DIY led lighting - have I got it right before purchasing
great forum. I think i've interpreted everything right so
this post is more for clarification before purchase then anything.
i'm a freshy with planted tanks and native australian fish, I've decided to start updating my fluros to LEDs.
my trial tank is 1200x450x700 (47x17x27) - 378L (108g)
here is what I'm planning;
heatsink- makers 36in - great product, well done
LEDs- Cree 14x 3up(2rb/1nw) 40 deg optics
Cree 8x 3up(3cw) 40 deg optics
exotic 3x hv 60 deg optics
exotic 3x dr 60 deg optics
? 3x cb 120 deg optics
power supply - 12v 6a - I'll source local so I don't need an adaptor
- query - as long as I cover the required current with
1a buffer. I don't need to worry about VAC
drivers- inventronics 1x 25w/700ma
inventronics 1x 40w/450ma
inventronics 5x 40w/700ma
controller - dim4 sunrise/sunset - query- is there a limit to the number of
drivers I can connect per channel
relays - 2x relays & sockets to run fans
now for the led setup
ch1- 2x (40w/700ma---4x 3up(2rb/1nw))
ch2- 40w/450ma---3x hv, 3x dr, 2x 3 up(2rb/1nw)
ch3- 3x (40w/700ma--- 4x 3up(3cw)
ch4- 25w/700ma---2x cb
i've chosen the channels to give me control over whites, blue/whites, colours &
from my calculations this should be much more than needed for plant growth, but I'd rather have more and be able to dim ( & leave the opportunity open to become a reefy with the addition of a few LEDs and some salt)
please let me know if I've done anything stupid
I'd appreciate any comments or thoughts
You sure you got enough LED lighting to grow plants with that? From what I can tell you got the equivalent of 18 cw/nw Cree LEDs total in your lighting (not sure what the 3x hv and 3x dr are).
Also, have you checked the geometry on your light array? How high are you planning to mount the lighting? 40 degree optics makes for a pretty narrow beam.
thanks for your input
14 x 3up(2rb/1nw) = 28rb & 14nw LEDs
8 x 3up(3cw) = 24cw LEDs
total of 28 royal blue, 14 neutral white & 24 cool white.
I'm hoping this blend will give me a nice full spectrum about 10000-14000Ks (not that kelvins mean anything to plant growth) I shouldn't need any more blue as I don't have coral.
I've added hyper violet (hv) k deep red (dr) to try and mimic PAR wavelength peaks
my tank is 32in high so even if i have the lights directly on the tank top it would be 2.5 feet from the substrate. my light will be suspended about 1 foot from the top of the tank. the 40 deg optics will give good penetration getting usable light to the bottom.
You might actually have too much blue light in that tank XD. What overall color temp are you looking for? I know color temp doesn't really matter for plant growth, but it does matter for our own aesthetics =]
From personal experience I've seen 5 cw to 1 blue ratios work out very well. The website buildmyled.com also uses this ratio for their showtank lights (though I've never actually purchased their lights before). You might want to buy some extra LEDs and experiment with the color mix when you hvae them on hand.
If you buy LEDs from china via ebay you can get 10/50/100 pack sets of LEDs for real cheap. Not as high quality as CREEs but totally worth the value IMO if you make your fixture flexible. My brother uses them extensively and has no complaints. I've read though that cheaper LEDs have issues with their color temps deterioriating over time whereas the CREEs have a guarantee that their light intensity and color temp will remain at a certain % of specifications after a period of time. The LEDs online are 1/8 of the cost ($0.80 vs $4.00) so I can't really complain (though you have to wait 2 to 4 weeks for them sometimes).
I'll do a little digging on the ratios.
I've written down in my notes that 1rb:1cw = 10000-12000k ( I haven't noted where I got that info from).
the addition of the extra cool whites (5000-8300k) should soften the effect. can anyone confirm if I've got this right?
I'll have a look at the cheap LEDs. from my understanding the crees put out more light using less energy ( thus meaning less driving power for each string or more LEDs)
as well as what you mentioned with the accurate wavelength peaks. if the led peaks at the wrong wavelength then it potentially could be useless to plants become purely mood lighting ( eg red (670nm) and far red (730nm which is outside PAR).
the app looks useful. cheers mate.
unfortunately i can't drop the LEDs onto the strip using my I-pad.
this means I'll have to venture upstairs to the civilised part of the house :)
i'm worried that it doesn't give a kelvin rating after adding blues.
while not being a factor in plant growth directly, kelvins is an important factor to penetration.
6500k at the surface means far less at the substrate.
for mid and cover plants apparently 8000k-10000k is needed.
most data out there is for a 24 in tank. all I can find is that if you have a deeper tank have more kelvins.
reefers need 14000k+ due to the fact that they need to replicate light conditions that are natural at many meters deep for coral growth.
Your a bit mistaken on the blue part for planted tanks. Blue light does penetrate the most but planted tanks need full spectrum all the way to the substrate.
thanks for doing that steve
there seems to be a lot of yellow and green in the spectrum (wasted energy?)
i'm still concerned with the kelvins ( in regards to penetration)
"It is also noteworthy that many "terrestrial plant lights" as well as many aquarium plant lights (often are lower in kelvin temperature) have more "red nanometer spikes" than higher kelvin 6500k, 10,000k & higher lamps.
