DIY LEDs - The write-up

[ReefEnabler]

Very cool!
Being 250ma seems difficult to drive. Do any meanwells have that output?

Would you guys feel safe putting that on a 350ma buckpuck and installing a 3.5kohm resistor between ref and ctrl?

 

[widmer]

Yea from my perspective, the rated voltage/current is a huge downfall... I mean, if there is in fact a power supply/driver which is well-equipped and cost effective to drive it, I'm not aware.

They require 26 volts, and the fact that buck pucks max out at 48v means that a person could only do one per LED unless they want to drive the LEDs in parallel..

A meanwell could be used, but again it would have to be one per LED unless two were run in parallel...

So it's a fun idea because its such a large amount of light in such a small package, and the cost per lumens is really pretty decent, but as far as application they're not so great after all as far as I know. It does make me wonder why they designed it to be such voltage/amperage spec...

 

[ReefEnabler]

Now that I think about it, their numbers don't really make sense.

26v@250ma is 6.5 watts. If they are putting out 1500 lumens thats over 230 lumens per watt...

 

[ReefEnabler]

nevermind, from reading the datasheet it appears there are 3 separate strings of LEDs, for a total of 19.9 watts. That puts this around the 75 lm/watt range, which is like using a bunch of low-bin XR-E's. Nice shimmer though

 

[der_wille_zur_macht]

Thanks bud. How many of the meanwell drivers would I need for 36 LEDs?

Three, more or less. The "favorites" are the LPC-35-700 which is non-dimmable, 700mA, 48v max. Or, the ELN-60-48 (-P or -D) which is dimmable, 700 - 1300mA max current, 48v max. The LPC's are cheaper and if you don't want dimming, that's the way to go, as they're easier to set up, too.

nevermind, from reading the datasheet it appears there are 3 separate strings of LEDs, for a total of 19.9 watts. That puts this around the 75 lm/watt range, which is like using a bunch of low-bin XR-E's. Nice shimmer though

Very wrong color temp too, though I suppose you could "compensate" by adding a ton of blues and royal blues.

 

[dnahas]

So I have decided to make the switch to LED lighting for my system. I want to do it right the first time, so begins the process of figuring out what I want, and I need some help here.
After reading several pages from different posts I am still confused in just selecting the LED, the last few post are not helping. My assumption is that the Cree XP-G is the most efficient “white” light source and they are only readily available through cutter, is this correct?
If so the confusion only grows.

Cutter has the following R5 Bin’s available:
XPGWHT-L1-1B0-R5-0-01
XPGWHT-L1-1C0-R5-0-01
XPGWHT-L1-1A0-R5-0-01

Assuming the difference in these bin are the color temperature, I can’t figure out what bin is the correct for our use. Yes I am looking at the Binning and Labeling PDF from Cree, but I am not getting it.

 

[der_wille_zur_macht]

So I have decided to make the switch to LED lighting for my system. I want to do it right the first time, so begins the process of figuring out what I want, and I need some help here.
After reading several pages from different posts I am still confused in just selecting the LED, the last few post are not helping. My assumption is that the Cree XP-G is the most efficient "œwhite" light source and they are only readily available through cutter, is this correct?
If so the confusion only grows.

Cutter has the following R5 Bin's available:
XPGWHT-L1-1B0-R5-0-01
XPGWHT-L1-1C0-R5-0-01
XPGWHT-L1-1A0-R5-0-01

Assuming the difference in these bin are the color temperature, I can't figure out what bin is the correct for our use. Yes I am looking at the Binning and Labeling PDF from Cree, but I am not getting it.

You are correct, the XP-G is currently the "best" white LED for our purposes. As far as color bin, here's something I wrote on the subject a few days ago:

For the R5 brightness bin, Cutter has 1A, 1B, and 1C color bins. 1A is right on the BBL and farthest to the blue end, so it'll be the least yellow.

Though, 1B will also be just as much "not yellow" but having a really small blue-green tint instead of pure blue. 1C is going to be a little yellower and a little greener, so it's probably not worth considering.

For the R4 brightness bin, they have OD which is also right on the BBL but one step bluer than the 1A bin available with R5 brightness.

