DIY LED with COBs - small medium and large grows

[Toaster79]

I'm flowering in a 4 feet by 4 feet tent. I see most DIY builds here use 9 or 12 LED's for that space yet the manufacturer of these lights stated that 5 of these would be enough.

So my main question is do I really need so many? Especially considering that even though I'm running below the 5 recommended by the manufacturer (I'm using 4), why would that be? Is there something that I can do to improve light output so that 5 would be sufficient and still keep the lights alive for at least a couple of years. I obviously do not expect them to last the 4 years that the warranty covers on these lights that I currently use, but a couple of years would be plenty. With the advances in LED technology I would expect to replace them by then anyway

Now honestly, did you read this thread from page 1 or did you click your way to the last page to ask all those questions?

 

[kriaze]

Toaster79, I did believe that your 1st statement was aimed at my question but I did not realise that the second one was, it seems we have a misunderstanding. There were other posts and I assumed your second comment was aimed towards someone else.

I do understand the 35-50w per square foot rule but I also believe that it's more about PAR per sq ft rather than watts alone. Thanks for reposting and bearing with me

 

[kriaze]

I also did read this thread from page 1 before signing up. It's something that I do on other sites, I like knowledge

 

[kriaze]

Maybe I should also add that I'm not looking for definitive answers so much as educated opinions from those with more experience of not only DIY builds but growing too.

I'm a member of a different site also but I don't see enough information there in regards to DIY LED's, hence why I joined here after reading such good information.

 

[Toaster79]

Maybe I should also add that I'm not looking for definitive answers so much as educated opinions from those with more experience of not only DIY builds but growing too.

I'm a member of a different site also but I don't see enough information there in regards to DIY LED's, hence why I joined here after reading such good information.

Then I suggest you keep on reading.

 

[kriaze]

I will, I will also keep on waiting for an educated, unbiased and honest opinion. Thanks for responding

 

[Toaster79]

.I do understand the 35-50w per square foot rule but I also believe that it's more about PAR per sq ft rather than watts alone. Thanks for reposting and bearing with me

Where are the PAR, PPF, umoles numbers comimg from?

From the light source. Once you know your light source and what that light source is capable of in form of numbers/parameters mentioned above, you can start doing some math. And this math will have to include light spectrum, efficacy, light patterns and maybe some other things.

 

[kriaze]

I understand what you mean and I have read a fair amount and can read a chart regarding some of these things but as mentioned earlier in this thread there are discrepancies between charts and real world experience. I lack the experience of using these DIY builds so it is simply a case of my asking for more experienced opinions instead of being led down a jolly path of self enlightenment of everything mathematical and a new adventure of learning. Lights are new to me as I have only used them for a year or so, which is why I was looking for people with real answers.

 

[Toaster79]

I understand what you mean and I have read a fair amount and can read a chart regarding some of these things but as mentioned earlier in this thread there are discrepancies between charts and real world experience. I lack the experience of using these DIY builds so it is simply a case of my asking for more experienced opinions instead of being led down a jolly path of self enlightenment of everything mathematical and a new adventure of learning. Lights are new to me as I have only used them for a year or so, which is why I was looking for people with real answers.

This is the only real answer I can give you so far:

About 35 days

 

[kriaze]

They look great, I haven't read your current thread as of yet but you stated earlier that you use a 6 cob setup, so that is one more than was recommended to me by the manufacturer of the lights that I use. Yet still half of what some of the builds are using that I have seen on this thread so far, so you can understand my questioning as to whether there is gain there is to be had by using more, or whether there is a best way to drive less or whether my light system is currently weak, will be ok with one more, or will need 8 more.

I was after a helpful opinion to bridge the disparity between builds per sq ft and my lack of knowledge. Yours is one that helps a lot so thank you, if there are more with a reasoning behind it, experienced unbiased and helpful I would appreciate them all

 

[sixstring]

Im currently using 1 cob per sq ft and running them @1050ma and i like what i see so far.cant give much more advice since im still on my first crop,other than i will continue to build these bars and also experiment with the 1400ma drivers as well and maybe space my cobs to 14 to 16 inches on center instead of 12in.
In a 4 x 4 space i personally would run a minimum of 9 cobs @ anything under 1750ma.you might be able to use less if you drive them harder but most of us are running them soft for efficiency reasons.

