Agent86

Re: fluorex
Hi Powercow9:

From what I've read the florex doesn't have the red color spectrum that the EVL does.
One of the things I really like about the EVL is how short the plants stay.
Everything I've read indicates that more red light will keep the internodes close.

Here's something interesting, if you let your plants have a small amount if infra red light shortly before the lights turn off the plants will stretch. This happens naturally outdoors at sunset. But by giving the plants a short exposure to red light, the affects of the infra red will be reversed. Very usefull info if your growing in a green house. To keep your plants short give them some red spectrum light just after sundown then shut the lights off for the night.

Sorry I'm so long winded.
Later.
86.

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JoseHempSeed

slow down with the calculators!

by definition, a lumen is equal to the luminous flux through a unit solid angle from a uniform point source of one candle, or to the flux of a unit surface area all points of which are at a unit distance from a uniform point source of one candle. the intensity of one lumen per square foot equals one foot-candle .

and on PAR: it also includes green. the only difference between par and lumens is that par is filtered (with very steep skirts) from 400 nm. to 700 nm. lumens are still a very good way to measure light intensity - some may even say better, since lumen measurement includes some uv and ir, as well.

hope that helps

regularguy

First off thanks go out to the agent for his willingness to do research. Well done.

The 12.6 you guys are talking about comes from the equation I gave earlier. I=L/A The area you are talking about is the area of the sphere that the light makes at a radius(d) of 1 foot. The spheres formula is 4pi(r^2). The 4pi is the 12.6 conversion number. So actually all the numbers are off because the conversion factor is not just 4pi but the equation for surface area of a sphere. You would use 4pi at one foot. All others would have to be adjusted by multiplying them by the radius^2 also. It just so happens that you don’t need to do this at 1 foot because 1^2 is 1. Agent can you send me the foot candle numbers and I can convert them all and post. You have done enough by actually getting the info. I will comment more after this.

I think lumens are good enough as long as you understand haw the emmited spectrum is distributed across the wavelengths.

JoseHempSeed

maybe if we looked at this a different way, it would help. everybody, put down your bongs and listen up.

our candle is a source of light. the amount of light the candle puts out is measured in lumens.

now, if we go 1 foot from the candle, that light is dispersed over an area. so we measure the intensity at 1 foot away (don't forget it's evenly dispersed) and say "ok, this brightness is what we will forever more call one lumen per square foot." that's the definition someone came up with way back when.

now we're measuring the light from a single candle spread over some area, which just happens to be 12.6 square feet, since we're 1 foot away. and we have, again by definition, 1 lumen over each of those square feet.

so what is the intensity of the candle?

gold stars to anybody who says 12.6 lumens!

so what going on is this: we are taking the intensity of the light put out by the candle (a point source with no area), and converting that to an equivalent amount of light spread over some area. and when we multiply the foot-candle readings by the 12.6 ft², we are going backwards and figuring what the intensity of the source (lamp) would be.

hope that helps

regularguy

"put down your bongs"
heh, let me think about that. NO. Its a spoon anyhow.

I think me and Jose are saying the same thing about the light calculations. Now another complication arises. If you are using the surface area of a sphere for this calculation that would be for the light without a reflector. Werent these readings taken with a reflector? Wouldnt that in effect cut the surface area used approximately in half?

choader

One question unanswered is coverage area. The light meter reading is the intensity at that point, expressed in lumens. The light output is fixed while the area (grow area) varies and the light must be spread over that area. Seems like projection pattern would be important? That's why we see the lower readings between the bulbs

Agent86 - were the bulbs vertical or horizontal? (sounds like vertical) Might be interesting to do a plot on lumens over area. for example, your measurements were right under the light. How about an inch off center? 2", 3", ...........

While the EVL certainly puts out alot of light, it may cover a smaller area than an HID.

Just some thoughts.

Choader

morphious1

So what is being said then ( seance everyone is bickering about lumens , we forgot why this is important :-) is that at 2 to 3 inches away with the EVL is about the same lumens as the HPS 400w at one foot. This is great news for small space growers!!

I have had similar results as well..

My High out put Compact Fluos put out this..

4 - 55 watt Biax high out put Compact Fluos. 2 - 6500k and 2 3000k with reflector. at 2 inches from light 4750 ft candles at 78 degrees. at 10 inches. 4250 at 70 degrees!

now that I know the Ft candel to Lumens conversion, I am a happy man !

I have been keeping the plants at about 3 inches away, at 4300 ft candels = 54,180 lumens!!

Regards.

Morphious

JoseHempSeed

morphius1, you're close...remember 1 foot-candle = 1 lumen/ft². that's the definition. (you are taking an intensity over an area). so when you measure 4300 foot-candles, that is the same as 4300 lu/ft². that's how much light you actually have illuminating your plants. the 54,180 lumens would actually be the equivalent intensity of the source.

choader, you're close, too. lumens is the measure of intensity at a point source (no area). lumen/ft² is the intensity of the light spread over an area. and right on about the area being illuminated, when you double the distance, you get only 1/4 the light...which is somewhat dependent on the shape of your reflector...

so back to the envirolites. if you could somehow get all the light out of one envirolite bulb and project it onto a 1 ft² surface, you would have 8900 lu/ft². THAT would be good - the sun illuminates the earth at about 10,000 lu/ft².

hope that helps

Agent86

Hi Grow Bros:

Regularguy : All the lights I tested were in the same type of reflector so yes the results will be a little skewed, but since all the bulbs were tested the same way the results should be pretty good for comparisons. As far as the reflector cutting the surface area in half, that would depend on how well the reflector reflects.
Here are the foot candles for one bulb.
1'=300
10"=700
8"=900
6"=1200
4"=1800
2"=3000
1"=4500

Here are the foot candles for 2 bulbs.
1'=8,750
10"=125
8"=1500
6"=1800
4"=2500
2"=3000
1"=3300

400w @ 1'=2250
600w @ 2'=5000
1000w@ 2'=5200
40w floro @ 1'=1800
40w floro @ 1"=3700
There you go Regularguy, have at it.

morphious1 & choader:
You are absolutely correct. For the small grower EVLs are perfect. Because you have to keep the EVL so close to the plant to get the lumens large growers would need lots of EVLs to cover the squar footage of a large grow room, making them cost prohibitive.

Thanks again Grow Bros.
86.

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powercow9

NP I nderstand completely.. PAR is kinda new and the light people are slow to move to it... They'll only use it if it can show their product is better than another. it's kinda like mhz.. it a good starting place to figure out computer power but it definatly doesnt give the whole story as far as computer power... I just wish more lights would use PAR. because 2 lights can have the same lumens but one can grow a plant and the other cant.

I'd love to find out the par value of those envirolights.. I suppose it's pretty high as the cri is so high... If anyone can get their hands on a PAR meter( yeah i know they are expensive) and let us know the par of the envirolights.

update sunmaster has adopted par and will list them on bulbs.

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