Hi everyone. I just registered (the captcha for this forum is next to impossible) and this is my first post. This thread is inspirational! A friend of a friend has a few Ebay LEDs in a long term testing situation and some AliExpress units on the way. He's tried a few lower power options along the way, here is the steer clear list for newbies.
Don't use a chip with less than 50 diodes on it. Isn't worth the time.
No UFO lights or any LED system with multiple 3W or 5W diodes.
Don't use Ebay power supplies. Should you need the 5 year warranty it will pay for itself buying through a known retailer.
In a small setup the blue will make a difference. The nature of red light is that it needs more power to be effective and the plants receiving the red light should be much larger. The red may be effective for you to experiment with, but power is the name of the game.
These have a 16 diodes, a 4x4 matrix. All the Ebay stuff seem to be about 1W per each diode in the matrix, so 16W each. If you run that at a reduced rate (which you should) you get about 11W each x 4 = 44W for blue and 11W x 6 = 66W for red.
11W was chosen as an arbitrary number, anything between 44W and 64W will work (16 x 4 = 64W) for the blue. You have a few options for power bricks. 3.5V * 4 = 14V needed to power the blue, so this one might work if the math is right.
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2122984_-1
If you get that then you'll run 4 blue chips + - + - + - + -, the red line from the brick will hook to the + and the black line will go to the -
You could also get individual 10W bricks for each of them.
Those will all need a heat sink, but not a fan if they are not in an enclosed space. Also worth noting, 4 of those red lights would make great brake lights for an automobile
For big power monochrome LEDs there are 50W (10x5 matrix) 440nm and 560nm Ebay units that work well. It looks like the 100W (10x10) units are also out. The friend of mine will be trying a 10x10 450nm "royal blue" with the slightly higher voltage version of the Ganjatica's power supply the LPC-60-1400, and an 80mm heat sink and fan. Driving down costs per unit is important.
Here is something that should be discussed by DIYers.
http://www.ebay.com/itm/1-PC-150w-200w-300w-500w-Bridgelux-45mil-High-Power-Led-COB-Chip-White-Blue-UV-/201180380514?pt=Lamps_US&var=&hash=item2ed748fd62
http://www.ebay.com/itm/2pcs-500W-Pure-White-Superbright-LED-Light-Lamps-For-DIY-506Watt-Chip-6000-6500K-/271736862137?pt=LH_DefaultDomain_0&hash=item3f44c775b9
The power bricks are out there too. Does Cree make anything like this?
The plywood is a great idea r8rfan! Looks like you've got room for a lot more if you need it. The way it is mounted looks very effective too! How close do you keep it to the top of your garden?