So, if you were on a budget, I'd get the R4 OD, because it's fairly blue, and almost as efficient as an R5. If you want the best, I'd get the R5 1A, since it's almost as blue, but brighter.

In the end, the variations in color between their bins are all fairly small.

It's tough to discuss in comparison with other types of lighting, because typically we rate lighting on the kelvin scale, which is a 1-d line through a 3-d space, if that makes sense. Meanwhile, Cree bins the white LEDs on the CIE1931 color space, which is a 2-d slice. The BBL (black body line) that represents the Kelvin scale happens to cut right through the middle of the area that Cree's color bins describe, so you can sort of correlate, but the BBL doesn't account for certain color changes that CIE1931 does.

For instance, the 1B and 1A color bins would get the same kelvin rating, but they're definitely not the same color - 1A is pretty pure blue-white, but 1B has a tiny hint of green.

If you're sticking with their R5 offerings, and don't mind paying the price, the 1A bin is probably the most desirable for most people, since it's neutral with respect to the BBL but skewed as far towards the blue end of the spectrum as any of Cutter's cool white XP-Gs. Mind, it's not exactly "blue" light, but at least it's skewed in that direction.

 

[der_wille_zur_macht]

Oh, and since you're considering XP-G for the whites, I'm assuming you'll use XR-E or XP-E for royal blues. Most people do a 50:50 split of cool white and royal blue, but since you're using the brighter XP-E you might want to consider something a little more skewed towards blue, i.e. 40:60.

 

[dnahas]

... Most people do a 50:50 split of cool white and royal blue, but since you're using the brighter XP-E you might want to consider something a little more skewed towards blue, i.e. 40:60.

Thanks for the fast reply,I was searching for that post as you re posted for me!

To confirm that would be the XPEROY-L1-D40-16-0-01?

I understand and agree with the 60/40 split, but the OCD in my does not like the layout. My "plan" was for 24 lights each fixture with two fixtures over a 4'x2'(120g) foot print. I also agree with staggering the white and blue, but again OCD is kicking in.

My next thought was to run 28 LED's per fixture (more always sounds better ) or run 50/50 mix and dimm the whites down to balance the color. Any suggestions?

 

[TheFishMan65]

I know we can't trust the math

I know we can't trust the math

We have (I think) just taken 2 inch spacing as a good idea. This may give a better idea for spacing. I will just throw it out there and you can laugh at me :lolspin:

Lens tend to spread the light in a triangle, it is not a perfect triangle. But if it was (go ahead laugh). If you calculated the spread (at the tank bottom) of your lens and started the next lens right where the first left off. Then you would have even illumination at the bottom (not quite true since the edges are dimmer - laugh again). So lets say the spread is 20 inches. LED1 is at 10 inches and LED2 at 20.

inches......0....1.....2.....3.....4.....5.....6.....7.....8.....9....10....11....12....13....14....15....16
LED1 Light..0%..10%...20%...30%...40%...50%...60%...70%...80%...90%..100%...90%...80%...70%...60%...50%...40%
LED1 Light..0%...0%....0%....0%....0%....0%....0%....0%....0%....0%....0%...10%...20%...30%...40%...50%...60%
Total Light.0%..10%...20%...30%...40%...50%...60%...70%...80%...90%..100%..100%..100%..100%..100%..100%..100%

Want twice the light at the bottom place them at 5 inches.

Now calculate the spread at the stop of the tank. Lets say 5 inches. In this case if you do the same triangles you will see a nice even distribution of the light. At five inches nice even triangles, but 2 inches gives us a problem. Good at the bottom, but jagged at the top. So by trying to find a number that divides into both the top and bottom spread (in this case 10, 5, 2.5, 1.25) you will get more ven light at top and bottom. Worried more about the center just use it.

If you are really worried as well as doing top and bottom you could calculate at 1/2 way point, or 1/3 and 2/3 as well.

This may explain why some people report light banding and others don't. It is a function of how high the light is above the tank and how deep the tank is.

I realize this is not perfect (laugh), but it may allow for people to achieve a more uniform light level - if that is what they want.

