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Basic LED questions, for starters...

Roguejim

Roguejim

I grow some seedlings in a 2ft x 4ft space, under two T8 fluoro fixtures (32-watt, I think). Each T8 fixture holds two T8 tubes (6,500k). Now for the questions. If I switched to LED,

1) Would my plants grow faster?
2) Would my energy bill increase, decrease, or stay the same?
3) How much would I spend for LED lighting adequate for this space? Thanks
 
better growth?
Thing about LED is you can produce more of the PAR wavelengths so wasting less lumens. In the table below you can see how traditional lighting (compare your T8's to T5's except they have half as powerful). You produce good Veg(400-520) waste a lot in the middle and have little leaf / flowering / bud growth(610-700).
 
40jbiHP.png

 
Another way LEDs affect growth is you can switch out the LED that is more efficient for the growth you are wanting. In the seedling to maturity stage you want more blue light (vegetation growth) and some red for leaves. When you plant reaches maturity you can swap some of the blue for more red to get more flower/bud/fruit growth.
 
more efficient?
above you can see the efficiency column, per watt the led system is giving more than twice as much usable plant energy. This means you could potentially use 1/2 the amount of lumens to grow the same plant.. makes sense right?
 
also LEDS point straight down with 100-120degree viewing angles at the plants, there is much less light lost and no need to reflect
 
how much?
So to equal your t8 11,200 lumens, half = 5600 lumens give or take 
 
IF you build it yourself you can pick the combination of colors u want...
3 cool white x 1 blue 2 red
3 red 3 blue
6 white
 
a 30w driver and 3x10w leds are about 16$ on ebay (x2)
now u need a place to mount it... 8ft aluminum channel is ~ 10$ at my lowes
then u just need a spare power cord to wire the drivers into... free hopefully
some spare wire / solder for connecting the leds ... free hopefully
== 50$ give or take
 
edit: oh and i forgot to mention leds have a running time of 50,000 hours so you won't have to replace them for a long time, where as t8 / t5 have 10,000 running hours. If you calculate that into the price equation as well you can see it's actually cheaper over time.
 
 
disclaimer: this is all theory based, no idea if this world actually work in practice.
 
Google up those T8 LED replacement "bulbs". If theyre less than 64W you should save on electricity. If they put out just as many or more lumens than your two T8 bulbs then they should be fine for growing if all youre doing is raising seedlings for spring. I think they might even make those as "grow" lights too using red and blue.
 
I built a 125 watt LED light using blue, orange, deep red, and infrared. Out of all the diff types of plants I grow peppers like it best. That one only covers a 2x2 area.
 
Really if you make your own panel you'll save $$$ big time. It's very doable, just be creative. Source for the material and check what's needed.

The hardest part for me was waiting for my LEDs from China and soldering them together. Lol.


-Walt
 
just don't get stuck on lumens.
 
Lumens measure total amount of visible light. That's for us being able to see....
Photosynthetically active radiation (PAR) is the measure of light a plant absorbs for photosynthesis. This is how you should measure grow lights.
 
This picture should help
pargraph.jpg
 
OKGrowin said:
better growth?
Thing about LED is you can produce more of the PAR wavelengths so wasting less lumens. In the table below you can see how traditional lighting (compare your T8's to T5's except they have half as powerful). You produce good Veg(400-520) waste a lot in the middle and have little leaf / flowering / bud growth(610-700).
 
40jbiHP.png

 
Another way LEDs affect growth is you can switch out the LED that is more efficient for the growth you are wanting. In the seedling to maturity stage you want more blue light (vegetation growth) and some red for leaves. When you plant reaches maturity you can swap some of the blue for more red to get more flower/bud/fruit growth.
 
more efficient?
above you can see the efficiency column, per watt the led system is giving more than twice as much usable plant energy. This means you could potentially use 1/2 the amount of lumens to grow the same plant.. makes sense right?
 
also LEDS point straight down with 100-120degree viewing angles at the plants, there is much less light lost and no need to reflect
 
how much?
So to equal your t8 11,200 lumens, half = 5600 lumens give or take 
 
IF you build it yourself you can pick the combination of colors u want...
3 cool white x 1 blue 2 red
3 red 3 blue
6 white
 
a 30w driver and 3x10w leds are about 16$ on ebay (x2)
now u need a place to mount it... 8ft aluminum channel is ~ 10$ at my lowes
then u just need a spare power cord to wire the drivers into... free hopefully
some spare wire / solder for connecting the leds ... free hopefully
== 50$ give or take
 
edit: oh and i forgot to mention leds have a running time of 50,000 hours so you won't have to replace them for a long time, where as t8 / t5 have 10,000 running hours. If you calculate that into the price equation as well you can see it's actually cheaper over time.
 
 
disclaimer: this is all theory based, no idea if this world actually work in practice.
Click to expand...
 
Could you post a link for "a 30w driver and 3x10w leds are about 16$ on ebay (x2)"?  I need to see exactly what you're talking about. 
 
Also, when you say
"IF you build it yourself you can pick the combination of colors u want...
3 cool white x 1 blue 2 red
3 red 3 blue
6 white",
 
what type/shape LEDs are you talking about?  I see all kinds of shapes and sizes. 
 
What's your take on LED T8 replacement bulbs?  Thanks.
 
Roguejim said:
 
Click to expand...
I'm talking about cheap Chinese LED's
 
LED in series constant current, add voltage.
 10w led uses 10v, 900ma === 30v 900ma
 
 
30w driver waterproof AC in
specs say:
INPUT AC:85-265V 50/60HzAC:0.3A
OUTPUT DC:15-36VDC:0.9A±5%30W Max
a note about the driver, even if a LED fails it will lower the voltage so you wont burn anything, aka graceful degradation. 
 
blue 2$ each
 
red 3.5$ each
 
white 1$ each

=========
i'm going to make a grow light DIY build later btw.
 
The problem is you are constructing the light and is a little harder and less easy to service if maintenance, to mitigate this some you can:
Buy some cheap connectors and do this ( light gray is the connectors). and hook them up between driver and leds, even can hook up a power cord that has modular connectors for connecting how many of these boards you want.
HxMJZwR.png

You want more light? add another board of these. You want different colors? switch out one of the LEDS. very easy to do.
 
i have 0 opinion on led replacement tubes because i haven't researched them. ( google / amazon / ebay search reveals they are expensive and may require removal of ballast)
 
I have been looking at Cree based HP LEDs, and from what I have seen the driver selection is the key to most successes.

The Aluminum Block/heat sinks seem to be disproportionately priced, but necessary.

Check with me at work next week Jimbo.
 
I built 4 custom sized panels, which fit in one of those really small 18 x 24" greenhouses. They have alternating rows of red / blue LED weatherproof strips. If they're under powered, things will get funky, you will hear people reporting defective strips, with some elements not emitting. It's due to under amperage (user error). Anyway - so far so good knock on wood. I am glad to share any and all info. Here is a pic of the setup, with the 260w power supply on the stool. The supply runs cool. The greenhouse is 82 degrees inside. The plants have only been under this light.

DSC09641_zps8fe23d06.jpg

 
 
 
1800379_10203069977973284_1693518359_n_zps1d8f4f80.jpg

 
http://www.amazon.com/gp/product/B00BMHLWSO/ref=oh_details_o00_s00_i01?ie=UTF8&psc=1

http://www.amazon.com/gp/product/B00BMHP960/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

http://www.ebay.com/itm/171202336797?var=470321590552&ssPageName=STRK%3AMEWNX%3AIT&_trksid=p3984.m1439.l2649
 
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