a bit of a diy growlight for lettuce im working on

[wd409]

howdy folks, I bought some led tv's with cracked screens a while back and this particular one (a 26") was the easiest one to work with for this cause of its housing, tell me what ya think, will it work, will it burn itself out? lets make some predictions!

in this shot we see 4 strips of 8 led's each, I concluded the strips run on 24v so im using a sony 24v 2.2a adapter i had on hand, the bridge that connects them however, connected them in series, so I had to ditch that and wire them up like this. the wires are soldered in and then taped to ensure they dont touch the metal.

however, I wasnt sure if steps needed to be taken to protect the leds from over current, I had this uninformed feeling that they didnt, it just seemed to me like they only pull what they need, but I needed to be sure

490mA, nice! that works out to 15mA per led.


this is some white reflective thing that was already in it, i simply stuck it back in

and it also had this diffuser bit, not sure im going to keep that yet so it is just lightly taped on for the moment

I turned all of the room lights off for these next 2 shots, gives you some idea of how bright it is

leaned it away from the wall a bit

other things I still need to do are find an adapter plug so i dont have to cut the cord on my sony brick, im also going to put a 1 amp fuse in there, i figure a dead short will go to max load and a 0.5 might pop when there isnt a problem since the load is so close to that, i might also play with one of my dimmers and see how that works out..

I havnt checked to see what the brick pulls from the wall during all of this yet but plan to, hopefully not very much.

so what do ya think, will she grow lettuce? i think it will, lettuce doesnt seem to care too much what kind of light it gets as long as it gets plenty of it, this certainly has plenty to give

 

[wd409]

rounding up, ive concluded that the led's pull 12 watts from the power brick (.5 amp @ 24v), and that the brick pulls 22 watts from the wall (.2 amp @ 110v). my seeds wont bere here til end of the year so ive gotto wait a little while to see if its going to be effective

 

[toxcrusadr]

Just ran across this. I tore down a TV a couple months ago after recapping and finding it had a cracked screen anyway. I found that LED array and kept it same as you did. I was going to use it for a shop light - with the diffuser it looks just like a fluorescent ceiling fixture.

Any idea what the light spectrum is on these? i.e. do you get any UV out of them? I'd leave off the diffuser, because if there is much UV, that thing will probably eat it.

 

[Decatur Greg]

You want red and blue for plant growth when using LEDs. Google LED grow lights and you can see some examples.
These appear to be white and they might work for plants. Put them VERY close to the plants to avoid the plants getting "leggy".

Definitely don't use green... plants don't use that wavelength for growth (that's why they look green to us... they reflect that light back).

 

[toxcrusadr]

They're white because that's what TV's have for back lights - at least this one did. I suppose one could change them out pretty cheaply, but it kinda defeats the purpose of recycling the broken TV.

 

[wd409]

what kinda light you want depends on what you wanna grow, these are cool white so they should be somewhere in the 6500k range which is ideal for growing lettuce and other things that dont need to flower. if you're gonna grow things that need to flower then you want to add warm white to the mix so you get the 4500k range as well

btw, the coolwhites are considered the red wavelength, warm whites are the blue wavelength in a setup like this


I included a picture of the lettuce, its growing a little slow which i guess is because the light just isnt that powerful, and maybe because ive got the diffuser on it, but it is growing and its doing just fine. the frame for this has room for many more led's so im planning to add more at some point, this will continue to be a low power panel but im going to get it up to around 30 watts or so. im also gonna try taking the diffuser off and try it that way.

 

[wd409]

on a side note, in my eagerness to get it going i forgot to pack the soil down at either stage or let it settle on its own after watering, so half the lettuce fell down and died, what remains tho ive been picking a handful of each day to give the guinea pig, i pick whatever is biggest so its never gonna look TOO big no matter when i take the picture

note2: i dont like how small that picture is on here so heres the full sized one