The DIY COB Addiction

Skybound said:
I'm on the 'fake it till ya make it' path and am a recent HID to LED convert. I swapped out my two 600w HIDs for two 6COB Vero29D builds that I now have in bloom and they're doing fantastic. I now wish to swap out my 4 bulb T5 fixture in Veg as it also produces too much heat and the bulbs are near the end of their life, but rather than spend $200 on new T5 bulbs, I'd rather sink my $$ into an LED fixture for Veg. Sadly, almost all of my searches for "Veg LEDs/COBs" returns info for bloom lighting.

Can someone recommend a good kit or panel for a 2'x4' space? I actually need less light, as I only usually have 2 plants growing at a time (not counting clones), but clones I don't want to receive direct lighting anyways. I also am aiming for something in the 100 watt range. Is it as simple as a heatsink with a 5000k-6500k COB chip and a small driver, or are there other setups that are geared for maximum veg growth?

TYIA!
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Forgot about quantum boards from horticulture lighting group. They offer a few different kind personally the 4K board kills it in veg and bloom but the 5k is perfect for your application.
 
FutRfarmer said:
Hello experienced growers!!!!

I'm getting ready to build my first rig for my first Grow. Heres what I'm thinking. Keep in mind I'm going for quality not quantity. I will be running Doc's gear and of coarse rotating through flower.
I'm going to grab all my lights from timber, I'm planning on running a 320 Watt Quantum Board Grow Light Kit down the center and a 300 Watt Cree CXB3590 (4) COB Grow Light Kit on each side. could use some help with color. I'm thinking 3000k or 4000k on the QB. and for each 4 cob set up 1)3500k 2)3000k 3)3500k 4) 3000k. That's for flowering a 5x5(over powered but I figure I can turn them down as the girls need.

I know there is no magic light, I'm just looking for some help from experience.

For veg, I'm thinking a 240 watt 4000k QB
or cob set up with a mix of 5000k and 6500k.
veg tent will be a 3x3 with half set up for seedlings.
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You would be better off building you own frame with your boards for the center. I can help. Make your boards 3k in the middle. I would change your chip setup to 5k 3k. That way, your plants are still getting the blue and if you screw up and run out of cash like we all do, you can peel the 5k's out for your veg room.
 
I meant to keep ranting but got sidetracked. You know.. go to the river and look at girls in bikini's. We can get you 312 boards with the newest samsungs. No. this is not an add 420. They run at 36v and I got them for my 9 panel. Should be twelve but I digress. So.. I got a 480 running 6 at 80 watts if it worked. For some reason it's maxing out at 370. Still getting 1000 micromules at 16" which sucks. Boards are not working for me when it comes to heat. I do know how to get heatsinks for them. If you look me up in bucks page you can find them. So a 480 runs 6 and a 240 can do the other 3. My point is. 240 1400 for the middle 3. four chips on another 240 and the other four on well... 240. Shit.. your going cree. Gotta rethink my math now.
 
Plus a lot of people make it confusing. Yes 1.4a, that's what they say. That is most times correct, but it depends on board, chip and all other things. Do not let people stray you on a number. I got 14's and 17.5's running fine and my 480 is a 17.5. My point is, it starts to get expensive when you try to put every chip at 1400 milliamps especially when we are changing chips and boards and all kinds of crap.
 
Fsanti1226 said:
Forgot about quantum boards from horticulture lighting group. They offer a few different kind personally the 4K board kills it in veg and bloom but the 5k is perfect for your application.
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If I were doing it now I would do a QB. A diy kit. --->What Fsanti said.:high-five:

Is it as simple as a heatsink with a 5000k-6500k COB chip and a small driver, or are there other setups that are geared for maximum veg growth?
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i do think it has become that simple, i dunno.

Site sponsor Timber grow light has some quantum/COB kits and ready made fixtures but they might be to big for your needs.

for a 2x4 veg and clones, hmmmm.
If it were me I would look for a kit probably at a minimum a single QB288 V2 with Samsung 301B diodes, It might be a bit much light for your clones tho, i dunno. But it would cover your area for years to come.
...... i would want a dimable driver but that is me.

Look for quantum board kits, pretty easy diy. And they do what they do well. :goodluck:
 
I got a little HLG65 quant board for $100 and gives me the footprint I wanted, and with 4k temp, I'm content that they get the blues and some reds. The 65 is a plug and play (kit?). IDK, I guess they used to be kits, but not anymore. Thanks for the tips!
 
yea, but are the fruits as big on the QBs as the COBS?

I want to see some beer can sized colas from the QBs.
 
