DIY Veg Light Build

After looking around and reading for a while I decided to build my own LED Veg light. I wanted to follow a couple design goals:
1 - Modular - if something breaks/burns out I need it easy to tear down and replace
2 - Cool/Silent - after having a hard time controlling the heat in my 250HPS grow space these are high priorities, plus it seems all the commercial offerings still have a bunch of fans
3 - Economical/Cheap - this is a learning experience and once I get a better idea I can upgrade components for future iterations
4 - Simple - I try to live by the KISS principle, the less complexity/parts the better

I am no expert so please comment/criticize. If there is a better way to do something that also follows the design goals please tell me. I kind of view this as a group effort that everyone can learn from.

Parts:
Leds - these are the ones off ebay from various sellers you can search "3W 660nm" or something similar and find the sellers. Many sellers are willing to cut a deal if you buy larger quantities, it doesn't hurt to ask. I have a healthy mix of 460nm, 630nm, 660nm, 3000k, and 6000k leds coming.

PCB - rather than messing with a bunch of soldering I'm going to reflow the leds to pcbs then mount the pcbs to the heatsink. This also follows the modularity goal, if I want a different color combo it only takes a couple screws to change it out. I have some 7-led mounts on order but I had some 3-led ones from a previous project. Again check ebay.

Heatsink - if I want silent then I need a lot of thermal mass/surface area to dissipate heat. A 9W (3x3W) led light has a 60gram heatsink so I thought this was a good estimate for the size of my needed heatsink. I need something around 720grams so I went to Goodwill and found a large aluminum steam basket for $3. Following design goal 3, I bought it.

Drivers/Power - use a constant current LED driver, you don't have to mess with running different voltages for different colors. Find the wattage you need and run everything in series. I got a 75v@680ma off ebay for $15 shipped. I have a similar 40v@680ma on its way also.

Lens - I did order a couple different angles of lens to play around with but I don't know if the reduction in lumens (upto 15%) is made up by the increased focus.

The Layout
My thought was to make each 3-led PCB a different focus. For example two 460nm blues and a 6000k would be more vegging while a 660nm, 630nm and 3000k combo would be more flowering. There will be various combinations in the PCB that will allow for different ratios in the whole light.

The Build
I will be running 36x3w leds with an estimated power draw of 78watts. I'll be sure to confirm this will a kill-a-watt when its built.
I'm still waiting on most of the parts to show. I did layout the PCBs on the heatsink, each one is attached by 2 screws. After I solder the leds on I will place thermal paste between the PCB and heatsink.

I'll keep you all updated when all the parts arrive.

Cool Chris, thanx for sharing this. I love the steam bucket idea. I was thinking if I ever build a panel I was going to use 3 or 4 aluminum cafeteria trays so it's nice to see I'm not the only one thinking differently in the housewares section . And I love, love, love that you're going to build some modularity into it so you can swap LEDs in and out. I was always jealous of the T5 gang's ability to play with spectrum's and outputs. Good Luck with this and totally subbed!

Some of my leds arrived today and I couldn't resist building some of my modules. I got my 660nm, 2700-3500k (warm white), and 6000-7000k (pure white). I'm still waiting on my 460nm and 630nm. I reflowed 3 of the flowering modules:
3x660nm
1x630nm + 2x660nm
1xwarm white + 2x660nm

When I get the remaining colors I plan on adding several more flowering modules:
3x630nm
2x630nm + 1x660nm
1x630nm + 1xwarm white + 1x630nm

I'm trying to build almost every 3x combination of my various colors. I only have enough drivers to run 12 3x modules so here is a rough idea of my layout. The green circles are the veg and orange are the flower. In reality I will be running them at the same time but I wanted the ability to adjust the veg and flower spectrums independently.


The reflow worked great and this is what I got. You can see the 630nm and warm white seem brighter which is to be expected since they are more in the visible spectrum.


I'm going to run them for ~100hours straight to test/burn them in. After 2hours my "heatsink" is still cool the the touch.

I was a little disappointed that my lenses will not all fit on the modules. I can only get one lens per module. Its a tight fit but I think I can sand one edge and fit all three lenses on a module.

I used the hotplate method to reflow. The cheap leds are part of the learning curve. Once I get everything hammered out I'll do higher quality parts. I would love to see some Cree v chinese led comparison grows. I suspect there wouldn't be huge differences with similar wattages, but I dont know much.

Does anyone know about protecting the lines? I destroyed a couple leds by over driving them. Should I be using fuses or something? Also what the best method of reducing current or dimming my lights? I've been reading about PWM but does that reduce the led's life?

Hey man, heat sinks aren't measured in grams of material, It is surface area that counts.. as well as thermal conductivity ofc course, aluminium is the cheapest heat sink material you can get..
Search knna's thread for more info on diy leds

Got more supplies and made a couple more modules. Been running the blue dominant modules for ~8 hours and the heatsink is ~95 degrees. If/when I add some thermal grease it should only get better. The unit is bright and with these 4 modules I'm running ~30W. I've got:
1 warm white
2 pure white
6 460nm blue
1 630nm red
2 660nm red

The main point is the ability to switch things around so I can start some experimentation. I added a couple 60degree lens to see what they did. I got my second led driver and a couple more leds to play with.

^^^ schweeeeet!! +rep

I hung it up and hope to test it out a bit. I'm already mid-grow under an HPS and I'm moving in a month so I didn't want to sprout any new seeds. I started a couple cherry tomatoes, from what I understand they act very similar to cannabis. The little guys already spouted in a window seal and its the first day under the light. I moved it a little closer than in the pic, they are ~12" from the diodes. I removed the lenses for the time being. I need to add some thermal grease between the heatsink and PCB, Ill do it when I add a couple more modules with the new driver thats on it's way.

Driver:
I finally decided to stop messing with cheap chinese drivers and get something real. I ordered a 150W Phillips dimmable constant current driver. http://www.futureelectronics.com/en...les/Pages/5804737-LEDINTA0700C210DN.aspx?IM=0 It outputs 60-210VDC with a dimming range of 70-700ma.

Leds:
I added a couple more modules so there is a total of 30x3w led and 2x5w leds all running in series. I had the extra 5w leds from a flashlight project (white cree and 630nm chinese red). The total drop should be ~93v so it pulls ~65w at full power.

Construction:
I added the thermal paste and have noticed the heatsink getting quite a bit hotter. I assume the heat was being trapped in the PCB before. The pics show at full power and 10% power.

To Do:
I need a little better thermal management if I'm going to be running at full power. I also need to add a potimeter to fine tune the current amount.

Conclusion:
Learned a lot and looking forward to testing this guy out. I will probably use better leds on future builds, but I kept the whole project under $120.

Your construction is beautiful!

You can obv. add a fan in it. Any reason you´ve been avoiding it?

I really like the holy pot you´re using.

I just didn't want to mess with a fan. I figure I can adjust the current until heat becomes a problem, plus at lower current the leds are more efficient. If I really wanted to push it I would do water cooling to max efficiency and min sound. I think I can use the pot as a air scrubber also, get a 2 for 1 use out of it.