Looking for input on generic Chinese LEDs

[Southwards]

Hello everyone! I am pretty new to the growing scene, so I thougth I'd ask some questions (apologies if this is not the place to do so)

Right now I have a single youngling (ice cool strain, little info online, sativa dominant, 'bout a week old) growing under about 120 real watts of CFLs (I had another seed, but it didn't make it past the seedling stage, I blame helmet-headedness).

My grow area right now is a closed wooden box about 60*70*70 cms big I had from my meat drying days, with big holes at the top and bottom of one of the sides for airflow and a small computer fan hooked up. I will try to get some pictures up when I can, promise!

There are MANY things i want to add to my system, among them:
- I wanna change the aluminum foil it has on all surfaces (I know) with mylar.
- I am gonna get two 220V ac fans and hook them up as an exhaust (creating negative air pressure), with a DIY carbon filter.
- And lastly, and where I have the most doubts, I want to try out LEDs! Because TECHNOLOGY

I have some background in electronics so I think I can pull this off, what I am planning to do is to get an old PC power supply, and use its 12V rail to feed a DC-DC step up converter with current control. One like this:

I will then use the controller to drive however many (3-4?) generic ebay 20W LEDs like the ones they use for floodlights, taking care to use some aluminum angles for dissipators and such. 20 watts is the minimum as 10 Watt ones only take 9-12 volts.

Is this at all feasible? Am i missing something? Do i go cold white or warm white? There appears to be RGB models at a premium, are they worth it? Am I a total dum-dum?

I also have 2 friends with more experience in growing than I that have been helping me out and I'd like to repay them by helping them build their own LED systems. So I think of this as a prototype of sorts.

I think that is all (for now ), any tips are welcome!

 

[Southwards]

I forgot to mention, cost is of course, a huge factor in all this. But I also am a tinker at heart, so the process definitely has entertainment goals.

These are the LEDs I meant:

 

[GrowrLvlNoob]

Do you plan on using led for bloom as well? If so you might want to add some blue and red ones. I believe those are the color wavelength's the plants prefer I'm bloom. I would check some schematics for other led wafers to see their spread and try to mimic that. Best of luck to you and happy harvest

 

[Southwards]

Yes, I was planning on using them on all stages, I still haven't figured it out, but it seems there is some way to hook up those kinds of LEDs that allows RGB. I think it involves more expensive LEDs plus extra circuitry tho. I will have to give that subject another go.

 

[GrowrLvlNoob]

There are a few diy led setups I have seen while researching led lights. Check some of these guys journals who primarily use LED they know what's up and can dial you in on exact wavelength's so you don't buy the wrong stuff

 

[Dwight Monk]

I would think the size of your box will make it difficult to get very big plants in anyway (as think that converted to a little over 2 feet all directions). I got a used cabinet and tried to make my own, as I had bought one pre-made but it was limited in size (see if i can convert it right 20cmx35cmx91cm tall), ended up making two as cabinet I bought was too tall so cut it in half and added a top to part missing a side after cutting. They are 35cmx53cmx121cm tall and one is 182cm tall. So the lights were the biggest expense for me, as computer fans and a 12volt adapter and some hardware and caulking to seal it up didn't cost that much. I used those reflective windshield sun screens, not perfect but better than foil and that mylar stuff is expensive (also hear flat white paint reflects as good or better depending on who you ask).
My boxes (one I bought premade the little black one, and other two the ones I built):

 

[Southwards]

So I've looked into it a bit and it seems there are indeed red and blue ones in the same form factor:
1W 3W 5W 10W 20W 30W 50W 100W Deep Red LED Plant Grow Growth Light Lamp 660nm | eBay
Even though they cost a bit more the main drawback i see with mixing it up is that they operate at a different voltage so I would need to have each color on a different boost converter. Could still be worth it but don't know what improvement to expect.
The red ones come in 620 and 660 nms while the white ones come in either hot or cold (same kelvin scale as CFLs I believe). Suggestions?
Also reading journals as we speak

 

[Southwards]

Very discreet looking urbanmonk, i like it! The plan is to eventually (next season or so) devote this smaller enclosure just to mothers and to build a bigger one for harvesting. I will take a look at your journal for sure!

 

[Dwight Monk]

Very discreet looking urbanmonk, i like it! The plan is to eventually (next season or so) devote this smaller enclosure just to mothers and to build a bigger one for harvesting. I will take a look at your journal for sure!

I forgot about the carbon filter stuff that comes in a roll (it's pretty cheap online), it's made so you can cut to fit for furnace filters and air fresheners, seems to cut back the smell w/o impeding the airflow in or out of the computer fans. And the fans run quiet and don't draw a lot as 12volts, the adapters easy to come by at thrift store cheap (one I had a very old router, and power cord for it put out what was needed for volts so it didn't cost me anything, sometimes saving everything has advantages though rest of the time you just have too much junk around LOL)
So major cost was the LED lights, and they not the latest technology so they were right around $100USD each, but one for each box so just one would have worked for me for awhile.

