Help me build an awesome LED!!!

[GeorgeWBush]

Hi. Due to my circumstances it looks like LED is ideal for me. The problem is I don't have $1000 plus to purchase one. I hear I can build one for a fraction of the cost, and that it will be better than anything I could buy.

That sounds perfect! I'm more than willing to put in the time and effort, but I don't really know where to begin.

Say I wanted to build a 300 watt LED for my flower room. What would a ballpark figure be for a price tag? How about a 150?

What do I need? What are the best LED's and where can I get them for the best price?

I'm willing to document my journey but I have no idea where to begin. Could someone point me in the right direction? I'll read whatever is important. I'll build whatever is necessary. I need it to be safe. I need it to be stealth. Most important, I need it to grow great pot. Any suggestions are very welcome.

 

[sm0k4]

Well for my 300 Watt array, I almost figure on spending $700 when its all done. Maybe more. I already have $300 into it just in LEDs. Still need heat sinks and more driver ICs.

Its still not cheap to build it right. The only cheap way to do it is buy cheap LEDs at $1 a pop. The good LEDs are $4-$6 a pop. The reason for building our own though is to get away from the cheap LEDs the commercial lights mainly use. So it will cost a LITTLE less(not a fraction like you think), but it will be higher quality for growing.

You may want to start here and here. There is decent info on the subject. Designing a light can be a lot of work, so depending on what you want, it could be easy or hard. If you have no knowledge of electonics or diode circuits in general, then you will struggle until you grasp the knowledge on the circuit.

One step leads to the other. You don't know what size driver you need until you know how many LEDs you want to run in one string and what power you want to draw. You need to design it so that you aren't constantly picking new parts out because your string changed. Get your layout finalized FIRST, then go from there. Keep things as balanced as you can. Equal number of LEDs per string, equal Voltages on parallel strings, etc. You must also watch out for uncommon string voltages. Get a good idea what the common driver voltages are and try to get your strings close to that voltage rather than redesigning the layout because you can't find a driver with 56 Volts.

Once you get your light designed, THEN you source the drivers, heat sinks, etc. You will make mistakes and you will redesign it a few times until everything lines up and fits together. It just takes time and math. Use excel for spreadsheets and calculations on the fly. Saved me lots of time.

This is all I can think of. Experience is your only friend here. It took me a couple weeks to finalize my light, went through 4-5 redesigns because of parts issues. I never checked common values for components before designing. Had to redesign everything because my string voltage was too high. The best starting place is to see what voltage you want to run the strings at, and try to limit your layout by that.

 

[Mr. Bongjangles]

http://www.icmag.com/ic/showthread.php?t=158792

http://www.icmag.com/ic/showthread.php?t=193689

Couple of threads for ya to check out, both doing the DIY LED thing...

 

[GeorgeWBush]

Thanks for the help and the links. I'll be checking those out.

Out of curiousity... is it possible to use an existing LED with cheap lights and just replace the cheapies with quality led's?

 

[Mr. Bongjangles]

Got me man, but I imagine the power supply wouldn't match up properly. The panel itself could maybe be used, tho it seems different led's need different types of heatsinks, so then again the housing may not be adequate. Best to ignore all this and let someone who has built one answer, but I'll ramble a little in the meantime

 

[sm0k4]

Thanks for the help and the links. I'll be checking those out.

Out of curiousity... is it possible to use an existing LED with cheap lights and just replace the cheapies with quality led's?

As long as the new LED string matches the driver voltage output...or close to the output with an adjustable driver. Once you start swapping things around, new calculations need to happen to account for the varying voltage. All LEDs don't operate on the exact same voltage.

Best advice is to spend a crapload of time reading as much as you can on how LED circuits work. Get some math down and make a spreadsheet. On the PC DIY Build link, there is a spreadsheet I made as a zip file download in the 2nd post. It will help you by calculating the math, you just need to input the info from the component datasheets.

Also, the heatsinks you use will matter. Rather than have you struggle with the calculations for heat sinks, the basic rule of thumb for 1 Watt emitters is 100cm^2 surface area of cooling per LED. You can get away with less if you active cool via fans. With 3W or 5W emitters, you will need more area of cooling.

3W and 5W need to be spread out a bit, so that digs into the irradiance and color diffusion. Now you have fewer sources of light which leads to a less evenly dispersed light and proper mixing of spectra won't happen. You could overcome this by spacing them closer, but that cuts into your grow size then.

So everything affects everything else when designing an LED light. You want all the factors of a good grow light, which takes time and research to accomplish.

From the hard work of KNNA, he came up with 120-130 degree 1 Watt emitters powered at half to three quarters of their max. power, will emit a good diffused light. Plus they are way more efficient.

The problem with 1W emitters is that the height is restricted to 2-3 feet due to lack of penetration. If you go with 3-5W emitters it will take more of them to achieve the same dispersion and diffusion and will also output more heat which will then require a more expensive heat sink.

I opted for 1 watt emitters because it makes more sense to have more sources of dimmer light than less sources of brighter light. Plus I'm not growing too tall and will probably use side lighting strips if I go taller. Proper light diffusion and a balanced wavelength at maximum irradiance are the main goals.

 

[GeorgeWBush]

Thanks Mr Bongjangles for the links.

Smok4, thanks again for your help. You seem like you really know what you're doing.

I thought I would be able to build one for a lot cheaper. It looks like I may have to hold off on this build for now. HID is just much cheaper to start with.

 

[sm0k4]

Thanks Mr Bongjangles for the links.

Smok4, thanks again for your help. You seem like you really know what you're doing.

I thought I would be able to build one for a lot cheaper. It looks like I may have to hold off on this build for now. HID is just much cheaper to start with.

The topic interests me a lot so I keep reading about light and how plants use it. LED is still too expensive to take over the HID market though. Once manufacturing becomes easier and newer tech. comes out, hopefully prices go down.

For small grows with heat and height restrictions....1W LED all the way. I'm liking my growth in veg so far with 27W of LED in my PC case grow. The best thing is not having to fight the ventilation in small spaces without it sounding like a jet engine.

Just take the time to read up and understand most of it, and the rest can be picked up with experience and failures.

 

[budlover123]

Building a light with these high-powered leds isn't cheap, but look at it this way, since the manufacturers don't let you know exactly what you are buying, they usually don't even tell you who made the things, let alone the bin number or possibly even just the output that the leds are rated at, instead they use a scale of HID equivalency that is totally false in my view

It's kind of pathetic the way they always list the wavelengths and nothing else, like they are trying to be like "see, we have technical info, now buy our junk" I believe it is highly likely that they use the lowest quality 1 watt leds they can get their hands on, because why not, most people don't know there is a difference.

It is difficult to design a circuit, I recommend using prebuilt xitanium drivers if you are not an electrician, they have datasheets that will show you ideal circuits to run on them, very easy, check out my HPS supplemental LED light, that's 3 xitanium 700mA 17 watt drivers, 2 circuits of 12 royal blue, each broken up into 2 parallel circuits of 6, and one circuit of 8 white LEDs that is broken up into 2 parallel series of 4 LEDs each.

parallel circuits are simply 2 practically identical circuits joined together at the power source. so it's like you have 8 leds, link up 2 sets of 4 leds, then connect both of them together at the power source, you got your parallel circuits.

I love the corgis on the treadmill gif, that is great