Help with LED

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
User avatar
sofaspud
Posts: 531
Joined: Wed Feb 13, 2002 1:01 am
Location: San Antonio, TX
Contact:

Re: Help with LED

Post by sofaspud »

My only comments...
LED technology is rapidly changing, but to my knowledge it would take extremely large LEDs or an awfully large number to use as grow lights.
A hole is the absence of something. A nothing cannot be directly moved.
The entire subtopic reminds me of the "I've got a hole in me pocket" segment of The Beatles' Yellow Submarine movie.
Engineer1138
Posts: 458
Joined: Thu Feb 05, 2004 1:01 am
Location: Minneapolis, MN
Contact:

Re: Help with LED

Post by Engineer1138 »

I don't know much about lizards, but aquarium supply stores will have fluorescents of varying color temperature. Reef lights in particular are full spectrum and available in wattages from 5W fluorescent to over 300W metal halide. You can also find Actinic blue pretty cheap. The lights need to be changed every 8 months to a year because the color temperature drifts over time and causes undesirable plant growth, so it does get expensive. Take a look at http://www.marineandreef.com/shoppro/po ... psCor.html

ISTR reading a paper online by one of the state University Agriculture extensions that concluded there was no appreciable difference between "grow lights" and common household fluorescent lights but I can't find the link or remember any more details.
Newz2000
Posts: 507
Joined: Wed May 18, 2005 1:01 am
Location: Des Moines, Iowa, USA
Contact:

Re: Help with LED

Post by Newz2000 »

Originally posted by Engineer1138:
ISTR reading a paper online by one of the state University Agriculture extensions that concluded there was no appreciable difference between "grow lights" and common household fluorescent lights but I can't find the link or remember any more details.
I remember learning that at one time too, but have nothing to back up my statements with.
Robert Reed
Posts: 2277
Joined: Wed Nov 24, 2004 1:01 am
Location: ASHTABULA,OHIO
Contact:

Re: Help with LED

Post by Robert Reed »

Mr Al

"Excuse me if I have egg on my chin" :)
rshayes
Posts: 1286
Joined: Tue Mar 04, 2003 1:01 am
Contact:

Re: Help with LED

Post by rshayes »

Try a google search for "fluorescent lamps plant growth". The general consensus seems to be that white fluorescent tubes are about as effective (if not more so) than the "grow light" type of tube, and are far cheaper. The "grow light" tubes may have a better spectral distribution, but this is apparently offset by lower efficiency. Some people recommend mixtures of "warm white" and "cool white" tubes.

Fluorescent tubes are about 20 percent efficient, so a 40 watt tube will put out about 8 watts of light. I suspect that LEDs are still less efficient than fluorescent lights and getting the same amount of power out would require a large number of diodes.
stevek
Posts: 9
Joined: Fri Nov 11, 2005 1:01 am
Contact:

Re: Help with LED

Post by stevek »

Mainly and those are good ideas you posted, but mainly the benefit of the LED's is the electric bill at the end of the month! you can run these suckers off of 6v golf cart batteries wired in series and parallel to provide a 12 volt supply and use solar power to recharge the things during the day, and not run out of power at night. If you attach them to AC, your bill at the end of the month would be very very low! Heck, i am looking into the cost savings of bulbs for the house. their much cheaper than flourescent! I have a flashlight here that has led bulb in it, and have had it for 2 years now and have never replaced the batteries in it!
Originally posted by Matt Nuzum:
I don't know how big of an area you want to cover, but the full spectrum LEDs aren't that cheap, and most LEDs, while bright, cover a relatively smaller area.

Have you checked into the fluorescent tubes used for pet lizards? I understand they're very similar to the lights used to make plants grow and can be purchased much cheaper than $180.

I'm sure there's some benefit to the bulbs that run so much, but you may find cheaper bulbs at a petstore or mailorder business that caters to reptiles.