 

[Islandgrow]

On youtube check growmau5 I think his name is he has a series of vids on building led systems. That should answer any questions you have pertaining to led .

"carpe diem"

 

[VladimirPutin]

you could get the cheap ones, they will work.

or you could get the expensive ones, they will work even better

 

[Southwards]

First of all, sorry to the mod that had to do clean up on those links, won't do that anymore!

Thanks for the info Island grow!, I combed through his vids and I think he mostly uses Crees right? Which leads me right to Vlad's (can i call you Vlad?) suggestion which are also Crees. After a quick look at the price ranges w/ shipping for 3050s (which i believe i read somewhere are good choices) I found out they are about 35 USD for a single 90w chip, does that sound about right? Tempting but I... I don't think I am ready for that kind of commitment just now, sadly.

I am a novice grower (and a broke student) and would prefer to keep upfront costs low. I am anticipating a certain amount of mishaps for this particular project mostly due to my own ignorance (learning general growing techniques like LST and SCROG). Crees do seem like excellent choices, and i will keep looking into them but I don't think now is the time, maybe next gen.

Some of the advantages I see in the setup I had in my mind is that even if some LEDs do die out early I can order more than I strictly need since costs are so low and it will be spread out among a few persons. They come out pretty cheap per watt used and are still LEDs so should be reasonably efficient. I can get aluminum in bulk. And I get to toy with step up converters and disassembled PC power supplies

Before you all go away tho, what is it that is bad about those kinds of LEDs? reliability? spectrum?
Can I ask what you consider a good spectrum composition would be for veg/flower? I was looking into Blue+Red+White so 3 drivers in total.
I have seen the following wavelengths offered, what would be a good combination? :
Warm white 3000-3500K
Pure White 6000-6500K
Cool White 10000-14000K or 16000-20000K
Red 620nm
Red 660nm
"Royal Blue"
Blue 450-460nm
also green amber and yellow are available on some places.

gotta keep on learning...

 

[Southwards]

I mean look at this, I am so hyped I already have a mockup for foolproof converter calibration instructions.

DC converter initial calibration steps:
1st with the converter turned off hook up DC converter input with nothing connected to output
2nd Set both knobs to an extreme, clockwise or counterclockwise doesn't matter
3rd Put your multimeter in DC Voltage mode at 200V
4th Switch converter on, measure the output voltage, move one of the knobs all the way back and forth to find out which one changes the voltage. (After this step which knob controls voltage and in what direction it increases should be known, repeat steps 1 - 4 if there are any doubts.)
5th Turn the converter off, go ahead and label the voltage knob with a V and a + sign in the direction it increases, label the other knob with an A for current. Lastly label the output terminals of the converter as + and - accordingly.
5th Now you want to see in which way current increases! Turn the converter on again and measure voltage as you just did, turn the V knob as far down as it goes (it should go to about 13V if you are using a 12 V power supply).
6th Power off the converter and disconnect your multimeter and set it to measure DC current 10A (DCA), you will need to disconnect the red lead on the multimeter and connect it to the space that says 10A to measure this current.
7th Connect the + output of the converter with one end of the provided power resistor. Then connect the red multimeter lead to the remaining resistor end and the black multimeter lead to the - output of the converter.
8th Switch the converter on. The multimeter should be measuring current now, turn the A knob all the way from one end to the other to find out in which direction it increases. Once it is found, power off the converter, and then disconnect the multimeter and resistor from the output before it gets too hot
9th Label the increasing direction of the A knob with a +, you should now know which knob is which and in what directions they increase

Actual LED hook up (Make sure to repeat this tutorial any time you make changes to your lighting or a LED gets significantly beat up (dead spots an so on))
1st with the converter off, turn the Voltage all the way up and the current all the way down.
2nd Connect the LEDS in parallel to the output of the converter (figure?), take care with the polarity and also put the multimeter in a current measuring configuration. MAKE SURE YOU ONLY CONNECT ONE TYPE OF LEDs TO EACH CONVERTER OTHERWISE THEY WILL DIE VERY SOON
3rd Switch the converter on. SLOWLY turn the A knob up untill the LEDs lights up, keep going slowly until you hit the goal current then stop (goal current equals suggested current for the type of LED*Number of LED units)
4th As an extra security measure, with the present configuration, slowly turn the voltage knob down until any further turning of the V knob would affect the current measurement. Leave it there.
5th Power off. Disconnect multimeter and close circuit with LEDs only. Power on, everything should work just as it did before. Congratz!

 

[Islandgrow]

First of all, sorry to the mod that had to do clean up on those links, won't do that anymore!

Thanks for the info Island grow!, I combed through his vids and I think he mostly uses Crees right? Which leads me right to Vlad's (can i call you Vlad?) suggestion which are also Crees. After a quick look at the price ranges w/ shipping for 3050s (which i believe i read somewhere are good choices) I found out they are about 35 USD for a single 90w chip, does that sound about right? Tempting but I... I don't think I am ready for that kind of commitment just now, sadly.

