Dunge
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This is the sort of post that I need more of.
For me it is about electric costs.
On the question of penetration:
Do we not want all of the light we provide the plant to be absorbed and converted into biomass. So in a perfect world, no light would make it through the plant. I think this may be why many LED grow pics look so dark. The energy is tuned so as to be taken up by the plants.
Does this make any sense?
See, that's the issue to begin with.. led's should be at least 75% of what you were using with hid's. 50% is bs.
As for "penetration".. depends on the led's lumen output.. not the wattage. A 1w Cree XP-E Red 630nm has 45.7 - 62 Lumens @ 350mA.. bin depending. "Dorado 1w 624nm" has 32 Lumens @ 350mA. Cheap Chinese has even less.
http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=/leds.htm
Obviously more lumens = more penetration. But even with a 250hps in my 18" x 30" SoG cab, maximum 24" plantlets.. I still needed to "shade leaf".. strategic removal of fan leaves, but only when the node has enough growth to sustain itself without a fan leaf... ie: growth has enough foliage to collect the energy it needs.
And just because the manufacturer used a certain percentage of red to blue.. did he take into account that blues traditionally put out 1/2 as many lumens than the reds? That's where using 1w and 3w diodes on same panel actually makes sense. 1w reds set for 100Lm a piece, followed by 3w blues set at 100Lm a piece. .. That may be an issue with some panels right there.. the ratio should be x amount of red lumens compared to x amount of blue lumens.. not x red stars compared to x blue stars.
Cheers............
exactly they shouldn't advertise it as equivalent to 600 if you actually need 450 to match the results which i still think is unlikely.
You have to take into account that a plant only uses about 1/2 the wavelengths that an hps puts out, so at least 1/2 that hps is "wasted". And contrary to what Lost is saying about "intensity"... Dunge was right... you're not using every friggin' colour of the sun to grow your plants, only some reds and some blues.. colours that aren't very bright to the human eye, so they do look "darker" than with a hid. Put a meter under them though, and the lumens will suprise you.
http://i851.invalid.com/albums/ab80/thereal_spuzzum/hpsusableoutput.jpg
You have to take into account that a plant only uses about 1/2 the wavelengths that an hps puts out, so at least 1/2 that hps is "wasted". And contrary to what Lost is saying about "intensity"... Dunge was right... you're not using every friggin' colour of the sun to grow your plants, only some reds and some blues.. colours that aren't very bright to the human eye, so they do look "darker" than with a hid. Put a meter under them though, and the lumens will suprise you.
http://i851.invalid.com/albums/ab80/thereal_spuzzum/hpsusableoutput.jpg
if spectrum didn't matter, then you'd use halides the whole way..Cheers...........
I tried meds grown under led's once and it was pretty crappy.
If that's the case, then you'd grow the entire cycle with hps.. from seed. But you don't. Sure, more lumens.. but wrong spectrum for vegging.
If it was just intensity, then using 1w Cree whites are the same, if not more lumens per watt as a 250w hps, 400w hps, 600w hps, and even the 1000w. And the fact that you can get the led's within inches of the plants.. guess what.. your "intensity" just increased.
250w hps = 28-29000 Lumens / 112-116 Lumens per watt.
400w hps = 50000 Lumens / 125 Lumens per watt.
600w hps = 90000 Lumens / 150 Lumens per watt.
1000w hps = 130000 Lumens / 130 Lumens per watt.
That's without the overhead that the ballasts use...
250w hps input= 300w
250w hps output = 250w
----------------------------
28-29000Lm / 300w = 93.3-96.7Lm/W
400w hps input = 470w
400w hps output = 400w
----------------------------
50000Lm / 470w = 106.3Lm/W
600w hps input = 695w
600w hps output = 600w
----------------------------
90000Lm / 695w = 129.4Lm/W
1000w hps input = 1100w
1000w hps output = 1000w
------------------------------
130000Lm / 1100w = 118Lm/W
Cree XP-G Bin Codes:
http://i851.invalid.com/albums/ab80/thereal_spuzzum/lumens.png
http://i851.invalid.com/albums/ab80/thereal_spuzzum/bin.png
Farming's a lot more than just light intensity.. whether you want to accept it or not, "spectrum" plays a much more important part when it comes to photosynthesis.. that's something you learn in grade 10 biology. I guess only us old farts can understand this though.. sorry if you're having problems.
Cheers...................
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