Cobs Suck !!

Southside112

Southside112

Well-Known Member
Just want to share my experiences with cob led's so far. So I have been running cobs in addition to other white led's for 4 years now.
Vero 29's to be exact. 4 years ago I bought a Timber 4vs which is a 400w 4 vero29 unit. I have replaced all 4 cobs already due to burning out and tonight 2 more burned out on me. 2 of the original cobs were replaced with graumaus pucks. So I have 2 pucks and 2 vero 29's on the unit. My current grow is in flower and stretching at the moment. I raised up my light like 6" tonight and got my par meter out. Turned up the power on the unit from like 60% power to like 80% power. Instantly smelled a burned electronic smell followed by flickering lights. Boom both cobs burned out and went dark. Took out the unit to much inconvenience as I have 4 flowering plants in my grow area. They were all burned up melted and black around the cobs.

Bottom line imo is cobs generate way too much heat in too small an area. 100w of cobs concentrated to an area the size of a key lime. Vero 29 cobs are the only ones to my knowledge that can run constant 100w most others run @ 50w. So this might just be a vero issue. But numbers don't lie. 6 burned out vero 29 cobs in 4 years.
I placed an order for 2 more graumaus pucks from rapid led tonight. So my unit will be a 400w 4 graumaus puck moving forward.

Never had an issue with the pucks or a 240w qb I have only cobs. So to anyone who reads this do yourself a favor and go the qb, strip or puck route. Save yourself all the hassles ive had to deal with. Thanks.
 
Southside112

Southside112

Well-Known Member
go go kid said:
yeah they are narrow of beam, more like a one plant light never tried quantam boards so dont know what they are. i like my metal halide and sodium lights
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Quantum boards are hundreds of individual led's spread out over like a 10"x10" area. Cobs are 100's of led's spread over a really small circle. Cobs throw light like a hps or mh, more of a conical area roughly 12-15" diameter depending on hanging height.
 
nunyabidness420

nunyabidness420

Well-Known Member
COBs were the best option for DIY before quantum boards came out.
But they're less efficient than discrete LEDs and have that narrow beam like you said.
I never had a problem with COB reliability though.
Do you think maybe COBs might have gotten tweaked during installation? If you flex them a bit or if the heatsink isn't perfectly flat sometimes a few bonding wires break and the whole unit fails after some time.
 
Southside112

Southside112

Well-Known Member
nunyabidness420 said:
COBs were the best option for DIY before quantum boards came out.
But they're less efficient than discrete LEDs and have that narrow beam like you said.
I never had a problem with COB reliability though.
Do you think maybe COBs might have gotten tweaked during installation? If you flex them a bit or if the heatsink isn't perfectly flat sometimes a few bonding wires break and the whole unit fails after some time.
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The 4 original cobs were installed by Timber and were installed right. Timber came out like 2 years ago and told all owners to take the reflectors off because others were having issues with them melting. I suspect it is a vero 29 issue. Too much heat generated @ 100w each. Like I said most cobs run @ 50w.
 
CannaOnerStar

CannaOnerStar

Well-Known Member
Southside112 said:
Don't get me wrong they grow great plants. Reliability has been the issue. Also the spread is a little narrow. You get much more even lighting with quantum boards.
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On the other hand COBs give out more intense light, which penetrates better. More light you get from smaller area, the more intense the light is and better is its penetration.

The reason why HPS penetrates so good is not because of some HPS magic, its just because it gives so much light from a single spot, which gives it a good penetration.

So i would say that it depends on situation whether less intense light from larger area is better, its better if you have low and wide canopy like when scroging properly, but with tall plants it might not be give as good lower buds. Also if you got a few COBs, you could place them more strategically than all directly above, getting more out of your lights.

Also lets say you have a HPS and you want 100w extra light from LEDs. Most likely it would be much better to get 2x 50w COBs you can place so that you get most out of their light than with a single 100w quantum board.

QBs also have more room for development than COBs and can be fine tuned better. COBs are what they are and ofc you could add some extra lights with them, but then it would be a set of LEDs and not just a COB anymore.

Im sure for most a good QB is a better choice, but it depends on the setup. So i think rather than saying LEDs are better than HID or that QBs are better than COBs or what ever, its best to figure out what suits best for a particular grow situation. None of them are best for every setup, but all of them are best for some particular setup.
 
Southside112

Southside112

Well-Known Member
CannaOnerStar said:
On the other hand COBs give out more intense light, which penetrates better. More light you get from smaller area, the more intense the light is and better is its penetration.

The reason why HPS penetrates so good is not because of some HPS magic, its just because it gives so much light from a single spot, which gives it a good penetration.

So i would say that it depends on situation whether less intense light from larger area is better, its better if you have low and wide canopy like when scroging properly, but with tall plants it might not be give as good lower buds. Also if you got a few COBs, you could place them more strategically than all directly above, getting more out of your lights.

Also lets say you have a HPS and you want 100w extra light from LEDs. Most likely it would be much better to get 2x 50w COBs you can place so that you get most out of their light than with a single 100w quantum board.

QBs also have more room for development than COBs and can be fine tuned better. COBs are what they are and ofc you could add some extra lights with them, but then it would be a set of LEDs and not just a COB anymore.

Im sure for most a good QB is a better choice, but it depends on the setup. So i think rather than saying LEDs are better than HID or that QBs are better than COBs or what ever, its best to figure out what suits best for a particular grow situation. None of them are best for every setup, but all of them are best for some particular setup.
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I liked the cobs for all the reasons you mentioned. They did penetrate the canopy very well. Again reliability is the issue. Dosent matter what lights we have if they don't work. Thank God i had another light to put in my grow area or my whole grow would have been compromised.
 
Horselover fat

Horselover fat

Well-Known Member
Southside112 said:
The 4 original cobs were installed by Timber and were installed right. Timber came out like 2 years ago and told all owners to take the reflectors off because others were having issues with them melting. I suspect it is a vero 29 issue. Too much heat generated @ 100w each. Like I said most cobs run @ 50w.
Click to expand...
Not so much a cob issue, but less than perfect fixture design. Not enough cooling for 100w.
 
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