DIY LEDs - The write-up
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lpsouth1978
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Here is a quick update on my latest LED build. I used a mix of XR-E cool white, XR-E royal blue, and XP-E royal blue LED's. This will be over my 3 gal pico build. The pictures are no great and it is not completed, but it is close. Let me know what you think.
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chrisfowler99
Premium Member
Trying to figure out what I'm going to run into trying to power my planned setup.
I'm looking at 216 Cree LEDs running through DWZM's DIY CAT4101 driver (plus some sort of arduino setup)
If I use multiple Meanwell SP-320-24 power supplies I'd be looking at 36 6-LED strings. If each string is approx. 1 amp, and the power supply is 13A, am I correct in thinking that I'm limited to about 12 strings per power supply, meaning I'll need three of them?
960W of LED...
I'm looking at 216 Cree LEDs running through DWZM's DIY CAT4101 driver (plus some sort of arduino setup)
If I use multiple Meanwell SP-320-24 power supplies I'd be looking at 36 6-LED strings. If each string is approx. 1 amp, and the power supply is 13A, am I correct in thinking that I'm limited to about 12 strings per power supply, meaning I'll need three of them?
960W of LED...
XSiVE
New member
As much as your info is appreciated, Im not sure if its within RC's user agreement since you represent a vendor, they might edit you.
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lpsouth- 24 LEDs over a 3g pico?! Thats crazy lol
lpsouth1978
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I know it's unconventional and a LITTLE overkill, but I like the custom lighting options with the dimmers and the ability to use it over a larger tank if desired.
sammy113
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yeah, I saw the pics and thought it was nicely done. Looks like I didn't read the 3G part lol
Thats insane. You better upgrade your tank to 20G cube or something close if you already spent that on LEDs :lol:
TheFishMan65
New member
chrisfowler99
You may need 4. IIRC kcress has always said only use about 80% of the power supply. It all depends on how hot it gets.
You may need 4. IIRC kcress has always said only use about 80% of the power supply. It all depends on how hot it gets.
chrisfowler99
Premium Member
Yeesh...four 320W power supplies...1280W.
To replace what would be, at most, 1200W of MH.
Makes me wonder if I'm thinking of using too many LEDs.
The tank is 84"x23" and 31" deep. I was thinking I would need a good number running 20-40 degree optics to hit the sandbed.
Just because your power supplies are able to put out 960w of power doesn't mean that you're driving your LED's with that much. With 216 LED's you'll be around (216 x ~3.2v x 1a) 691W, if driving at full force. If you drive it at 700ma, you'll be at around 480W. These are just rough numbers.
I wouldn't really worry about using 20-40 degree optics to hit the sandbed. 60,70,and 80 degree optics work just fine. Just to put your build in perspective, my 96"x36"x36" is going to be using 240 LEDs with 80degree optics. I plan on running them around 700ma, using about 600w.
kcress
New member
chrisfowler99; Don't forget that as a DIYer there is nothing stopping you from selectively lighting what you want/need lighted. You need about half the wattage for a full coverage like a MH setup when you switch to LED.
A DIYer could easily cut out another 20% just by not over lighting the tops of high rocks and not over lighting the bottom where nothing is supposed to be growing anyway. Your eye will have problems differentiating between x PAR and 2X PAR so visually it makes little difference placing less light on areas of the bottom that need no photon energy except for the viewer.
Don't forget that dim and bright areas create visual interest.
I'll be individually mounting every LED so I can put only the intensity/$$ needed, where it's needed. I'll build a string then install them one at a time.
A DIYer could easily cut out another 20% just by not over lighting the tops of high rocks and not over lighting the bottom where nothing is supposed to be growing anyway. Your eye will have problems differentiating between x PAR and 2X PAR so visually it makes little difference placing less light on areas of the bottom that need no photon energy except for the viewer.
Don't forget that dim and bright areas create visual interest.
I'll be individually mounting every LED so I can put only the intensity/$$ needed, where it's needed. I'll build a string then install them one at a time.
Reef_Matrix29
Water Lover
+1
That is A LOT of light over a pico tank, what distance are you elevating that "sun" and what are you keeping the the tank that needs that kind of output?
