Importance of 460nm red LEDs?

[Weezard]

Aloha Khyberk,

You said; "Going over 5w for emitter power is pointless, you start hitting multi-chip emitters and they're fairly inefficient as it is. "

I have to disagree
In truth, everything from 2W. on up are multiple emitters.

My hands-on experience indicates that 5W. chips are very good, but 15W emitters are superior.
For actual growing that is.
I'll leave the why of that for the mathturbaters.

And, I gotta ask.
Did you ever try buying direct from Ledengin?

They sent me to mouser's

No pickin' fights, jus' stating facts.

Aloha, Y'all

Weezard

[DreadedHermie]

I'll betcha Ledengin would sell the 15W 660's now, because Mouser isn't carrying them anymore. Sales / cust service is ext. 115. Question is, what's their minimum order?

[khyberkitsune]

Aloha Khyberk,

You said; "Going over 5w for emitter power is pointless, you start hitting multi-chip emitters and they're fairly inefficient as it is. "

I have to disagree
In truth, everything from 2W. on up are multiple emitters.

My hands-on experience indicates that 5W. chips are very good, but 15W emitters are superior.
For actual growing that is.
I'll leave the why of that for the mathturbaters.

And, I gotta ask.
Did you ever try buying direct from Ledengin?

They sent me to mouser's

No pickin' fights, jus' stating facts.

Aloha, Y'all

Weezard

None of my 3 or 5w emitters (used for biofuel algae production) are multi-emitter. They are a single chip with a massive tweaked lambertian emission pattern. Photon flux density is more efficiently increased by making more powerful single emitters rather than using valuable die real-estate making multi-emitter chips, primarily because the chips in multi-emitter diodes are spaced apart and create a 'ghosting' effect. Sure you get more chips out of a multi-emitter size but the costs increase and flaws happen much more often as you scale down as well. Just one issue one deals with when working in the semiconductor industry.

Savage Marine uses 10w single-chip emitters for their lights on their boats, multi-chip emitters just created consistency problems in light, with different emitters fading at different rates, drastically changing the emissions. Those are probably some of the best I've seen in a while, with their irradiant output per watt being better than most 15w multi-emitters.

I think LEDEngin sent you to Mouser because you weren't likely a major manufacturer of a product - LEDEngin prefers bulk sales versus smaller retail, despite the higher profit margins direct retail offers, and would prefer the recognition from retail resellers than direct retail. My company works somewhat the same way, unless you're in a high company position (engineering, research, or C*O) or are a reseller, we will usually direct you to one of our retailers or to our website, unless you have a very specific custom request, in which case you deal directly with me, and if need be I fly out there.

I will concede that most 3w+ LEDs are multi-chip, but you can find single-chip emitters, and they are (so far) offering better performance than higher-powered multi-chip LEDs.

[khyberkitsune]

I'll betcha Ledengin would sell the 15W 660's now, because Mouser isn't carrying them anymore. Sales / cust service is ext. 115. Question is, what's their minimum order?

One minute, I'll call and find out since I have a line with them already.

[khyberkitsune]

One minute, I'll call and find out since I have a line with them already.

Direct extension 115 doesn't work, but option 3 always does I left a message, nobody answered.

[stra8outtaWeed]

I'll betcha Ledengin would sell the 15W 660's now, because Mouser isn't carrying them anymore. Sales / cust service is ext. 115. Question is, what's their minimum order?

hey Hermie...look into my album on pictuer of my lights and hit my email...got a few things i'd like to discuss with ya if ya don't mind

[Weezard]

"I will concede that most 3w+ LEDs are multi-chip, but you can find single-chip emitters, and they are (so far) offering better performance than higher-powered multi-chip LEDs. "

Mahalo, saved me diggin' out da cyclops.

I do appreciate your point of view and approach, as a producer.
"offering better performance "
As a personal grow amateur, ainokea 'bout "da last drop":rastasmoke:

I cut my power bill by 2/3rds and grow bodaceous meds.
'snot da mos' efficient, but it works a treat!
Have no intention to market any of it.
I jus' givem, make da world a li'l mo' betta, yah?:hippy:

Aloha, -not jus' a word.

Weezard

[thepaan]

For the whole grow or just for flowering?

For the whole grow. Flowering is accomplished by changing the length of the night (long nights induce flowering in most cannabis strains). The problem with this is short days don't give as much light as long days and we want as much as possible for maximum growth (we aren't growing leaves during flowering but more light still makes bigger flowers). Since this is a phytochrome response, we can try to a) avoid visible red or 2) supplement with far red around 730 nm. I've never tried either. There is a range of response for some plants (all the way into the blue) but others require specific wavelengths (around 660 nm) to induce flowering and likewise the reverse conversion isn't always exactly at or exclusively 730 nm. I don't know the specifics for cannabis.

Google book - scroll down to chapter 1, page 3:
Marijuana Botany: Propagation and ... - Google Books

More on phytochrome:
floinduc

How many watts of LED do you find necessary per square foot?

I put together this spreadsheet a while ago to figure out exactly that. Start on the 22moles/m2/day (E,39) and adjust from there. You will need to know the light output of each LED in watts and the area in square meters (C60).

https://spreadsheets.google.com/ccc?...5MzhzZlE&hl=en


Also, the path oxygen takes to the thylakoids is irrelevant to the point. Rubisco will react with either oxygen (photorespiration) or carbon dioxide (photosynthesis). When the availability of either gas is altered it directly alters the probability of each function. I was wrong, however, on the 1 for 1 ratio. I meant to say 3 CO2 for each oxygen but in actuality I can't recall if it is exactly 3 or a little higher. And the LEDs too: I've never really looked at yellow LEDs too much I just (ass)umed they were like white LEDs.

You got me again, khyberkitsune. :P

[thepaan]

I just remembered where I read that: Molecular Mechanisms of Photosynthesis (ISBN 9780632043217), page 182. "...the rate of carboxylation is only about three times the rate of oxygenation under normal physiological conditions."

[thepaan]

Aaaaaand I finally found that greenhouse article again. Skip to page 18 (or read the whole thing like I did :P).

http://www.nyserda.org/InnovationsIn...u_Albright.pdf