DIY LED Array build

[g8gxp]

If you have optics on them, that should further filter them no? the covering on the optics aren't clear, at least not the ones i have, which are the same ones as sphil shows on the 1st few pages.

 

[kcress]

Interesting stuff. Keep in mind glass pretty much wipes out UV issues unless it's special UV transparent type. So, any light out of glass tanks should not be an issue.

The only lighting we've had in our living room for 16 years has been MH. LOL (But certainly not DE bulbs.)

 

[der_wille_zur_macht]

Interesting stuff. Keep in mind glass pretty much wipes out UV issues unless it's special UV transparent type.

How does that compare to acrylic?

Since many people are using acrylic splash shields, and/or acrylic optics, I'm wondering if the UV won't even make it into the tank, much less out in to the room.

 

[Canoe]

...glass pretty much wipes out UV issues unless it's special UV transparent type...

But, ...
unless you order coatings or special glass for your house windows, over time the UV coming in just from daylight, let alone sunlight, will fade fabrics and artwork and can breakdown plastics (like my speakers' cones). And I used to have to order special UV resistant glass for framing photographs (whether filtered by glass or coatings, I don't know).

but...
from: http://en.wikipedia.org/wiki/Ultraviolet
Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths while Silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.

but then later in the same article:
Ordinary, untreated eyeglasses give some protection. Most plastic lenses give more protection than glass lenses, because, as noted above, glass is transparent to UVA (ed. my underlining) and the common acrylic plastic used for lenses is less so. Some plastic lens materials, such as polycarbonate, inherently block most UV.

How does that compare to acrylic?

The example given to me was that the "1.5" acrylic eyeglass lens passes UV, whereas the "1.6" acrylic ones "fully block" both UVA and UVB (however, no transmission rate provided with either claim, i.e. %99.99 blocked). The "1.6" are "denser & harder" than the "1.5". No idea of units or if it's just a marketing designation. The statement some plastic lens materials, such as polycarbonate, inherently block most UV from the wikipedia article is interesting, but UV should not be a problem to begin with.

The point the doctor made is that with LED light sources, there should be no UV issue, with or without a splash shield, as any UV that may be generated by the device is in a low concern wavelength range, is low intensity to begin with and gets scattered and filtered before it leaves the tank - any UV left (assuming there was any to begin with) that makes it to the eyes is of a wavelength & intensity that is easily & regularly filtered by the eyes without damage. Direct viewing of any LED output is an issue to protect against. Having the LED device visible from its side in a lowly lit room may be an eye fatigue issue for some people.

That said, when I add a low-power UV string to pop colours, I'll make sure they're aimed into the tank and have a light shield to ensure they're not directly visible to the room - just because. And I'll make the string dimmable, to ensure I can tone it down if the total PAR is too strong, pushing beyond saturation and bleaching corals. Maybe low blue mixed with low UV is suitable for a moon light.

 

[Canoe]

... I'm wondering if the UV won't even make it into the tank...

We don't know if there is any UV at all from our visible spectrum LED devices.

Given how hard it is to get a LED to output a DWL in UV, and the published curves, any UV our visible spectrum LED devices are outputting has to be way under what we have in daylight.

Some CF bulbs are now reported to generate somewhat harmful UV. I guess to know for sure we need the manufacturer to state the values into the UV range, or have an independent test? Already done by someone?

 

[der_wille_zur_macht]

We don't know if there is any UV at all from our visible spectrum LED devices.

How can this be verified or tested?

I'm curious about this because I've just started construction on a plywood tank. There are several methods in use for protecting the inside surface of the plywood, but it's not really clear if any of them are totally superior in terms of protecting the epoxy/wood underneath from UV exposure (which will destroy plain epoxy.) Some people tint the epoxy with plain dye, other people use specific UV-blocking dye, still other people paint over the epoxy with Sweetwater brand epoxy paint, even though Sweetwater's marketing material states that the paint will degrade over time with UV exposure.

I'd rather be safe than sorry, but if an LED array won't produce a significant amount of UV, then I won't worry so much about UV protection inside the tank.

 

[Canoe]

I'd rather be safe than sorry, but if an LED array won't produce a significant amount of UV, then I won't worry so much about UV protection inside the tank.

To be safe, maybe a polycarbonate shield?

And easier to clean salt splash off of than the LEDs & optics...

What ticks me off is it's very reasonable to expect extremely low or no UV, but we don't know for sure.

 

[Hesham]

I am also curious about UV emissions of high power LEDs (expect it to be negligent) so I sent CREE the question. Also asked them if there is any infrared component to the light being output.

