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03/11/2009, 11:30 PM | #251 |
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I've been following this thread and you have sparked an interest in going LED.... I would also like to say that I think that what soundwave has done is great but the constructive criticism from lynxvs is only to take from soundwaves design and improve on it to make it more efficient, that is how we move forward in this hobby.
So what I’m saying is keep the ideas coming!!
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03/12/2009, 07:50 AM | #252 | |
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From my experience 48 LEDs for a 48" tank would not provide enough light. I have to say I have not used the CREE I use Luxeon Rebels but they are almost identiticle. In my tank which is 30" in length I have 60 LEDs. Without optics I am reading just slightly higher PAR then what soundwave is reading.... |
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03/12/2009, 08:14 AM | #253 | |
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1. I can't say I don't believe them because I wasn't there to see them taken....they don't seem unreasonable... it's just the fact that he is getting about the same PAR as me with half the LEDs and a larger tank that bothers me. 2. You can tell how the driver is working from the picture? 3. No you can run it without the fan with that big heatsink.... I was just suggesting mounting the fan so the air flows through the fins for maximum cooling. 4. That's what the data sheet says...... in the real world it's a little different. I bet soundwave has had a LED failure in the first couple of days of operation. 5. It also results in lower PAR. If you like the fixture on top of the tank this is fine but if you raise it up you need optics period. |
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03/12/2009, 08:36 AM | #254 | |
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I guess some people are having a problem with the word "flawed" , OK , OK I will call them "engineering changes" . I did post a build here several times a while back and if you click on my website you would see my build..... athough the information is outdated now I have had many engineering changes to it since. I was hoping for lots of feedback on this but received little. Might be the reason I try to give more comments on soundwaves design. |
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03/12/2009, 08:39 AM | #255 | |
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03/12/2009, 08:50 AM | #256 | |
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i'm planning a 8 footer. ( 96 x 16 x 16.) |
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03/12/2009, 08:55 AM | #257 | |
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03/12/2009, 08:58 AM | #258 |
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I am interested in hearing more about the distance the LEDs are mounted from the water surface in relation to using or not using optics.
Soundwave what is the distance from your LEDs to the water surface and the same for Lynxvs? I am planing builds for my two nanos and right now my PC light is about 2.25 inches off the surface. |
03/12/2009, 09:03 AM | #259 | |
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www.photiczoneled.com |
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03/12/2009, 09:37 AM | #260 |
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lynxvs, look up "impingement jet" or "impinging jet", that is the basic configuration that soundwaves fans have with the heatsinks and it is a very effective method of heat transfer.
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03/12/2009, 09:45 AM | #261 | |
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As you probably know optics will concentrate the output of the light source into a narrow beam so the light intensity is greater farther away but with a narrower beam. Of course this reduces the "spread" of the light to what soundwave calls the "spotlight effect" There is something else going on when light strikes the surface of the water called "Snells Law" what this means is light will be refracted or bends when it hits the surface of the water so it works sort of like a lens but not as good. This is only true when the light source is very close to the water. The ideal distance could be calculated I assume. If you use optics you can raise the light and depending on the width of the beam have the same or greater light intensity with the same light spread. Remember even though you have a narrow beam the light will spread the higher you raise it. I have tried hanging the light at 6" , 10" with optics and 2" without optics. |
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03/12/2009, 09:55 AM | #262 | |
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03/12/2009, 10:03 AM | #263 |
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My fixture is 4 inches above the tank with another inch or so to the water. To lynxvs, the fans push air downward which allows air to flow through and out of the fins.
I've given it some thought an would like an opinion on this. I could add optics to the design but I would have to raise the fixture. So the thought is what if I cut a hole in the canopy for the LEDs and attached the entire fixture to the top of the canopy? I would think this would allow for more spread while using optics and allow the heatsinks to operate more efficiently as they would be pulling outside air instead of recirculating the air inside the canopy. Any thoughts? |
03/12/2009, 10:07 AM | #264 |
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heres a link i pulled off google, i didnt really read it but you can probably get the idea from the pics.
http://ieeexplore.ieee.org/ielx5/614...number=1362805
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03/12/2009, 10:08 AM | #265 |
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So would the consensus be that if the LEDs will be mounted close to the water surface, in the rage of 2 inches that optics should or do not need to be used?
Also with the Nanos they are frequently much shallower than larger tanks, for example one of mine is 8 inches another 15 inches so the depth the light needs to penetrate to reach the bottom is much less maybe not requiring the optic focused beam? |
03/12/2009, 10:31 AM | #266 | |
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03/12/2009, 02:23 PM | #267 |
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lynxvs or Soundwave so what does your mind recommend number of LEDS with optics per 24"
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03/12/2009, 03:28 PM | #268 | |
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03/12/2009, 04:18 PM | #269 |
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Don't the LED without optics give you the MH look anyway?
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03/12/2009, 04:42 PM | #270 |
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LEDs are a point source with or without optics.
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03/12/2009, 05:08 PM | #271 |
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OK the decision has been made. I will be modifying the canopy and fixture this weekend. I will order the optics in a few minutes. The idea here is to cut a hole in the canopy roof about 9x36. I will build an enclosure for the LED fixture tomorrow and attach that to the top of the canopy. This will raise the fixture about 12" off the water surface which should still give me a decent spread with the optics along with making it brighter. Cooler room air will be drawn into the heatsinks instead of warm tank air. I'll post pics.
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03/12/2009, 05:09 PM | #272 |
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Cool, looking forward to the pics!
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03/12/2009, 05:19 PM | #273 |
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Here's a wiring question:
If an LED has a Vf of 3.6v, and you are using a BuckPuck with 24 VDC input, then this is just barely enough to power 6 of these LEDs in series; the Vf of 6 LEDs would be 21.6v (need 2v margin). Could you wire two groups of 6 (in series) in parallel?? Basically after each group of 6 the wiring would connect back at the buckpuck essentially making two parallel groups of 6. Anybody know if this will work? And if so, why don't we use more parallel wiring to power more LEDs with the Buckpucks? Thanks
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03/12/2009, 05:32 PM | #274 | |
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Thanx for the thought! |
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03/12/2009, 05:47 PM | #275 |
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one more question thats probably been covered
Is it ok to mix LEDs of different Vf in the same series if they require the same current? Ie a few cool white 3.85 Vf, 700mA LEDs mixed with some 3.15 Vf, 700mA LEDs.
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- Ryan B "that is enough skimmate to ruin lives." - GSMguy Current Tank Info: 220g Display, 70g sump, 35g frag, 50g fuge, 2x250w MH, 1x400w MH, 2x80w T5, 2x140w VHO Actinic |
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