 

[HughJassBud]

Sixstring and Toaster both are good people to listen to on this subject. I think if it were me in your situation.......wait, I am!

So my 2 cents.......there are a bunch of different metrics to consider like PFF, PAR watts, umols, and a hole bunch of scientific theory to explain why, in theory, x amount of watts is needed vs what you would use in HPS or other conventional lighting systems. In my humble opinion, this information can only take you so far. But I think you know this as you are already here asking questions like me. SOOO, what does matter? The only thing I really think matters at the end of the day is real world results, replicate-able and repeatable results. There are number of individuals doing this with varying degrees of success using a wide variety of LED technology. As far as cxb3590's are concerned, I would look at growmau5 on youtube if you want some really good real world results using this technology. What sixstring and toaster are saying is right in line with what Growmau5 recommends in his videos.....little surprise since it was sixstring that introduced me to growmau5.

To that effect my only critique is of size and density of the produced herb I am seeing. As such, seeing as everyone else is going with the 1 COB per square foot theory, I think I will do the american thing and push for more power. So, here in another couple weeks I will be starting a side by side pitting 16 cxb3590's (800 watts) vs 1000 watt digital HPS. I very well may find that past 1 COB per square foot there are diminishing returns though.....very very possible.

If I was more concerned with budget and trying to find the least amount of COB's to get the job done, I would probably build modular. Make a 4 COB setup and see how it goes. If you need more, get more. The 185h drivers are less expensive per COB than the 240h drivers....so it may be better to build in 4's than 5's....but whatever floats your boat! Just please post as I know I and probably several others would be interested to see your results with whatever you decide on.

 

[HughJassBud]

@Toaster79 right on man. It would be helpful if people would read through everything carefully in this thread. I know it is long, but the breadth of information covered should answer most questions if you're an intuitive individual. It took me a couple days and multitudes of google searches to get familiar with everything. Toaster has probably posted the bulk of the answers himself at one time or another.

If it's a battle of wits you've come for, you should probably arm yourself first.

 

[Purpletrain]

With the numbers starting to come in 400 watts of cobs needed to compete with a 600 hid
most people doing side by sides are using museum mogul sockets .
830 watts of cob to compete with 1000 watt
950 watts needed to compete with DE remember its not uncommon to see DE's pull 3.5 pounds off one light
And the truth is DE's have kick ass penetration ,,
Cobs are great but remember its a sacrafice more efficient means less yields and of course less heat ..
running them harder or to compete with DE then you will have heat issues cause you will be running them @ 52 percent efficient 48 heat
I have yet to see a tree grow with cobs 99 percent of the time
Cob Grows are SOGS
Once my back yard landscape is done i will run 800 watts COB 3500 k 4000k, 5000 k and 6500 k mixed and growing TREES so we will know how they truly compare to DE's in 25 Sq feet VS 1215 watt Nano un biased in 25 Sq feet TREE GROW

 

[Toaster79]

COBs driven softly won't have much penetration. Thats why I run my 3070 @2100mA. You people keep trying to compare a single 1kW light source to multiple 5-150W light sources and expect same results.

@HughJassBud those kits Cutter is selling are actually growmau5 kits. I've been using Cutter for LEDs for the past decade although being in Europe.

 

[Purpletrain]

lol toaster its not eye its them guys like Real styles Cob HPS killer etc etc
Its them cob growers ,led growers ,
shit that is what most sites Do here is the 650 watt LED or ob unit blah blah it replaces the 1000 watt Hid lol right bud ???
I am building 400 watt units 2 HGL 185's per unit but here is the kicker i am building stands on rollers i am hanging them ...
these are going to be run vertical as supplemental side lighting complimenting the Nano's
But for shits n giggles i may run a side by side

 

[HughJassBud]

To be fair, I have grown many "trees" in my time but often find they aren't any better than running a bunch of smaller plants, unless of course you're worried about numbers. I agree with you, LED and COB's are better suited to SOG style growing at the moment. However, is this a bad thing? When designing a grow or grooming a plant, do you not consider the light source and optimize accordingly?

