Using LED'd as lighting

[legendaryfrog]

hi everyone

i was surfing the net recently (specifically here http://www.rexgrigg.com/co2.htm ) on how to start a planted aquarium. i was shocked at the light demands for a 40 gallon tank (like 200 watts). that got me thinking, why not use LED's? they have low power demands, and ive seen them used in growing plants.

any ideas how i can build a LED light source for my plants?

[legendaryfrog]

do you think an array of 200 red LEDs and 60 blue LED's would provide the right "spectrum" for JUST GROWING PLANTS?

[WeeNe858]

you should just make a rainbow led light strip XP



http://www.solarisled.com/

happy birthday

[ErrorS]

I know this is an older thread but I thought I should say something.

LEDs are not as efficient as normal flourescents. Especially when you consider it is very hard to direct LED lighting unlike with flourescents or MH.. a normal LED will output 1/5th the lumens per watt than a high quality T5 flourescent will, only slightly better than incandescent.

Just a warning.. I don't know about intensity, how well it puts out light in certain spectrums, etc. Lumens per watt obviously isn't the end all of light measurements. Not sure about space requirements per lumen vs MH, flourescent, CF, HO flourescent, incandescent, etc.. and they have many, many other advantages over other lighting.. they're far less fragile, have a much longer life, probably a color temp more accurate than flourescents (I'm guessing they can reach a truer high CRI like incandescents, MHs and Halogen)..

[loaches r cool]

LEDs are not as efficient as normal flourescents. Especially when you consider it is very hard to direct LED lighting unlike with flourescents or MH.. a normal LED will output 1/5th the lumens per watt than a high quality T5 flourescent will, only slightly better than incandescent.

I'd have to disagree with directing light part of that. Thats one of LEDs advantages is you are pretty much utilizing 100% of the light since its so focused, whereas flourescents illuminate 360* and need a high quality reflector to recover most of the light. Most LED output 15-30 degree angle, just a few are in the 45 degree range. And you dont even need to mess with any reflectors. BTW, to calculate the lumens of an LED here is a calulator http://led.linear1.org/lumen.wiz Here is a wiki that lists the effeciencies of various light sources (at the bottom) http://en.wikipedia.org/wiki/Luminous_efficacy and it claims that white 'prototype' leds (not in production yet???) are at 150+ lumens/watt, higher than T5. There regular rating given to white leds is 26-70 lumens per watt. I have however calculated the L/W of a few random LEDs and they were all 30 lumens/watt and less. I dont think the technology is there yet, I am sure in the years to come LEDs will be far more effecient and more common for these applications. There are a few folks though using LEDs w/ planted tanks already, its been a while since I have seen any updates with em though. With LEDs you can target certain wavelenghts a little better too.