10 years ago I found "grow lights," incandescent/halogen bulbs that produced the correct light to help plants grow indoors. Home depot wasn't around my area then, but I'd look there to see if they have them.
stevek
Posts: 9
Joined: Fri Nov 11, 2005 1:01 am
Contact:

Re: Help with LED

Post by stevek »

Originally posted by MrAl:
Hello there,

On Topic:
Led's dont light that big of an
area, so it would take many, many LED's to
do plants! There is always Lumileds i guess.
It's still going to cost a bunch to do a wide
area.

Al
Hi Al,
you are right they don't cover a large area. thats why i said it would take around 1080 red leds, and 240 blue leds to cover a 4' square area.
But then when you talk blue leds your talking about seed starting and seedling growth anyway. The reds are control measures to keep them from growing short and fat. if you put reds in exclusively you get leggy plants.

hmmmm i am still looking at it. spent several hours today at several sites! The LED's aren't that bad in price if you buy in bulk, unless you go with the luxon suckers. now them things are pricy! 14 bucks a piece!
User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Re: Help with LED

Post by MrAl »

Hello again,


ROBERT REED:
I guess i got a little carried away with my
post anyway :)
I pretty much agree with you about the electron
flow, but in theory i like to use positive to
negative flow (conventional flow) because the
math simplifies a bit and then applies to other
areas like mechanical engineering, fluid flow,
etc,. Most of the stuff i've studied in the past
relies on conventional flow so i've used that
mostly. I know it's not physically accurate, but
since it's easier to use that and the end result
turns out the same (for circuit analysis) i keep
using that but always remember that there is a
big difference between theory and physical
reality except on paper.

stevek:
Yes, those LED's are quite high priced. I've
found the 1 watter's put out about the same as
15 smaller LED's, roughly, but then the
mcd rating of some of the smaller LED's came
up since then.
You're right in that it will take many LED's
to do what you are talking about doing. Did you
estimate the cost of such a project? Dont forget
you have to either build a power supply or
try connecting them in strings to roughly match
the home AC line supply (not sure what you have
120vac or 220vac in your location), and you'll of
course have to rectify that AC first.

Your notes on plant growth are very interesting,
and i'd like to hear more about this once you
get the light built up and grow some plants with
it. Perhaps you can get veggies to grow better,
or bigger, or something that improves the value?
Maybe you could let us know what you end up
doing too...building something or purchasing
something.


Take care,
Al
LEDs vs Bulbs, LEDs are winning.
stevek
Posts: 9
Joined: Fri Nov 11, 2005 1:01 am
Contact:

Re: Help with LED

Post by stevek »

Originally posted by MrAl:
stevek:
Yes, those LED's are quite high priced. I've
found the 1 watter's put out about the same as
15 smaller LED's, roughly, but then the
mcd rating of some of the smaller LED's came
up since then.
Yeah i am seeing that. Boy they sure have changed in 15 years!!!
You're right in that it will take many LED's
to do what you are talking about doing. Did you
estimate the cost of such a project?
I haven't put too much effort into it yet, just trying to do a determination of what will work for me.
Dont forget
you have to either build a power supply or
try connecting them in strings to roughly match
the home AC line supply (not sure what you have
120vac or 220vac in your location), and you'll of
course have to rectify that AC first.
I can do that pretty easily with a 300watt switching powersupply from a pc! They are already wired up for 12v, and 5v.
I can take 12v supply side to recharge the bank of batteries too along with the solar panel. Then the voltage can be dropped down low enough to power the led's if i need it.
Your notes on plant growth are very interesting,
and i'd like to hear more about this once you
get the light built up and grow some plants with
it.
I am having some success with flourescent, but not as good as i want. I thought that the leds would preform better at delivery of the specific bandwidth needed for plantgrowth without being required to replace bulbs every 8 months or so.