I am a novice grower (and a broke student) and would prefer to keep upfront costs low. I am anticipating a certain amount of mishaps for this particular project mostly due to my own ignorance (learning general growing techniques like LST and SCROG). Crees do seem like excellent choices, and i will keep looking into them but I don't think now is the time, maybe next gen.

Some of the advantages I see in the setup I had in my mind is that even if some LEDs do die out early I can order more than I strictly need since costs are so low and it will be spread out among a few persons. They come out pretty cheap per watt used and are still LEDs so should be reasonably efficient. I can get aluminum in bulk. And I get to toy with step up converters and disassembled PC power supplies

Before you all go away tho, what is it that is bad about those kinds of LEDs? reliability? spectrum?
Can I ask what you consider a good spectrum composition would be for veg/flower? I was looking into Blue+Red+White so 3 drivers in total.
I have seen the following wavelengths offered, what would be a good combination? :
Warm white 3000-3500K
Pure White 6000-6500K
Cool White 10000-14000K or 16000-20000K
Red 620nm
Red 660nm
"Royal Blue"
Blue 450-460nm
also green amber and yellow are available on some places.

gotta keep on learning...

He does use crees but check citizen cobs or bridgelux I read that when driven at higher voltage their efficiency is better than crees . And they cost less and no holder needed. Just what I picked up so far.

"carpe diem"

 

[Southwards]

He does use crees but check citizen cobs or bridgelux I read that when driven at higher voltage their efficiency is better than crees . And they cost less and no holder needed. Just what I picked up so far.

... That is actually an excellent suggestion it seems! I have checked citizen cobs so far and here is what I found:
1 An actual honest-to-goodness datasheet, I actually know what I am getting.
2 They can be driven with the same setup I had in mind.
3 They include a "protection device" in parallel with the LED.
4 They seem to be full spectrum, actually I don't know if that's correct, at least they output light in a wide range of frequencies.
5 The lower bin ones come out to about 10 bucks per max 117 Watt unit /w free shipping.

Should i pair them up with red or blue?

Thanks again for suggesting this! I think I am definitely getting some of these

 

[Islandgrow]

... That is actually an excellent suggestion it seems! I have checked citizen cobs so far and here is what I found:
1 An actual honest-to-goodness datasheet, I actually know what I am getting.
2 They can be driven with the same setup I had in mind.
3 They include a "protection device" in parallel with the LED.
4 They seem to be full spectrum, actually I don't know if that's correct, at least they output light in a wide range of frequencies.
5 The lower bin ones come out to about 10 bucks per max 117 Watt unit /w free shipping.

Should i pair them up with red or blue?

Thanks again for suggesting this! I think I am definitely getting some of these

I am in no way an led pro but have been looking and researching a lot . 3500k or 4000k is a good middle line or if you like you can always put a few 5000k in the mix . But most I see use 4000k I think.

"carpe diem"

 

[Southwards]

Upgrade:
To start, I am still getting some Citizen COB LEDs (CLU048-1212 4000k) as soon as I get my paycheck next week (unless my paradigm is shifted some more (that would be welcome))

To clarify, the listing I saw for the Citizen COBs was wildly overselling the max current you should go for with them, nominal current is 1.08 amps which for a typical voltage of 34.6 comes out to just over 37Watts. You should be able to overdrive them to about 1.8 amps, but that would cut into their service life i would think, they would also probably be less efficient, but maybe someone with more experience can say for sure. (The original seller was technically listing the maximum input current specified in the datasheet, not something you actually want to drive them at tsk tsk)

I also came up with an inflated price for CREEs for two reasons, first I looked in digikey, which seems to overprice COBs in general, second it seems like I was looking at a high end binning or something along those lines. Further searching for CREEs with similar power outputs and about the same calculated efficiency show only a 20-30% price increase with respect to Citizens.

I did some marginal searching on Veros, they are about the same as the others, also they hired a better graphic designer for their datasheets.

Currently it seems to me the COB market is pretty competitive then. This is a good thing! To anyone seriously considering cheap chinese no brands like I was, I recommend you look a bit more into COBs, there are some real bargains out there. Thanks to Vlad and IslandGrow for pointing me in the right direction.

To add my two cents now as to what COB to buy, I would say this: As far as I can tell from some basic datasheet comparissons, a lot of the higher binning scheme is hype, and it preys on people's "gotta have the very best" mentality.
Don't get me wrong now, better binnings DO seem to increase efficiency quite a bit depending on the manufacturer, but if you asked me wether that justified as big a price premium as I've seen I would probably say no unless you are a commercial grower (and have done your math) or live off the grid or something. I picked the ones I did because they edge out the others ever so slightly in nominal power and advertised efficiency while being a tad cheaper.

I will keep you updated in case further developments happen