IDK about others, but I'm using the QB for Veg. The COBs are kicking ass in bloom though and are vastly out-performing my 600w HPS while using less watts and making way less heat. The fuller spectrum has greatly increased resin production and it seems they're finishing about a week sooner than the HIDs.
 
I bought the 3000K 90CRI COB and heat sinks from RapidLED and built my fixture. It works! The driver must put out over 150V. Beautiful light! Thanks Jimmyclone :)

I put the COB on 16" centres (3-2-3) with 1" x 1" x 1/8" aluminum angle. I think this has better uniformity in a 4x4. Not sure if I want to use the reflectors...

I was proud of myself for using less aluminum than jimmyclone...and as soon as I turned it on I saw that the frame acts as a heat sink too. More mass is better.

It pulls 552W at the wall, which is about 520W of light (rated 94% efficiency). it raises room temp by 30F in 20 minutes and tops out at 134F! Luckily I have a 5000 BTu A/C to manage temp.

I'm skeptical that 330W LED is equivalent to 1000W HPS. Growers are using 550W quantum boards in a 4x4 without issues. I just don't have an SQ420 to measure PPFD. Does anyone have numbers? What is the PPF of the Vero D 3000K 90CRI at 1750 mA?

fwiw, the A drivers are a pita to dim. jimmyclone's dimming setup is much more convenient if you plan on varying output often. It's just some soldering.
 
IDK how your COBs are raising your ambient temps by 30º? I have 6 COBs (Vero29/80CRI/D) with passive pin heat sinks driven from HLG-480H-C2100B and at most raises my temps in a vented, but sealed room by 10ºF.
 
Skybound said:
IDK how your COBs are raising your ambient temps by 30º? I have 6 COBs (Vero29/80CRI/D) with passive pin heat sinks driven from HLG-480H-C2100B and at most raises my temps in a vented, but sealed room by 10ºF.
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I should have been clear. There are no plants in the room atm...just testing. I put it in a sealed room to see how quickly temps would rise between exhaust events...and to calculate total BTu/hr to size the A/C. I'm figuring 150 BTu/hr. Although I had to open the door to read the thermometer every minute. Maybe I'll measure temp rise with a 600 W HPS to compare.

I'm using basically the same setup as jimmyclone. It puts out decent heat. I'll know soon enough how the room operates with plants.

I'm aiming for slow temp swings. Now I know things can go wrong in 20 minutes if the A/C and the exhaust fan stop working with lights on. A thermal cutoff switch would be peace of mind, or some auto dimming feature like the Gavita controller.

fwiw, I found some flux numbers on the 3000K Vero D from CCCmints on riu. I should have at least 1270 J/s at *full power*...which gives 882 PPFD in my 1.44 m^2 room. Not sure how jimmyclone is flowering under 450-550 PPFD?
 
Dayyum BoBrown, did you need to use the panoramic feature to get that whole shot into one photo? That is one major cola! My OG Kush isn't stacking up that well, but she sure is getting fatter none the less and it seems they finish almost a week sooner than when under the HPS. I want to try some of those far red boards to put them to sleep. I read that speeds up the finish as well. I'm definitely loving these COBs though, over my HPS.

@Crysmatic, you're light years ahead of my regarding understanding the science of light measurement. You can control your lights and your vents with an Arduino or Pi, and I could probably help you with code and maybe circuit planning if you want to build something like that. I still have to read up on the OpenAG tip you left me in my journal, but I'm pretty sure they've done what I've been trying to do.
 
Thanks for the offer Skybound. I'm strictly KISS in my hobby. Commercial is another thing altogether ;) I hope you sort out your issues. It's nice when things work the way we want them.

The light is bright! The plants were suffering so I switched to a 600W HPS on 75% power. They were getting 57 moles of light in 18 hrs :O I really wish I had wired in a dimmer...or just go 11 hrs with some sativas from seed.
 
I got some more questions. I'm considering hacking my 6x vero29 fixtures and thinning them down to 4 COBs per fixture and use the 2 deducted COBs from each to build a 3rd fixture. Currently, my fixtures are driven by HLG480s and I mostly wanted to know is if this driver will be able to drive only 4 of the Veros without burning them out or do I need to leave those fixture as is (6x) to protect the COBs from too much voltage/current. Real quick, the forward voltage of the Vero29D is 38.7 volts, so 4 of them is 154.8 volts and my very limited understanding is telling me that this is within the output range of my driver. Am I wrong?