Perhaps you can get veggies to grow better,
or bigger, or something that improves the value?
Maybe you could let us know what you end up
doing too...building something or purchasing
something.
Veggies is one aspect i am looking at, especially supplying to the "chefs" in different restaurants during the winter time. The biggest complaint i have with hydroponics is there is no flavor in the produce. BUT if i utilize soil and lighting conditions i might be able to produce some decent produce.

Biggest dang problem i get now is the DEA and the BATF showing up searching my place every now and then. I have beehives and buy 500 pound barrel of sugar to feed them during the winter, and i get BATF showing up all the time. Like dudes get a clue I am raising bee's not brewing whiskey!
User avatar
sofaspud
Posts: 531
Joined: Wed Feb 13, 2002 1:01 am
Location: San Antonio, TX
Contact:

Re: Help with LED

Post by sofaspud »

You seem committed to the investment, so attaboys from me for tackling this unique project. I've never heard of someone using this approach and it'd be interesting to read how it works out for you. Best of luck with it all.
And I haven't missed the irony of still using the sun to grow your crops, though in a roundabout way!
From the nitpick dept., whiskey is distilled, not brewed. :-)
User avatar
Chris Smith
Posts: 4325
Joined: Tue Dec 04, 2001 1:01 am
Location: Bieber Ca.

Re: Help with LED

Post by Chris Smith »

Have you considered "ALL Spectrum" lighting [pure white light] like they use in the film industry, High wattage grow lights, etc., and then Beam splitting the different frequencies of light using a simple prism or three.

This way it is actually tunable, [any variable choice of all the RGBs, etc.] while several prisms will allow you to mix more than one color, and the wattage will be sufficient for growing.
stevek
Posts: 9
Joined: Fri Nov 11, 2005 1:01 am
Contact:

Re: Help with LED

Post by stevek »

Originally posted by sofaspud:
You seem committed to the investment, so attaboys from me for tackling this unique project. I've never heard of someone using this approach and it'd be interesting to read how it works out for you. Best of luck with it all.
LOL I hope the investment will pay off. In the very least it can be used as tax writeoff!

And I haven't missed the irony of still using the sun to grow your crops, though in a roundabout way!
GRIN, you know your right, didn't think of it that way myself! :) Mostly was thinking about the pocket change involved.
From the nitpick dept., whiskey is distilled, not brewed. :-)
And again you are quite correct, i must bow to the error! It is distilled and not brewed! Shame on me, bad bad bad! I should know better being from the north georgia hills and only 8 miles from bill elliots shop!
stevek
Posts: 9
Joined: Fri Nov 11, 2005 1:01 am
Contact:

Re: Help with LED

Post by stevek »

Originally posted by Chris Smith:
Have you considered "ALL Spectrum" lighting [pure white light] like they use in the film industry, High wattage grow lights, etc., and then Beam splitting the different frequencies of light using a simple prism or three.
THe problem with high wattage grow lights, I.E. Mercury vapor and The halide?? lights, is the electric bill goes from 200 a month to 2000 a month.
Not very cost effective!


This way it is actually tunable, [any variable choice of all the RGBs, etc.] while several prisms will allow you to mix more than one color, and the wattage will be sufficient for growing.
The thing is that plants aren't that picky. They like reds and blues. Uhmm i think around 450 range and 625 range.
I would think that i could adjust the frequency of the light by mixing colors. I have been looking at several possibilities. mixing reds, blues and redorange leds, and greens and turning on a certain percentage of each to get the colors i want. I also am looking at the rgb's but they are so darn expensive that they would have to do the job of a bunch of leds to be worth the cost.
But then again, its either 12' of halide or merc vapor lights and a 2000 a month bill or the cost of building some led panels to hang above them. The LED panels will save me in the long run i am thinking.