I'll post their response when they answer.

edit -> the support people at CREE appear to be on vacation/holiday until Monday (I'm getting multiple vacation notices)

 

[kcress]

People! Throttle back here!

UV is NOT an issue! Look at the spectral curves of our LEDs. There is nothing below 400nm. Even the royal blue LEDs have nothing.

If they did we'd be signing paper work to even receive them.

This discussion belongs under double ended MH or other types of eye dangerous MH lamps.

LEDs are quantum devices they are not thermal devices. They put out almost 100% of their light in the spectral zone they're designed for.

We don't need to be worrying about this subject with respect to LEDs. If you are dabbling with UV LEDs then you should be concerned - very concerned. You will also likely need to sign lots of legal papers to receive them.

This is just one more reward we get for using LEDs. No UV.

 

[Hesham]

Kcress - I (and I am an electrical engineer) agree completely about UV not being an issue for the LEDs used in this lighting application (and I have studied carefully the Cree light curves).

I decided to ask the manufacturer (ultimate authority here?) so that this question can be put to rest forever and ever ... or at least until someone asks again.

By the way, there are LEDs that are specifically designed to produce UV (http://www.roithner-laser.com/) but these are special use LEDs.

 

[Altpers0na]

hmm, now you have me thinking about led's for my bearded dragon.. darn you!!

 

[g8gxp]

man, there are so many led threads i'm not sure where to post a question but seeing as how we were discussing LED spacing earlier, I'll ask it here.

I've already drilled my heatsink for 2.5" spacing between leds. however, based on info in this thread this seems like it may be overkill, becuase i would ideally like to run them no less than 350ma just so it's not so dim. Is skipping every other one (5" spacing) too much? or should i just keep the 2.5" spacing and maybe raise the fixture to 8' off the water as opposed to 6"? I'll have optics as well because my tank depth is around 26" deep to the sand bed.

 

[sphil876p]

man, there are so many led threads i'm not sure where to post a question but seeing as how we were discussing LED spacing earlier, I'll ask it here.

I've already drilled my heatsink for 2.5" spacing between leds. however, based on info in this thread this seems like it may be overkill, becuase i would ideally like to run them no less than 350ma just so it's not so dim. Is skipping every other one (5" spacing) too much? or should i just keep the 2.5" spacing and maybe raise the fixture to 8' off the water as opposed to 6"? I'll have optics as well because my tank depth is around 26" deep to the sand bed.

In my experience so far, I believe that if you space the LEDs further than 2.5" apart with optics you will see the spotlighting effect we are trying to avoid. The poster who used fewer LEDs with greater spacing between each did not use optics.

 

[shackscs]

I finally ready to at least start the planning stage for my fishroom.

I have a huge project ahead of me and 16 4ft tanks is a whole lot of drivers, so far I am looking at two drivers per tank if I do 24 LEDs per 2ft section.

The dimmable Meanwells are on sale for $40.00ea but that is still a lot of drivers.

Are there any drivers that will drive more than 12-13 LEDs per string?

 

[Reef_Matrix29]

Where are these drivers on sale at for $40 shackscs?

 

[shackscs]

Rapidled.com They have been on sale for a few weeks now. I just ordered two of the non-dimmable ones to work with for now.

 

[shackscs]

Well after again looking over Menthol's tank and build, I am cutting back on the number of LEDs per tank and increasing the spacing. The tanks are only 10" tall so I will not need as many drivers but I would still like to find a driver that can run more tha12-13 leds per string.

Great tank Menthol.

 

[der_wille_zur_macht]

I would still like to find a driver that can run more tha12-13 leds per string.

Me too, but there don't seem to be any. The "biggest" chips designed for this task max out around 48v anyways, so I doubt such a driver exists.

Are you concerned about # of drivers from a cost perspective or a complexity perspective?

 

[der_wille_zur_macht]

PS - you've probably already considered this, but with 16 4' tanks you're going to be well into the wholesale bulk discount volume on these components, so it might make sense to shop carefully before you buy anything. I dunno if manufacturers would be willing to deal with an end customer, but at the least I'd hope you got a discount from a vendor.

 

[james3370]

PS - you've probably already considered this, but with 16 4' tanks you're going to be well into the wholesale bulk discount volume on these components, so it might make sense to shop carefully before you buy anything. I dunno if manufacturers would be willing to deal with an end customer, but at the least I'd hope you got a discount from a vendor.

ETG was giving the group buy on nano-reef.com a quantity discount......
http://www.nano-reef.com/forums/index.php?showtopic=194886