Old Skool... But Wanna Learn about COB LED

Hello LED Crew,

A friend completed their first few led grows with 2 cheap 200w chinese pink colored led panels.

Yielded about a 35g/light. Quality was good, but not as dense or large as preferred.


I have seen talk on the boards about these COB leds.


Seems there are many different brands/models of chips???



Everyone would love to try them out they just want to understand what they are getting into.


How do you compare 2 chips/boards? What types of ratings should I look for.


Are the premade chinese models any good or should I go DIY?



I would guess I need chips and some sort of ballast/power source?


Last thing, what's your dream LED fixture? (how many watts COB, multi spectrum, shape, cooling ect.)



I don't think we have made it yet, but maybe LED's can surpass HPS sometime soon.


Let's make this a place to discuss and share ideas about the future of LED's. If anyone has really great idea let's build it!!!.

My take on the entire matter is, that LED lighting, if understood properly, is capable of producing comparable results of HID sources. That being said, LED has so many variables it can be difficult to quantify the correct setup for any given space which is already in use.

We used to buy the biggest lamp we could afford, and build the room to fit its capability....
Now, we can design, and build the light source to fit any available space.....

HID will always have its advantages, but so will LED.

Chip Green said:

HID will always have its advantages, but so will LED.

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i wont say "always" as the sole advantage of HPS right now is low entry cost, which gets absorbed in 1-2 years with higher operating costs vs. LED

with the way LED prices are falling, efficiency is increasing, and more people are learning how to do well with them, HPS will lose that low entry cost in due time. HPS's last efficiency bump was DE almost a decade ago. LED efficiency is increasing by about 10% per year and costs falling at a rate faster than that

ceccorp said:

A friend completed their first few led grows with 2 cheap 200w chinese pink colored led panels.

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they probably werent 200W each, and the efficiency of them was probably lower than the HPS you were looking to replace. Not really representative of good quality LEDs

So I would like to understand the latest technology. Are COB's the latest and greatest?

Why are some white and some pink/ other colors.

ceccorp said:

So I would like to understand the latest technology. Are COB's the latest and greatest?

Why are some white and some pink/ other colors.

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LEDs are the latest and greatest, and are always improving. there are monochromatic LEDs and "phosphor based" white LEDs, the latter have been popular for a few years now because they offer great results, from 1.2-2.0 GPW depending on setup and strain and grower skill

purples try to target the red and blue "absorbance spectrum' of the plan but early red and blue diodes werent all that efficient.

current leading edge are phosphor-based whites in 2700-3500k and 80-90cri (used alone), and also phosphor based whites augmented with reds which are the 9-pound hammer of photosynthetic energy but have only increased in efficiency to decent levels in the last year or so

People may say "COBs" or "QBs" or "PCBs" or "hard strips" etc, these are all "phosphor-based white" LEDs and basically do the same thing. there have been some commercial fixtures that have offered these white diodes (spectrum king, next light, fluence (augmented with reds), in the end they all do similar things and we know they work and are in the tweaking stage as far as people experimenting with different color temps and CRIs etc.

bottom line is at this point just about ANY phosphor-based white solution should be more efficient than any light you've ever used.*

*one more thing of note -LED efficiency for a given chip can differ dramatically based on how hard you run them. can literally be up to 50% more efficient when run at 20% of its maximum current. people seeing the best results are underdriving their chips to get them to respectable levels. of course youre spending a lot more on chips at this point, but there is a "sweet spot" of about 40% of max current (40-100W for most common COBs) where cobs beat HPS by 30% or more, and cost of parts for a DIY build is under $1/W. If you try to cheap out and run the COBs to their max and get down to <$0.50/watt you can do it but its only gonna be as efficient as the best HPS setup, so to an extent you get what you pay for.

the same is true for the "PCB" style designs- they throw a shitload of chips on a board and underdrive them to get the most out of each chip

So is it really the chips that make these lights expensive? I have seen decent COB's selling for $15/ pc on the net.

What kind of DIY set up would be comparable to a 600w and 1000w hps respectively?



Also what is offered for sale in terms of high end LED's? Are they better or worse than DIY?

What are the best lights on the market?


2 categories

1. Best for the money

2. Best light money can buy


Really trying to understand this tech, but it seems the most expensive leds are not white light...


Sorry for so many questions, it just seems we need one place for REAL good information on these.

I would recommend try youtubeing Growmau5. Good place to start, accessible and quite entertaining, a great deal of people who got here the last couple of years are here because they saw his videos. If youre into DIY he has a good series on how to. But remember that some of the advice regarding what brand of cobs might be out dated, especially cree cxb. Either that or reading around in the led section.

You may find that your about to fall down The Rabbithole...