I can build panels of reds, of blues and orange reds and greens and mix and match. I am thinking that if i use a flourescent diffuser, i might be able to mix the colors into a constant color.
not sure of that yet.

at any rate, i am only going to build enough to do one square foot for now to see what it takes and evaluate the cost of doing 12' afterwards.
Shoot if i can get this to work, It will give me double use of my land.
I am also working on building my house underground using shipping containers, and i plan on putting some new greenhouses on top of the house. If i utilize some extra shipping containers as seedling starters, that will free up some space in my greenhouses so that i can grow more plants. Right now i use 1 of my 4 greenhouses as seed starting and plant propagation, and if i can move that underneath the greenhouses, it will double my space for a very low low low cost, PLUS i don't incur the added cost of heating and cooling.

Its slow but its moving along. This spring barring any unforseen losses in my plants, i will have some capital to build with. I have already started the next years plants and everything at this point is paid for. Now all i need to do is cash in on the profits. But you know things rarely work out as you expect them too! So i ain't holdin my breath!
User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Re: Help with LED

Post by MrAl »

Hi again,

stevek:
You're right in that the rgb LED's probably isnt
the way to go because it would take way too many
of them and the cost would just be too high.

One other thing i think you might look at
before calculating the savings (or not) on the
electric bill each month is the relative efficiency
of LED's over fluorescent type lights.
I havent looked at this myself in quite a while
now so perhaps someone else could post an effective
way to compare fluor to LED's, as they stand in
the present time.

One advantage LED's with optics has is that
the light is much more directional than with
fluor tubes. This means most of the light can
be concentrated on the work area (plant area).
This in itself may reduce costs, but remember
that 1 watt still requires 1 watt of
power no matter what kind of light is used :)

I would suspect you already own a good light
meter (?) so you can do some measurements before
you fully invest in anything. Perhaps purchase
one (or two) lights of the type you wish to use
and do an experiment to determine what the cost
might be by mounting each type of light over
the work area and measure these quantities:

1. power input for each light
2. average light intensity for each light on leaf

You can then figure out how much advantage the
LED light has over the fluor or whatever lights
you are comparing by comparing the power inputs
and light intensities for each type of light
source.
Instead of using a leaf of course you would use
a set distance, like maybe four feet or whatever
is the closest distance you can use with an
actual plant.

As a final note (not sure if this has been mentioned
yet) is the high powered LED's "with optics"
concentrate the light to a more narrow area
and would be more suitable to use for plants then
the bare "emitters" that are sold for less cost.
The emitters radiate over a much wider area
and also the bare emitters dont have heat sinks.
You'd have to mount them on heatsinks yourself
in order to take full advantage of the full power
output (a 1 watter might only run at 1/4 watt
without a heat sink as anything higher might burn
it out fast).

Also, you may wish to check out the life expectancy
curves of LED's run at full power and half power.
Run at half power (puts out roughly half the light)
the LED's could last much longer than two times
as long. When an LED dies it's usually not all
of a sudden either...it gradually dims over a
period of time. This means you might have to
use some sort of measuring device to check
LED outputs over time to make sure the plants
continually get the light they need.
(as a side note, perhaps a good measure of this
is plant stalk length over time: less growth
means light has dimmed, everything else constant).

Since it sounds like you might invest quite
a bit into a new lighting system it will be
worth investigating these things...


Take care,
Al


Take care,
Al

<small>[ November 15, 2005, 04:24 AM: Message edited by: MrAl ]</small>
LEDs vs Bulbs, LEDs are winning.
Mike6158
Posts: 409
Joined: Fri Nov 12, 2004 1:01 am
Location: Weimar, Texas
Contact:

Re: Help with LED

Post by Mike6158 »

I made a little strip of 9 red and 9 blue led's (alternated red and blue in groups of 3) for just this purpose (growing plants in the winter). I never have tried it on plants but the theory seemed valid. The one thing that I don't quit get is how to calculate the light energy requirement of a plant. Is it like a solar cell (w/m²)? I suppose that the energy "released" by the array of led's is "calculatable"? Or could I use a photographers' light meter to take a reading? Or do you just build it, plug it in, point it at a plant, and hope for the best :D
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."
Post Reply

Who is online

Users browsing this forum: No registered users and 33 guests