213 Watt LED Nirvana Northern Lights Grow

DrFever said:

right now LED's are to expensive or the big guys you know the ones making huge yields not talking average grower talking organized crime billion dollar industry would be using it and there not right now
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[FONT=Arial, Helvetica, sans-serif] per 1 k and that's over 1 gram per[/FONT]

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DZLHIT said:

Panel draws 300 watts

View Image

Most 1k HPS in a hood, no glass, read 1400 around 24 inches. And then we get into PUR vs PAR... and LED wins.

Sorry this guy tried to rain on your parade GP, keep up the good work you do. I'm watching!

How are those screw in bulbs working for the veg space? I am running 220 watts of PL-L's in mine and want to switch.

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PAR: Photsynthetically Available (or Active) Radiation. All radiation with a wavelength of 400nm to 700nm.

PPFD: Photosynthetic Photon Flux Density. A way to measure PAR. It's the number of photons of light falling on a given area in a given amount of time, and its units are micromoles per meter square per second (µmol m-2 s-1).

Lux: A measure of illuminance, measured in lumens per square metre.


Now, a given light source will produce a certain amount of its output as PPFD. This amount can be related directly to illuminance by way of a multiplier, and, importantly, is constant for each source type*.

Here are the multipliers to convert illuminance in Lux to PPFD for some common light sources:
Code:
Source Multiplier
Sunlight 0.0185
Fluorescent (Grolux) 0.029
Metal Halide 0.0141
Fluorescent (865/840) 0.0135
High Pressure Sodium 0.0122

Figures provided by Apogee Instruments.
So, we can multiply the Lux value by the multiplier in the above table to find the PPFD in µmol m-2 s-1.


Worked example:

Code:
60 cm x 60 cm space (0.36 m²)
250 Watt HPS lamp (33,200 lumens)

Lux = (total lumens) / (total area in square metres)
= 33,200 / 0.36
= 92,222

PPFD = Lux x factor
= 92,222 x 0.0122
= 1,125

What level of PPFD is good? I don't know, but I imagine that, like everything in this game, "More!" is probably the answer**. The proper information is almost certainly out there though.

As a reference, direct sunlight at midday, with a Lux value of about 100,000, will provide a PPFD of around 1,850 µmol m-2 s-1.


There's also another measure of PAR, and that's YPF (Yield Photon Flux) PAR. It's weighted more to the plant response curve, and the red end of the spectrum, than PPFD and so is probably a better measure for growing purposes, but I don't have any conversion factors.


Finally, here's a table showing the PPFD for a few lamp types and sizes:




*For suitable values of 'constant'. It's mostly constant, but may vary with specific or specialist lamps.
**There probably is a maximum upper limit, and the law of diminishing returns will probably start to take effect before that limit is reached.

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babelfish said:

here's one answer:
http://www.thctalk.com/cannabis-forum/showthread.php?55580-Converting-lumens-to-PAR-PPF

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GP73LPC said:

also forgot to mention i picked up two 5000K LED bulbs from Lowes that i am using for clones and moms.

i'll get a pic up of those a little later too.

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GP73LPC said:

WTF ???????

so tonight i decided to take a little peek on the babies with a green LED cap light i have.

much to surprise there was NOT total darkness. glad the plants aren't mature yet.

my LEDS aren't shutting all the way off. is this a timer problem? seems like i have read that some where.

do i need to invest in a better timer?

HELP !!!! need to fix this before we get sexually mature.

https://www.icmag.com/ic/picture.php?albumid=42786&pictureid=1022103View Image

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