Flower pics 2018

Dkeppel

Member
The technology is developing rapidly that's for sure.

The proof is in the grow and your COBs look like there kicking ass too me, I'd use them for sure.

Loving the La Nina, just another MNS strain to add to my list .....

By the way what is that you've lined your grow room with ? I brought a house recently and I'm in the process of building my grow space, I was just gonna use mylar but it's dam expensive.

Also what model COB did you build your flowering light with ? You mentioned the model of the seedling light but couldn't find the model used in the 300/250 watt lights.

Last question, what's the height between your lights and the canopy ?

I'm considering if maybe I could use COBs, I'm only going to have a 3 foot 2 inch ceiling height is my problem.
 
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Byorn

Active member
Hey Dkeppel,

i`ve used radiator isolation foil. Also the isolation thats used for laminate flooring works pretty well. Its not the best reflective material, mylar is better i thought about 10%. There is some test around on https://www.wietforum.nl/topic/76556-verschillen-in-reflectiemateriaal-op-de-wanden/ it`s written in dutch so not sure if you can read it. If remember right de mirror sheets have the best reflection and plain white did pretty well also. I choose the isolation material because of it`s price and the ease of placing it, and i didnt wanted to wait till paint fumes dissapeared.

The COBs for the 300w light rig:
Cree CXB3070 BD 3500K driven at 1400mA the output is 49,8Watt 170lumens/Watt

the 250W light rig:
Cree CXB3070 BD 3500k driven at 1100mA the output is 38,5Watt 178,5 Lumens/Watt
Cree CXB3590 DB 3500K driven at 1400mA the output is 48,7Watt 186,5 Lumens/Watt

My rule of thumb for how much led power is needed is 325-350W per square meter.

the height between the leds and the canopy i have around 20-30cm it is mostly based on the distances between the leds as a rule of thumb. Some tops are way further away and still fatten up just nice. Some of the tops get as close as 10cm from the Cobs and still not a problem as long the climate is optimal.

Seeing those numbers again, i like to point out that a regular HPS lamp with subtracted lost light to the reflector and walls would produce somewhere around 100lumens/Watt. its not hard to see why Leds are a true HPS killer in terms of g/Watt ratios.

I think you can get away with Cobs if you dont drive them to hard, they could get closer to canopy, and you would need more Cobs for the same output. That also increases initial cost but also increases the efficiency. But for that extra space i think strips are your best option, assuming you also want to flower in that same space. That would leave you with +/- 70cm for plant height taken in mind the pot size and distance to the led strip and the strip itself. Optimal for sog scrog.

The COBs need a serious heatsink with a ventilator or a even a bigger one if you dont want an active fan on it. With fan you loose about 10cm height and distance to canopy is higher so that would leave you with +/- 40cm Plant height. Still doable but more of a challenge and i can not reccomend it remembering my micro grows in the past.

hope thats some answers you where looking for, and otherwise just ask :)

greetzz
 

Dkeppel

Member
Thanks Byron, I'll try hunt down some of that radiator foil, I'm from New Zealand so there is a high chance it's very expensive or not available at all locally.

I was aiming for about 300 watts a square metre, I couldn't remember where I got that number, good to know I had the right idea.

I completely forgot about dimming, it pretty much eliminates the the issue of distance between the canopy and lights.

I should of remembered, I used it in my recent micro grow, I'm pretty sure I had the light as close as 7cm from the canopy, dimmed right down, I didn't need the spread so why waste the power right ?

I built my 150watt light using Bridgelux EB gen2 3500k strips, my only complaint is flowering seemed to take a little longer to start then under HPS, I think this maybe due to not enough far red in the spectrum.

I'm going for 3 square metres in this new space, I didn't think about the heat sinks and fans on the COBs, I think i'm right to use strips for this space, every mm of ceiling height matters.
 
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