Got all that? :hmm4:

 

[TheFishMan65]

dnahas

I think you will need more than 48 lights. I think the minimum would be about 60.

 

[akindbro4u]

does 96 sound about right for a 60x24?

 

[TheFishMan65]

If I remember they (the experts) are saying 1 LED for evry 10-20 square inches of surface. So 96 is a good number,

 

[HeneryH]

Pardon the posts without reading all the way through this thread but...

Is the coral growers special on Cutter new or has that been reviewed here and discounted?

http://www.cutter.com.au/proddetail.php?prod=cut964

These are a special version of the Cutter XPGxxxx Led Engines.
Solderless Optic Holder for Carclo Optics

The 4 up is 1 x XPE Blue and 3 x XPE Royal Blue specifically on a 25mm Dia Metal Core PCB

The 7 up is 4 x XPG Cool White and 3 x XPE Royal Blue on a 40mm Dia Metal Core PCB

 

[widmer]

It's kind of a fun idea, but if I remember correctly, it is actually considerably more expensive than buying 4 individually mounted LEDs, especially after you factor the cost of optics. And of course for most purposes folks would prefer to have their blue LEDs more spread out and homogenized with the white LEDs...

I could picture a couple of 7-ups running off of a meanwell and positioned with medium-narrow optics like santoki has done, and that would be a lot of fun. But again, it would be considerably cheaper to simply mount 7 stars close to each other...

Although I actually just visited the link, and the 4-way linear royal blue is like $21 which is really a solid price @ $5.25 per royal blue xpe so hmmmm

 

[black_ice_pc]

Hey guys I've read through most of the thread, starting with Soundwave's original post. Great stuff and it helped me decide on the replacement for my old crappy PCs. I'm getting things together to build a LED setup. I'm basing it off of soundwave's original design, with some differences. So far I've bought
12 XP-G R5
12 XP-E RB
4 1000mA Buckpucks, dimmable
8.5" x 11" heatsink from heatsinkusa.
8.3A 24V PS from MPJA
other odds and ends
My tank is 47 x 17 x 27 ID. I just bought the stuff for one side of the tank for now due to money. A few questions:
Will 24 LEDs be enough per side? I'm open to adding more if necessary. Maybe I should add another set of 6 per side for a total of 60. Also how should I go about spacing the LEDs given the heatsink dimensions? I'm looking to keep LPS and moderate SPS. Montis and some acro. I"m fine with only having SPS in the top half of the tank. I'm planning on putting rics and zoas at the bottom

 

[widmer]

Will 24 LEDs be enough per side? I'm open to adding more if necessary. Maybe I should add another set of 6 per side for a total of 60. Also how should I go about spacing the LEDs given the heatsink dimensions? I'm looking to keep LPS and moderate SPS. Montis and some acro. I"m fine with only having SPS in the top half of the tank. I'm planning on putting rics and zoas at the bottom

That should be plenty. The mantra has been one LED per 10 - 20 square inches of tank footprint, but that was what we said for XR-E's. You've got XP-G's and XP-E's, which put out considerably more light, which I would roughly estimate to being equivalent to one XR-E per ~10 inches if you do a total of 48 LEDs. You may want to invest in some optics, potentially 60-degrees. This will allow you to run your LEDs more efficiently, because the optics will project the light more down into your aquarium than out of the sides of it.

 

[black_ice_pc]

Thank you widmer for the quick and helpful response! I'm aware of the wider viewing angle on the XP series LEDs, and was indeed planning on getting optics. I've had trouble finding any though. Do you know where I can find 60 or 80 degree optics for XP-E and XP-G?

 

[sammy113]

Thank you widmer for the quick and helpful response! I'm aware of the wider viewing angle on the XP series LEDs, and was indeed planning on getting optics. I've had trouble finding any though. Do you know where I can find 60 or 80 degree optics for XP-E and XP-G?

I believe there is only 40 Degree for XP-G/E

Don't know if something new came out

 

[der_wille_zur_macht]

Cutter has a ton of optics for all of these LEDs on their site; sadly most of them are pretty narrow and/or expensive. I don't know of any 60 or 80 degree optics for XP-G but I'm sure they're out there somewhere.