LED grow lights

[66 north]

I was recently interested in the use of LED's for growing plants. They are getting cheaper and better so I emailed a company called Solaroasis about there ruby grow bar product http://www.solaroasis.com/. It turns out they haven't conducted many tests on aquariums since these were designed to grow terrestrial plants. We've been talking for a while and as result I've been given the opportunity to try out these terrestrial lights.

The primary purpose for me getting these lights is to use them as supplemental lighting on my planted tank. I'll probably end up trying a few different configurations but for now I've put two of the bars over my 90 gallon. My tank already had pretty good lighting with 4x55watt CF lighting but there were a couple of dim spots due to shading that could be made better. I've noticead two things over the past 4 days 1) Pearling starts to occur earlier in the day, 2) once started, pearling can continue with just the LEDs on.

The ouput spectrum of these lights is strange to view but it's stated clearly in the pamphlets that came with them "lights for plants not people". This means the colour they give is heavy in the blue and red with almost no green or yellow, or very little visible light. Pics will follow when my camera gets fixed but for now I've scanned a graph showing the output of these and several other types of light. Probably of most interest to us is the flourescent lights compared here, I've been told they are Sunwave (CF lights) and Growlux normal output.



For a closer look:
http://www.pricenetwork.ca/gallery/a...t%20output.jpg

[tazcrash69]

OK, being a gadget lover, I'm subscribing to see what happens with this!!

[daFrimpster]

Very intriguing! I am looking forward to following your adventure! thansk for sharing.

[TheOtherGeoff]

only thing i could see worry some is the lumen output. LED's dont have the technology behind them yet to have good lumen output for reasonible prices. in a short tank this wouldnt be a problme but they might have trouble getting into a deep tank. plus if the plants started to grow over the top of the tank the light wouldnt be able to get around the plants as easy as say a PC

[66 north]

Originally Posted by TheOtherGeoff

only thing i could see worry some is the lumen output. LED's dont have the technology behind them yet to have good lumen output for reasonible prices. in a short tank this wouldnt be a problme but they might have trouble getting into a deep tank. plus if the plants started to grow over the top of the tank the light wouldnt be able to get around the plants as easy as say a PC

That's a very valid point and part of the reason I'm trying this newer LED technology out. These particular lights haven't been tested beyond 18 inches from what I've been told so I'm pushing the limits here. As far as lumen output is concerned I know what you mean but I think we'll have to throw that exact type of measurement out the window since lumens are a measure of visible light to our human eyes. According to that graph I put up we're not supposed to see much light ourselves but the plants are. If needed we can probably get more technical data from the company but for now all I can do is look at plant
growth.

The price for one of these bars may be high initially, but over the long term keep in mind that you won't have to change the bulbs for something like 8 years, and the amount of power they use is much less saving you money. We'll have to do some cost assessments though to see how it works out.

[hOAGART]

how bout some pics with the LED's on your tank ?

[66 north]

Yup, for sure, lots of pics will follow as long as things stay interesting. My camera is just getting fixed at the moment, apparently it doesn't like rain.

[SCMurphy]

The bars don't look useful for aquarium use. The lights look like they are too far apart. The individual lights look like they have great potential though, I bet you could cluster up six of them over a 10 gallon and kick butt.

[66 north]

They actually have a fairly decent spread of light but I see your point. I'll have to try them out longer but I think the individual lights would be perfect in situation where you have say a wimpy light demanding plant that you want to keep but don't want to add another whole cf bulb, due to size and heat issues. In that situation you could position it directly above your plant of interest. I should add though that I wouldn't want to use these as my sole source of light, just supplemental, you simply can't see much and the colours are weird but early indications are that they can really make my plants grow.

Supplemental is what I wanted here. I already have a well lit tank but some shaded areas crop up when the plants grow in. I've managed to position these LED bars over my light demanding plants to give them a real test. This morning I did another simple test and turned them on 3 hrs before the rest of the lights, my ludwigia inclinata and rotala wallichi soon opened up with these lights on. I have two more bars that I can use, I might be able to stagger them so the light spread is very even. Pics soon, I promise.

[DarkCobra]

I will also be following this thread with interest.

Note that if you have minimal electronics skill, and more time than money, you could build identical LED clusters for a lot less.

If you don't feel like soldering dozens (or hundreds) of LEDs together, you can trade some money for time and use the big guns - 1W leds. SolarOasis says their clusters use less than 2W of power; most of the output is in red. So two 1W reds (2x $11 = $22) and a few standard blues (~$2) will exceed their cluster's output. Add a few more bucks for PVC enclosure, perfboard, resistors, etc. A laptop power supply ($10 surplus) can power lots of clusters. Still around 1/2 the price of their product per unit of light.

[TheOtherGeoff]

Some of those companies are making LEDS in up to 5watts now. they are getting hem to breach into the multi hunderd lumens but they are SOO expensive. i am definilty interested to see how they turn out. another thing to consider is the beam housing that the LED is in. is it a wide angle, narrow angle, projecter?? all these things are going to come into play with the led being effective or worthless

[Safado]

Originally Posted by DarkCobra

If you don't feel like soldering dozens (or hundreds) of LEDs together, you can trade some money for time and use the big guns - 1W leds. SolarOasis says their clusters use less than 2W of power; most of the output is in red. So two 1W reds (2x $11 = $22) and a few standard blues (~$2) will exceed their cluster's output. Add a few more bucks for PVC enclosure, perfboard, resistors, etc. A laptop power supply ($10 surplus) can power lots of clusters. Still around 1/2 the price of their product per unit of light.

I am seeing a great DIY project. Where can you find the 1W LEDs? How many volts do they use? What is the light output of a 1W LED? Would you use a resister, or wire them in series?

[DarkCobra]

Originally Posted by Safado

I am seeing a great DIY project. Where can you find the 1W LEDs? How many volts do they use? What is the light output of a 1W LED? Would you use a resister, or wire them in series?

I found 1W LEDs here. Found them last night for use in a non-aquarium related project. The manufacturer's spec sheets are linked and I recommend you read that for all the gory details.

Any wiring configuration will work as long as you don't exceed the maximum current for the LED.

Most large multi-LED illuminators are series/parallel. For example, if you have a 12v supply and want to drive 2.5v LEDs at maximum brightness, you'd string 4 LEDs together in series, along with a resistor to trim off the extra 2v. Add additional strings of LEDs/resistors as necessary. The resistor produces heat, so use one with appropriate wattage rating. If you're clever with your power supply and LED configuration, you could omit the resistor altogether and reduce heat/energy consumption; but the resistor also provides some protection to the rest of the string in case one LED shorts out.

[tazcrash69]

Originally Posted by Safado

I am seeing a great DIY project. Where can you find the 1W LEDs? How many volts do they use? What is the light output of a 1W LED? Would you use a resister, or wire them in series?

As any geek will tell you, you can find LEDs at Radio Shack (a Tandy Company).

[DarkCobra]

I am continuing the DIY discussion in a new thread to avoid cluttering this one further. Check it out if you're interested, I have some great new info:

http://www.plantedtank.net/forums/sh...825#post208825