DIY LED Demo presentation: Questions and Answers

reefs4life

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I was wondering if someone can tell me what LED was talked about at the swap that gives 100% spread without a lens. Was it xp-g crees and then use xr-e crees for blue? also... Has anyone used a meanwell lpc-20-700 to drive leds? It also consumes 21w and has an output of 30v. Anyone know if it will be ok to run 9 3w crees on these drivers?


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reefs4life

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camanuch said:
Y not use 60-48 drivers. Also I only use xr-e inless its a deep tank.
Because I want to run 2-18 LED on 5.9x9 heatsinks for every 24" length of my tank, each board needs a driver for blue and white so i can turn them on and off independently. To run a 60w driver on 9 LEDs seems to kill the whole point of saving energy especially if I'm using 12 drivers. 12X21w(lpc-20-700)=252w total consumption. 12X60w(60-48)=720w total consumption. My current setup 3x250w mh 750w consumption plus 4 hours 6x65w pcs=390w. I don't mean this in a bad way but I just feel that some people forget that a point of LEDs is energy reduction but with the use of some drivers you don't achieve that


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ming

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Because I want to run 2-18 LED on 5.9x9 heatsinks for every 24" length of my tank, each board needs a driver for blue and white so i can turn them on and off independently. To run a 60w driver on 9 LEDs seems to kill the whole point of saving energy especially if I'm using 12 drivers. 12X21w(lpc-20-700)=252w total consumption. 12X60w(60-48)=720w total consumption. My current setup 3x250w mh 750w consumption plus 4 hours 6x65w pcs=390w. I don't mean this in a bad way but I just feel that some people forget that a point of LEDs is energy reduction but with the use of some drivers you don't achieve that


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The wattage is the maximum load the drivers can handle. If you run fewer LED's, its going to use less wattage.
 

ming

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I was wondering if someone can tell me what LED was talked about at the swap that gives 100% spread without a lens. Was it xp-g crees and then use xr-e crees for blue? also... Has anyone used a meanwell lpc-20-700 to drive leds? It also consumes 21w and has an output of 30v. Anyone know if it will be ok to run 9 3w crees on these drivers?


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A quick look at the lpc-20-700 seems like it could run 8 LED's more safely. 9 seems like you're pushing it too much
 

tosiek

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I didn't go over electric costs at all because your not actually saving electric going 3W LEDS and building your lighting to match MH setups. Its minimal at best, and I think I remember Sanjay talk about that during his LED presentation at Pratt.

Im going to do the number crunching but energy consumption with the XP-G's or XR-E's evens out when comparing it to MH's. I heard a few people talk about it recently that your not saving much if at all, and with certain setups spending a little more going LED's to get sufficient light for your reef tank. In theory, when spacing out the LED's, "enough" light for your tank your saving money, but "enough" light just keeps easier coral alive. You are saving money going 1W LED's which is pretty much the only thing that was used a year ago. 3W LED's were far and few between in usable spectrums for reef tanks. Any store bought LED fixture can still say "savings on electric" because they are under driving their 3W LED's so performance isn't up to par with the DIY fixtures.

But, you are saving yourself about 70-100$ every 6 months per MH bulb over your tank. Changing out all my bulbs every year costs me 500$, for you with 3x MH and suppliments around 700$.

This holds true until you start using the MC-E bulbs. You can use less and cover more area with a brighter light per inch than the other bulbs. Thus the Savings starts to come back. Its minimal at best but its something.
 

tosiek

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You can push them at 3-4" without lenses and get the same coverage and depth as the other LED's spaced at 2" with 80 degree lenses. I'm still looking around for a good post or article on lense spreads or something. Can't find anything yet. Personally, with my minimal LED experience, i would stay away from not using lenses if your supplying usable light to deeper 20" tanks. Everyone I spoke with guided me that way and stated that your just not delivering usable light in the par needed that far down until you use lenses.

Here is the Data Sheet for the MC-E's btw.

As far as the LPC-20, 9 would be more than fine. Its not really pushing it but Ming likes to play it safe.
 

ming

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Actually, I think you get more savings then that on your electric bill. I was using almost 700W of T5 lighting on 9.5 Sq Ft of tank, and now I'm using ~200W (when dimmed to 60%) of LED's on my new tank which is 10.5 Sq Ft. I tested with my PAR meter and @ ~200W, it is equal to my T5 lighting. I'm slowly increasing the intensity, so the wattage is slowly going up as well, should be slightly over 300W at max power with a higher PAR.

Typically the LED's are calculated roughly 3.3V each, as a safety precaution, you don't want to use 100% of the max volt, the same reason why you don't want to load your outlets at the maximum volts on your circuit breaker. You might get too close to putting too much power through the wires and they start getting real hot...
 