More important, to me, would be yield per square ft of one vs the other, regardless of how you decide to grow. I have done pretty much everything in dirt at some time or another. Biggest nugz always came from the trees. Most consistent nugz came from a multitude of smaller plants. My harvest have mostly been about equal and I can't really say one yields more than the other, for me. Just my opinion though, your experience may differ.

 

[Purpletrain]

Well sure it can be bad thing when plant counts are the determine factor if your going to spend a year in jail or 25 years in jail i used to do sogs grows talking over 1200 plants in number of rooms and around 3000 total plant count including clones .
And no matter what theory on gram yield per sq foot a bigger plant will always out yield a smaller plant also it will be better quality being a bigger plant ..
From running these rooms your only harvesting 1/3 of the plant bottom is larf and crap B grade
and with that sog plant food increased man hrs increased right trust me i did it for 2 years non stop .
harvesting 5 - 6 pounds every 2 weeks my sogs consisted of min 4 week under 1000 watters veg from 2 " clones
from running 76 plant rooms i dropped to 12 plants and yielded more with extra 2 weeks veg 6 - 7 weeks veg but again perputual ..
man hrs on room easy 65 percent less time
when i watered my sog grows i would go through appox 250 gallons per 76 plants could you imagine going through 1 liter bottles of nutrients lol when i ordered nutes they came in 20 gallon totes that 2 part let alone other stuff etc
I am just saying not trying to swing my big dick lol
I lowered plant count and up my pot size to 34 gallon and did better overal in operation
lets face it its all about efficiency right ??
and for many going to cob there growing in tents closets reason they went LED or COB was to stay away from heat

 

[HughJassBud]

@Purpletrain

what kind of lights are you running? How many? How far from the canopy?

I have 0 experience with DE's, which you mentioned somewhere previously, I think. In dirt, SOG was pretty ridiculous man hours, but I had to worry much less about supporting massive nugs and tying up long branches.....so I guess I thought it was a wash more or less. Either way, dirt simply became to much of a chore for me. This is why I'm remodeling sort of and restarting with hydro. A sog doesn't seem like a lot of work to me when its just changing a reservoir or topping it off every so often. However, maybe time will change my tune on this.

A scrog is basically impossible as I veg and bloom in different areas. Sure there are some mobile methods, but I don't want to mess with all of that.

I'm all about big wattage for stupid penetration and ginormous nugz. No doubt. I love that shit. However, it's certainly not the most efficient way to do things and can be hard to manage in hot climates like the south west where I live. I think COB's have their place now, but I don't think it will be growing trees YET. I say yet because I think the technology will get there eventually. Also, keep in mind that all though a single COB running at 50watts no doubt has less penetration than an HPS, you're running it 12" closer to the plant and spreading them out in such a way as to eliminate shadows and equally distribute the light. SO, maybe you can grow trees if you do it just so. I would love to see it, I would love to see the DE's against COBS just for "shits and giggles". For my part, I'll compare HID to COB using the SOG grow. Maybe someday in the future I will switch back to dirt and try some trees too. Hopefully you will beat me to it! Do I think the nugz will be as big and dense from COB's as a 1000w HPS? .......I honestly don't know, my gut tells me no but I want to be optimistic.

 

[HughJassBud]

Have you checked with Jerry at King Brite for those Cree COB'S? The CXB3590 was about the same cost for me recently as the cxa3070 from mouser. Maybe you've stated previously that it's not an option for you though.

If you're running 4 COB per driver, I would use the meanwell 185h style driver. That will be perfect for running 4 COB devices. Make sure you order the driver based on the voltage of COB you select. (72v and 36v variant) I ordered these from Jerry as well.

So, for the price you're showing there I would get the CXB3590 as opposed to the CXA3070. Just my 2 cents