A side concern about doing this is that as it is now, the highest I can run the cobs is about 70% of the total output. So I was thinking I could reconfigure less lights and drive them a little harder (I've read Vero29's like to be driven hard). If I get above 70-75%, my plants foxtail and leaves burn, so I'm guessing I could spread out the light more in my 3'6" squared space and get a better response from the plant. FWIW, plant response is THEE most important priority here, I'm just looking to get a little more bang for my buck and I need to build a 3rd fixture for a 3rd bloom room of the same dimensions. So, in your opinion(s), can I get away with harvesting 2 of the 6 COBs from each of my fixtures and just buy a 3rd driver to run the next 4?
HLG480.jpg
Kush.JPG Just a little tric porn of this OG Kush, bloomed for 66 days plus an added 7 to transition. It looks to be a happy amount of ambers, but I prefer them mostly cloudy.
 
Skybound said:
I'm considering hacking my 6x vero29 fixtures and thinning them down to 4 COBs per fixture and use the 2 deducted COBs from each to build a 3rd fixture. Currently, my fixtures are driven by HLG480s and I mostly wanted to know is if this driver will be able to drive only 4 of the Veros without burning them out or do I need to leave those fixture as is (6x) to protect the COBs from too much voltage/current. Real quick, the forward voltage of the Vero29D is 38.7 volts, so 4 of them is 154.8 volts and my very limited understanding is telling me that this is within the output range of my driver. Am I wrong?
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There are pros and cons to your solution.

I figure your current fixture puts out 800-850 PPF at 70-75% power. The four Vero D at 2100mA will put out about 760 PPF....so you'll be down 5-10% light. It's a 325W light vs a more efficient 350W light. The extra yield pays for a new six COB light with a single harvest. It depends what you value more.

The HLG320H-C2100B puts out 156V max...absolutely perfect for four Vero D. But I hear you on buying new drivers, and having the old ones sitting around on a shelf. Mouser won't take my practically BNIB A drivers back to exchange for B drivers...so I'm sticking with what I have.

You just won't be using all of the driver's power. In that sense, the hlg320 is a better value driver for what you're doing because it's cheaper than a 480, and cheaper per Watt. You may want a 480 for a big light down the road?

The hlg480 puts out 280V max...so the COB will see up to 70V forward voltage. Wire it up and test max voltage. Bridgelux gives max current, and max reverse voltage (-65V), but no max forward current. Does anyone know?

Current will kill the COB before a little extra voltage. You're still in the constant current region (so it will stay at 2100mA). I'd say the COB should handle at least 65V forward...can't say how much more.

jimmy stressed running the LED at one step below rated current (going 1750 mA instead of 2100mA) for the sake of life.

While the charts say you get 20% more light going from 1750mA to 2100mA, the inevitable higher temps will cost several percent efficacy. With fewer COB you also lose some light uniformity. Stronger lights held higher up improves vertical light uniformity.

Geometrically you want the COB on 21" centres in your 42" square room...but I'd use 22" to account for wall losses.
 
Crysmatic said:
There are pros and cons to your solution.

I figure your current fixture puts out 800-850 PPF at 70-75% power. The four Vero D at 2100mA will put out about 760 PPF....so you'll be down 5-10% light. It's a 325W light vs a more efficient 350W light. The extra yield pays for a new six COB light with a single harvest. It depends what you value more.

The HLG320H-C2100B puts out 156V max...absolutely perfect for four Vero D. But I hear you on buying new drivers, and having the old ones sitting around on a shelf. Mouser won't take my practically BNIB A drivers back to exchange for B drivers...so I'm sticking with what I have.

Geometrically you want the COB on 21" centres in your 42" square room...but I'd use 22" to account for wall losses.
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Due to exigent circumstances, I have a suicidally tight budget and need to cut every corner I can. Subdividing my 12 COBs into groups of 4 would help me to accumulate another fixture for only the cost of a driver and potentiometer. A new 320H/2100 would be perfect, assuming that leaving 4 COBs alone with the 480H/2100 is safe and the 5-10% loss of light doesn't kill my yield which is in the 1 pound range per harvest.

My current fixtures have the COBs on 12" centers which is obviously way too close so I'll be looking to hack my frame apart and rebuild anyways.
 
I have a 65w Quantum Board 4000k in veg and I notice the growth has slowed from when I used a 100w of T5. I've read many people having good results with the 4000k, that's why I got it, but I'm not seeing any performance and actually see it as a loss. Should I have gotten a 5000k or 6500k board instead?
 
Skybound said:
I have a 65w Quantum Board 4000k in veg and I notice the growth has slowed from when I used a 100w of T5. I've read many people having good results with the 4000k, that's why I got it, but I'm not seeing any performance and actually see it as a loss. Should I have gotten a 5000k or 6500k board instead?
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It has nothing to do with CCT, my guess is that you have the board too far away or power it too low, what driver are you using?
 
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