Deep Dive Coral

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Actually, I think you get more savings then that on your electric bill. I was using almost 700W of T5 lighting on 9.5 Sq Ft of tank, and now I'm using ~200W (when dimmed to 60%) of LED's on my new tank which is 10.5 Sq Ft. I tested with my PAR meter and @ ~200W, it is equal to my T5 lighting. I'm slowly increasing the intensity, so the wattage is slowly going up as well, should be slightly over 300W at max power with a higher PAR.

Typically the LED's are calculated roughly 3.3V each, as a safety precaution, you don't want to use 100% of the max volt, the same reason why you don't want to load your outlets at the maximum volts on your circuit breaker. You might get too close to putting too much power through the wires and they start getting real hot...

+1... im going from 1400w to let's say 400. And that is over calculating and at max push. Ming I was wondering if I could borrow your par meter. When I go to change my light.?
 

reefs4life

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ok here goes another question. If I get a 72" by 10" heatsink what would be the best way to mount LEDs on it? I don't think I would want to try to drill and tap it because one mistake and there goes the whole thing. Also, how many LEDs would I need to mount on it for a 210 with dimensions, 72" by 24" by 29" (LxWxH)
 

qy7400

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ok here goes another question. If I get a 72" by 10" heatsink what would be the best way to mount LEDs on it? I don't think I would want to try to drill and tap it because one mistake and there goes the whole thing. Also, how many LEDs would I need to mount on it for a 210 with dimensions, 72" by 24" by 29" (LxWxH)



If you go back to the start of the thread tosiek has a link to Reef LED and the eval they did, the fixture the tested was a 60 3W LED that drew under 200 watts with PAR well over 150 not just at 24? but offset 12?. Right from the start your cutting the power use in half and saving on bulbs every year. I would build more module though, instead of 1 huge heat sink go with 6 6x18; it?ll probably be cheaper plus if you need to service part of the light you can without shutting the whole system. If you feel you need more light you can move modules around to add more a lot easier than relocating/soldering LEDs. You can use the thermal paste that comes with the Rapid kits vs. tap/drill, only downside is replacing a single LED would pose a small challenge.
 

BZOFIQ

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ok here goes another question. If I get a 72" by 10" heatsink what would be the best way to mount LEDs on it? I don't think I would want to try to drill and tap it because one mistake and there goes the whole thing. Also, how many LEDs would I need to mount on it for a 210 with dimensions, 72" by 24" by 29" (LxWxH)

"Measure twice, cut once" comes to mind. Measure everything carefully before drilling then mark it all down on the aluminum before drilling and tapping holes. Once you have everything transferred with a marker you can see if you screwed up anywhere. If you did you can just wipe it with alcohol or a very fine sand paper and start over. Drill and tap once you're sure that this is what you want.

If you did screw up with few holes here and there it is not a biggie, you can just drill next to it and use those holes to mount LEDs, you'll just end up with extra holes and while they may not be aesthetically pleasing they wont affect functionality of the fixture.

Best thing to do before you even start on a one-piece 6-foot fixture is to grab some old pieces of aluminum or an aluminum heatsink from a PC and drill and tap some holes as an excercise. You don't have to be a rocket scientist to get it done right. Little practice is all that is needed.
 

wld1783

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LEDs will definitely lower you electric costs with a standard tank. A 60 LED fixture driven around 750mA will produce over 400 PAR with the right optics at 24" and use under 200 Watts

70 Degree Optics

Driver Input........PAR@24?........PAR@24?........Watts
Volts DC...........Center Mass...Center + 12?

9........................432...............170.... ............186
7.5.....................348...............158..... ...........162
6........................301...............140.... ............124
4.5.....................262...............95...... ............84
3........................171...............65..... .............49
1.5.....................74.................30..... .............21

Here is a pic of the fixture.

Optics70ON.jpg


The downside is the coverage is around 36"x24"

I still use a 400 watt MH over a 72" 440Gal tub and a single bulb on an electronic ballast worked well. To cover the same area I had to go with 120 LEDs on two heatsinks. The electrical savings in this case is less but where I did see that the savings were in the grey or covert costs of running MH...Heat.

I no longer spend $ keeping my tank cool. To be as efficient as possible I run the MH from Halloween to the Ides of March to heat my sump room. I then swap out the fixture and run LEDs the rest of the year. This is easy as this is in my sump room and access is as easy as changing a bulb.

I know this is an extreme example but it does highlight the advantages of LED vs MH and works quite well for me.

Bill
 


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