New CO2 grow with Cree COBs

[George2324]

I could use some help with people who have used cree cobs and know how close they can get the canopy without bleaching

I'm setting up my new grow using a vertical system as it makes better use of my space


1 cxb3590 per square foot with a 90 degree lens

I'm going to be running co2 the issue is even with vertical setup the plants will grow to 2 feet tall each and the cobs will be approx 13-15 inches away from canopy due to limitations on the space

I was thinking of running the cobs at 2100ma but I'm not sure if 12 inches would be too close even with co2?

Could anyone who uses cobs give their specs and how close to canopy they get the cobs?


Since I only need 2 feet of canopy penetration I could possibly go for more cobs per sq ft and reduce the drive current If that would be better.

Cheers

 

[George2324]

Bump has nobody had any experience using cobs?

Would just like some stats on drive current and canopy distance so I can try and work out best coverage for my grow

Cheers

 

[LEDBud]

You want at least 50w sq.ft up to a maximum of 100w sq.ft

So your golden with the cxb3590 cobs powered at 36v x 1400 ma for 54w or with proper cooling 36v x 2100ma for 75w sq.ft


A Umol rating of 700 is a high number to shoot for with 500 being middle ground with 300 Um considered low but adequate.

look into the Cobs Umol rating with a 12 inch footprint @ 12 and 18 inches and remember the cobs are more efficient power to Par output wise if powered to 50w


I like to use 65w sq.ft with four 175w draw 100x 3w chip panels hung at a distance of 10 to 15 inches

My panels 65w sq.ft is probably similar to the crees 50w sq.ft par output

 

[George2324]

That's great thanks it helps what do you mean by the 100 x 3w panels? Do you run cobs? If you run cobs which current and how far away are your cobs?

 

[George2324]

When I look for umol rating what confuses me is what distances are those umol ratings based on?

12 inch to canopy or 30 inch to canopy. Surely the umol rating could be 10,000 if measured a cm from the cob

I found a video on YouTube of someone measuring par of cxb3590 driven at 1050ma and got 750 par at 22 inches.... so in theory due to inverse square law I'd be getting 1400 par atleast at 12 inches? He was however using lenses so that could possibly account for deeper penetration

 

[LEDBud]

I am not using Cob's although I have four 100w cobs ready to mount I'm currently using Panels.


The lens goofs the results concentrating the natural spread of the chip into a tighter beam which reads as a high par value

What they don't brag about is the tiny footprint it leaves you with comparatively , although they do have 120* lenes .. so who knows.

Par doubles every foot you move it closer to the plant


Most people run the Cree cobs @ 50w -55w for the maximum efficiency it provides plus its easier cooling and for good reason , longer life and a better gram to watt ratio

 

[George2324]

I was thinking of running one cxb3590 per square foot at 1750ma with 2 680nm 3w and 1 620nm 3w and 1 royal blue surrounding it.

My only concern is causing bleaching on the tops from this.

I run 1 plant per square foot so to get perfectly equal coverage so I don't have runts on the outsides I plan to have one cob above every plant. I want to change over my entire setup all at once but it's a big price tag and due to cost of shipping from china don't really wanna mess up and have to order different drivers. I plan to add the ability to dim anyway.

I assume due to my limited height then I should definitely avoid lenses? Even though I will have plenty of coverage at 1 per sq ft?

 

[LEDBud]

Don't worry about bleaching worry about the plants out growing your space instead. You will need to raise the lights many times to accommodate the plants growth if you notice a little bleaching raise the light a few inches higher problem solved.

Its how Everyone does it.

now if your growing in some crazy little cupboard with no head room I advise you to find an alternative space what ever it may be tent , spare room mylar curtain anything but a tiny little cupboard type space ..

People use Closets with success there is no concern with headroom with them

also plants need at least 2x2 ft floor space each unless you stunt the fuk out them them , which beginners seem to be drawn to , so watch out for that.

 

[George2324]

It's a custom loft grow no other way I'm afraid. I do have quite a bit of head room but to get more plants in I am doing a vertical setup and mounting all the cobs vertically.

Which leaves about 80 cm or so between the vertical tube fixture and the pvc vertical pipe the plants will be in.

It's perfectly possible to do as vertical plants that are 2 ft tall 60 cm actually only stick out 45cm horizontally . Due to growth at 45 degree angle I just need to make sure the LEDs are dialled in.

I have a seperate veg room that I keep them in until 3 week of flower to control the stretch so once they are in the flower room they won't really get much taller.

I've read every single thread I can find on these cobs trying to find peoples experiences with canopy distances but only bits of information around which most has incomplete data to be able to come to any conclusions so was looking for peoples experiences on here.

I would think due to the nature of the cobs being so customisable though it should definitely be possible for me to dial this system in perfectly

My plants are grown as a sog so they only need 1ft of space

 

[LEDBud]

In your case don't use 1700 ma. use 1400ma

Forgot over driving them run them as the pros do at 50% output 1400ma 55w

Its the best output to use especially so in your small space but even in a large room its best for maximizing the Cobs efficiency and lifespan.


Surely those points are important to you if not they should be.

 

[George2324]

Don't get my wrong it's not a small room. It's gonna have 72 2ft tall plants in here. With co2 at 1500ppm which should allow them to take up to 1500 umol of par I beleive. If 1400 is recommended I can still use 1750 ma if neee be and easily dim down to 1400 right? That way if 1400 isn't causing burn I can slowly dial it up

 

[LEDBud]

That's the best way dialed in to your gardens requirements , you will be set using adjustable drivers.

I really have to throw my cobs together have the drivers and heat sinks just need the power connectors ..

 

[Lost In Nugs]

I like the idea of LED next to COBs. I am building a light with it. 3500K Vero 29 SE and some LED near it. I think i will use 5W Epistar royal blue and deep red or Osram Oslon SSL80 LED. Not shure yet.

My 8 COBs run at 40W each about 18-20 inches from the plants. 320W for 6 sqft + 18W Far red flower initiator

6xClu0481212 4000K and 2x Vero29.7 3500K


You said 1 cob plant. 72 cxb3590? .

Current Grow SeymoreNuggets Flowering Journal - Nebula & Atomical Haze - Soil - 2x3 - 420W DIY COB

My journey seeking the light. Found some
SeymoreNugget's DIY talk - Building lights - Sharing ideas

 

[George2324]

Yeah that's right I've been in touch with kingbrite for 72 of them. I won't need far reds forflower room as I'll build them into the veg room as I do a 5 week perpetual by keeping the first 3 weeks of flower in veg room. Really helps to keep tight nodes too.

Yours are 20 inches from the canopy? Is that just preference or do you get bleaching any closer? That's worrying if I won't be able to get mine closer than 20 inches as I say I need to be able to run them at 12 inches preferably