My Frustrating Journey to Find the Right LED Grow Light...

Rahz said:
The PPF as umol/s output is absolute and isn't based on distance. You're talking about a density reading under the lamp which is not the same thing.
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what do you mean, the measurement of PPF is taken from the spot. we know what the PPF is on the light. so why would distance not be considered?
 
Rahz said:
Comparing lumens isn't exactly the fair way to do it.

600w DE = 1.7umol/w = 1020 PPF
372w (2xT3-1750) 2.45umol/w = 911 PPF
450w (2xT3-2100) 2.3umol/w = 1035 PPF
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so you divide some umol density by wattage at some distance and not define it to get ppf? if im not mistaken then my 1200umol /350W would equal 3.42 umol/w
 
SoOLED said:
what do you mean, the measurement of PPF is taken from the spot. we know what the PPF is on the light. so why would distance not be considered?
Click to expand...

PPF is the amount of photons being emitted by the lamp per second (umol/s). Raising or lowering a light doesn't cause it to produce more or less photons.

PPFD is what the par meter is reading (umol/s/m2), but doesn't represent the average density of the space in which it's being used, just the average density of the space the sensor covers.
 
Purpsmagurps said:
so you divide some umol density by wattage at some distance and not define it to get ppf? if im not mistaken then my 1200umol /350W would equal 3.42 umol/w
Click to expand...

umol density (PPFD) depends on the area it's being used in along with other factors, so you can't extropolate the umol/watt second from a meter reading. If you know the PPF and output wattage then you can find the umol/j
 
RickyBobby26 said:
This post is very long, and it eventually asks "which should I buy", and it's not my intention to make anyone mad. So feel free to quit reading now if you're put off by such posts. Otherwise, I need and appreciate your help.

I seriously need an LED grow light to replace my 600-watt HPS in a 3'8" x 3'8" x 8' grow closet. I don't have the tech skills to build my own. But I have the money to buy a good light. I can spend up to $1500 (the less the better). But there seems to be no web sites dedicated to comprehensive, independent, unbiased reviews of LED grow lights.

I've been looking, researching, and reading for months. The only thing I'm sure of is that most companies exaggerate their claims, and I can't tell the difference between those that do, and those that don't.

I'm not interested in startup companies - only proven companies with many satisfied customers. And I’m not necessarily looking to increase my 600-watt HPS yields - just to replicate them with less consumed power and significantly less generated heat (my yields are very good).

I spoke to a Black Dog LED rep yesterday who wanted to sell me a Phytomax 600 for $1600. He said it would replace my 600-watt HPS, but would consume about as much power and generate about as much heat as said 600-watt HPS. Oh yeah? Then WHAT’S THE FUCKING POINT? Yet one web site that claimed to "independently review LED grow lights" rated the Black Dog Phytomax as the #1 LED grow light for 2016.

I’ve googled “Best LED Grow Lights”, and a thousand variants, and I get no consistent results. Most every so-called “review site” gives a very different “Top 5” or “Top 10” list. Very different. I found one web site that had a “Best LED Grow Lights” article for 2015, and another for 2016, and the two lists had almost no grow lights in common. That much variance from one year to the next from the SAME reviewers? No fucking way.

This smacks of “Good Reviews for Hire” that are little more than (un)veiled advertisements. The idiots kinda give it away when they conclude their “unbiased” review with something to the effect of “Let the XXX LED grow light improve your growing TODAY!”, and provide a direct sales link.

What I’d like is to find a “Consumer-Reports-like” web site that gives independent, accurate, unbiased (i.e. unpaid) reviews of modern LED grow lights.

Or get some recommendations here. Rollitup happens to be the most active LED commenting site I've found. So I'd appreciate ANY suggestions based upon the criteria listed in my post.

Thanks, or apologies, whichever is appropriate for your response.
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Two pages of minutiae and no one has asked you what your goals are? Tsk, tsk...

If you're just looking to replicate the performance of your 600W HPS lamp, save your money and just grab a fresh bulb. The savings in electricity alone isn't really worth the trouble.

If you want BETTER results than an HPS lamp can offer, NOW we have a decent excuse to throw good money at a sexy flashlight! So what's better? More PPfD and better spectrum, leading to more yield and better quality. Now, that's a worthy goal, amirite?

What gets you there in your 13 sq ft tent? Lots of things; my personal choice was two modules, each made of 4 CXB3590 3500K CD BIN 72V chips and driven by a Meanwell HLG 185H-C700B. Together, they'll pull almost exactly 450W while giving you somewhere in the range of 50% overall efficiency while producing a nice broad spectrum for the plants to bask in.
 
3500k is mostly yellowy orange spectrum and blue, basically no red to offset the blue, to what efficiency is worth sacrificing half your flowering spectrum intensity?
 
Purpsmagurps said:
frostier nugs, better smells, terpene profiles and pheno traits thats why
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There's no objective evidence I know of to suggest restricting the spectrum to blue/red produces more or better flowers than white LED. I and others would love to see someone do a well controlled grow off between them. Problem is most red/blue lamp makers refuse to provide electrical characteristics of their lamps so direct comparisons can't be made. I tend to suspect this is because they don't want people to know. I use white cobs because they put out a lot of micromoles per watt, and because the spectral distribution is similar to the Mcree curve. Both red and blue are important but the Mcree study doesn't suggest it will be best to use them alone. I think 3500K provides plenty of red. If I didn't I would be stocking them in 3000K, but I am more than happy to custom build lamps at any Kelvin temp the cobs come in.
 
ttystikk said:
Two pages of minutiae and no one has asked you what your goals are? Tsk, tsk...

If you're just looking to replicate the performance of your 600W HPS lamp, save your money and just grab a fresh bulb. The savings in electricity alone isn't really worth the trouble.

If you want BETTER results than an HPS lamp can offer, NOW we have a decent excuse to throw good money at a sexy flashlight! So what's better? More PPfD and better spectrum, leading to more yield and better quality. Now, that's a worthy goal, amirite?

What gets you there in your 13 sq ft tent? Lots of things; my personal choice was two modules, each made of 4 CXB3590 3500K CD BIN 72V chips and driven by a Meanwell HLG 185H-C700B. Together, they'll pull almost exactly 450W while giving you somewhere in the range of 50% overall efficiency while producing a nice broad spectrum for the plants to bask in.
Click to expand...

Thanks man.

My main need for a new light is heat reduction. July and August are brutally hot where I live.
 
because diy leds are super simple , can be as simple as order great parts, gently screw down parts, push wires in. hang

cxb3590 3500s at driven @ 2100 changed my whole life lol
 
Purpsmagurps said:
3500k is mostly yellowy orange spectrum and blue, basically no red to offset the blue, to what efficiency is worth sacrificing half your flowering spectrum intensity?
Click to expand...

Warm white phosphor spectrum is outperforming blue/red lights in both growth and efficiency.

That being said the warm white spectrum can be enhanced with deep red, Far red and UVA, UVB, and actinic blues for an even better spectrum. BUT warm white cobs by themselves still blow away blue + red lights.
 
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