in hand tight
i'm lazy so i just taped the driver, drill holes and screw it in if you want to do the extra work.
Step 4: Wiring
Series circuit. (voltage adds). Should look like a big loop.
Solder wire (with or without connectors) between LEDs
Splice / Solder / Wrap Led>Driver
Splice / Solder / Wrap Driver>PowerCord
Step 5: Plug It In
I tested it out using peppers, onions, romaine lettuce, and zuchini, all grew just fine under it.
Remember you need 2 fixtures for a 4x2x2 area ( one led bar = one 2bulb t8 fixture).
The temperature of the fixture hovers around 60C (hottest point is at the blue led) when the room temp is 85. Runs much colder if you have a fan running near it or colder temps.