The problem with these lights is that while all plants utilizing photosynthesis require the same essential ABCs of PAR (see the PAR section), the facts of light energy penetrating water requires higher kelvin (6500k +) be added to provide maximum PUR (see Useful light energy/PUR section). Aquatic Plants and corals have adapted/evolved to the natural light energy at certain depth of water and the misguided attempt to adapt these terrestrial plant lights is not going to be 100% effective as a light with more water penetrating blue & slightly lower red nm energy."
aquarium lighting by carl strohmeyer
I,m starting to think about adding some reds in strategic locations about the substrate
[Ebay Link Removed]
If you look at the specs for the Cree XP-G's their 5W LEDs generate 260 lumens at 700mA.
Anyone know how to calculate the lumens per watts for these? Will a 5W Cree really run at 5W if you're only running at 700mA instead of it's max 1.5A?
From back in my high school days, P=IV so Power = Current * Voltage. I'm assuming that the voltage doesn't change for these guys so if you decrease current the power (wattage) should decrease proportionally.
> So the power consumption of a 5W Cree running at 700mA is closer to 2.3W.
> Which means the lumens per watt is ~113
> Whereas the lumens per watt of these "high-power" Chinese LEDs are ~60 (180lumens/3W)
> Which means the efficiency of the Crees is almost 2x!
Does that make sense???
Having greens and yellows can be argued to be "wasted" light because they don't aid in photosynthesis, but the more green and yellow light you send into the aquarium, the more those colors will shine off your plants and into your eyes.
I would be careful about having too many red likghts. I read somewhere (I think in the lighting sticky) that algae is better at utilizing red than blue light, so having high levels of red light without proper plant load could be conducive to algae blooms, etc.
More food for thought! Let us know what you're planning.
If I end up having more free time I might start up a thread documenting my DIY lighting for my DoAqua 90P tank. I just got my makersled fixtures and am waiting on my LEDs from China =]
that's some real food for thought ced
I was just reading the red spectrum causing algae. also plants (and coral) have adapted to their natural depth which means that too much red can be detrimental.
i understand what you're saying about the visual aspect of the yellows and greens.
it still amazes me that the colour things appear is the colour they're not.
i think i'll stay with my reef capable amount of blues but play with my wiring so that blues, whites, pur colours and aesthetic colours can be controlled and dimmed separately. thus i can have whatever temp/spectrum i need.
what i love about the diy led approach is that if i think i'm short of red or whatever i can just add a couple of LEDs and problem solved.
i haven't ordered yet but i shouldn't be far off. just finalizing some details.
let us know how your build goes. are you using dimmers?
Concerning Lumens per watt. First of all, you need to compare apples to apples when comparing LEDs. LED manufacturers don't have a consistent method to publishing these numbers, so you need to dig into the spec sheets. Most companies publish this metric by flashing the LEDs with a 20 millisecond pulse of electricity. The LEDs are ‘cold’, so they are very efficient during the test. If you would test that same LED 10 seconds later, it would produce a lower Lumen number, since LEDs produce less light as they heat up. If you would test that same LED after it has been sitting over an aquarium for three hours, you would have an even lower number. While on this topic, it is important to note there can be significant losses with the optical and electrical systems in any lighting system. By the time you consider all three levels of losses (thermal, optical and electrical), the overall fixture efficiency is nowhere near the values published for the bare LED.
Concerning the green/yellow light, wasted energy issue. In summary, this is the worst myth on the Internet concerning horticulture lighting and photobiology. As long as photons between 400 and 700nm are absorbed, they are useful for photosynthesis. There are no wasted wavelengths in this band of light (electromagnetic radiation). Here is how the myth is usually propogated: “Plants are green, so they are reflecting the green light back to your eye, so the plants are not using it. Hence, green light is wasted energy. “ Scientifically, this is absolutely wrong. Green light is very useful to plants, it just doesn’t get absorbed by the chloroplasts as efficiently as blue and red light. Hence, the plant appears green. However, it is not reflecting all of the green light, and green light even has some advantages over red and blue light. Green light (and far red light) can penetrate deeper into the plant canopy, so spectra with green light usually outperform spectra that only contain red and blue light. In fact, NASA published a paper concerning this issue in 2004, and the green-enhanced light actually grew 45% more biomass than the red and blue spectra.
Finally, Kelvin is basically a useless metric for comparing different light sources, as it does not define a single color. In other words, you can buy a 5700K light from 20 different companies, and they will all look different, even though they are all correctly labeled 5700K. Google the 1931 CIE color chromaticity diagram, and you will see vertical black lines near the center of the chart. These vertical lines define the specific color temperatures (i.e. 5700K), and you will notice how they stretch from the pink region into the green region. That is why you will see so much variation while comparing lights based on the Kelvin scale. Alternatively, I recommend you look at the actual spectrum of light, as this is what is used to calculate the Kelvin temperature. By looking at the spectrum power distribution (SPD) chart, you will be in a much better position to compare various light sources for horticulture applications.
I hope this helps ‘shed some light’ on the subject on LEDs and horticulture lighting. This wasn’t meant to be a comprehensive dissertation on the above topics, but I wanted to chime to add my two cents to the discussion :-)
great info Nick
thanks for sharing your expertise
|All times are GMT. The time now is 12:25 AM.|
Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.