That is A LOT of light over a pico tank, what distance are you elevating that "sun" and what are you keeping the the tank that needs that kind of output?
chrisfowler99
Premium Member
True...I wouldn't be pulling 100% of the power. I was thinking 3.7v instead of 3.2.
I need to read a bit more about running at 700ma versus 1a. It seem to recall reading a lot of people driving the cool white LEDs at 1a and the Royal Blues at 700ma. I haven't dug into why yet.
More research!!!
Taqpol
New member
In general it seems people like more blue as opposed to more white, so the people that run differential current probably run 0.7A on the whites and 1A on the Blues. For the record, some of CREE's more obscure LEDs that are starting to come into popularity (the Red, and even the Neutral White, I think) can only take 700mA as their max current. Since it is not easy to adjust the current on my CAT4101 drivers I ended up driving all of my LEDs at 700mA and I like the color.
Penetrance is always the problem with deep tanks, but like I said in the other thread I think if you go with six 24 emitter fixtures for 144 total LEDs, you should be able to mix 40 degree optics in the center with 80 degree or no optics near the edges to smooth out the coverage. Though as Kcress said, our eyes are really bad at detecting pretty substantial differences in intensity after a certain point, so while tuning your optic usage it might be really good to have a PAR meter to make sure you aren't going to be "burning" any corals near the top of your tank.
TenKreefer
New member
Hey guys, I have two of these drivers laying around from some old http://uk.farnell.com/lightech/901060024p/led-60w-dc-24v-al-housing-converter/dp/1797609
It looks like they're constant voltage, not constant current. Can they safely be used to power some HP LED's?
It looks like they're constant voltage, not constant current. Can they safely be used to power some HP LED's?
chrisfowler99
Premium Member
Yeah...your post in the other thread has me thinking...though I'm still paranoid about the possibility of building a whole rig and then finding out I've built something not strong enough. If it's too strong it's easy to dim. If it's not strong enough... :eek1:
I'm starting to wonder if I can fit 30 LEDs on the heatsink that you're using (or maybe bump up to the 12" length one) and run 180 total. Just to be safe.
At 144 LEDs I'd be running 24 strings of 6 LEDs. At 700ma I should be able to run 12 strings per SP-320-24 power supply, totalling 9.4a...so under the 80% threshold. And well under 640 watts.
At 180 LEDs I'd be running 30 strings of 6 LEDs, which would mean, even at 700ma I'd have to run three power supplies with 10 strings each...
Ugh...beating my head against the wall! :reading:
One other (possibly really stupid) question. I'm thinking of having a couple of dedicated 20a outlets installed. Would two power supplies pulling 9.4a each basically fill an outlet? :worried:
TheFishMan65
New member
tenkreeefer,
Theoretically you could use a resistor in series. It depends on how much variation in voltage they have. Output is listed at 24-26.4, but I can't find if it can or does swing beyond that. It might run 2-3 string of 6-7 LEDs. Where you will get in trouble is if one of the LEDs in your series shorts the voltage drop will decrease and the current increase and may fry the whole string. A fuse could help.
Theoretically you could use a resistor in series. It depends on how much variation in voltage they have. Output is listed at 24-26.4, but I can't find if it can or does swing beyond that. It might run 2-3 string of 6-7 LEDs. Where you will get in trouble is if one of the LEDs in your series shorts the voltage drop will decrease and the current increase and may fry the whole string. A fuse could help.
TheFishMan65
New member
chris ,
Two 9 amps power supplies would eat your circuit up. However, they are probably drawing closer to 2 amps. 9 amps at 24 volts is 216 watts. 216 watts at 120 volts is 1.8 amps. Add in some inefficiencies (80%) and you are at 2.25 amps. Just because it supplies 9 amps at 24 volts does not mean it draw 9 amps from the wall. It could, but would only be about 20% efficient.
Two 9 amps power supplies would eat your circuit up. However, they are probably drawing closer to 2 amps. 9 amps at 24 volts is 216 watts. 216 watts at 120 volts is 1.8 amps. Add in some inefficiencies (80%) and you are at 2.25 amps. Just because it supplies 9 amps at 24 volts does not mean it draw 9 amps from the wall. It could, but would only be about 20% efficient.
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