6 months ago I had never heard of COB LEDs, and knew next to nothing about LED grow lights in general....then out of curiosity I peeked into said "rabbit hole"
Those videos led me right into the abyss!!!! Hours of pouring over data sheets and learning the lingo turned into : 4 panels of EB strips at 200+ watts from the wall each, and an 8 COB Veg rack later, and my underground Lair is GLOWING at 40% less power consumption with comparable results......

ceccorp said:

So is it really the chips that make these lights expensive?

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well its usually marketing that makes them expensive

chips
drivers
thermal solutions (heatsinks/fans)

are are about the same percentage of cost (20-40% depending on setup)

ceccorp said:

What kind of DIY set up would be comparable to a 600w and 1000w hps respectively?

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a 300-400W and a 600-700W respectively in most cases. and there are a ton of different ways to get there

ceccorp said:

Also what is offered for sale in terms of high end LED's? Are they better or worse than DIY?

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generally same performance but you are paying for plug and play and any certifications they may have gotten. there really is no "secret sauce" contrary to mfr claims. HQ lights are HQ lights and perform relatively equally

ceccorp said:

What are the best lights on the market?

2 categories

1. Best for the money

2. Best light money can buy

Click to expand...

commercial or DIY?

ceccorp said:

Really trying to understand this tech, but it seems the most expensive leds are not white light..

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that doesnt make them the "best" necessarily

white light works so well and is so cheap and commonly available that many (not all) mfrs try to trick up their spectra just to stand out from the pack. im not saying augmenting whites with monochromatic LEDs wont help efficiency, but im saying the cost difference is not justified in all cases

ceccorp, listen to cobkits-- he really knows what he is talking about and while he is a vendor (which I am typically skeptical about), I have never seen him spout how great he is and how bad everyone else is. He is always providing quality information to all. You mentioned $15 cobs -- he has very good quality cobs as low as $8 each! And no I am not affiliated in any way to cobkits. Check out his website.

I'm way down the rabbit hole now and have now built cob lights and LED strip lights. Read, read, read, and ask. There are great people here that will help you help yourself.

I started with a prebuilt 90w tunable blurple cob. This is the best I've grown with it. 13, 10cm colas. This image is missing 3 because I wanted some early smoke.

This plant is a mystery bean. And I've no idea the true weight I got. I don't own decent scales. But the buds were dense and heady.


Now I'm on to something like this.
Upgraded to 180w of 3500k white phosphor cob. This one is DIY. But honestly. If you can do it better than what I did. It looks really well done. And the results should impress you. This is the same plant as above. Just on its second run. Only just starting show bud sites.I've yet to see how much better this one performs. But, from the dense regrowth. I'm going to say it was money well spent.

I also would be curious of the cost of a 300-400w DIY COB build to replace a 600w HPS. Bonus if anyone can link to a grow. Looking through threads and watching Growmau5 but theres so much info here....

http://www.cutter.com.au/proddetail.php?prod=cut3122 4 COB, 400w Vero 29 kit. This one is newer. And has more efficient cobs.

http://www.cutter.com.au/proddetail.php?prod=cut3103 6 COB, 400W Cree kit.
This one is older. But provides more cobs to allow better light spread.

CobKits said:

well its usually marketing that makes them expensive

chips
drivers
thermal solutions (heatsinks/fans)

are are about the same percentage of cost (20-40% depending on setup)


a 300-400W and a 600-700W respectively in most cases. and there are a ton of different ways to get there


generally same performance but you are paying for plug and play and any certifications they may have gotten. there really is no "secret sauce" contrary to mfr claims. HQ lights are HQ lights and perform relatively equally



commercial or DIY?




that doesnt make them the "best" necessarily

white light works so well and is so cheap and commonly available that many (not all) mfrs try to trick up their spectra just to stand out from the pack. im not saying augmenting whites with monochromatic LEDs wont help efficiency, but im saying the cost difference is not justified in all cases

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What would be the best commercial lights available? Any way to determine exactly which chips these lights use?


Why would it cost more to use multiple different chips?


I see some people using very high watt diodes and some sticking to 5w.

@CobKits is an excellent resource. He will simply not steer you wrong. He's also a great source for DIY parts and kits, hence the name.

Others who can help you include @Stephenj37826 and @robincnn, they run HLG and have a lot of kits and complete fixtures at various price points.

I ran LED for a year or two and I would not grow with anything else unless I was forced to. There simply isn't a better light source for horticulture available anywhere else for any price. That includes the sun.

Study up. Light bulbs are already obsolete. It's only a matter of time before they're more costly, as well.

I replaced 3k of HPS with about 1800 watts of COBS....gained a lower room temperature, less watts at the plug and a higher yield....the info is out there to make it happen...