Conversion of a 48" T5 to LED fixture

[Boga]

I have a 50 gallon tank that I use as refugium/frag tank/chaeto production. The algae occupy about 40% of the volume and it is my Nitrate "sponge". The other side of the tank has live rock and some egg crates for surplus corals.

My old 4x54W T5 is gone. The bulbs are almost gone. I will remove anything from inside and fill it with LED's, drivers, aluminum and lenses.

Thinking to have an aluminum plate 48"x4"x1/4" assembled in the housing, LED's mounted in two groups, left/right as shown in the picture, drivers somewhere inside, potentiometers for dimming, the existing fans will help with cooling.

So far I have just a sketch, but actively gathering ideas, thoughts, questions, feedback.

 

[Victoss]

Re: Conversion of a 48" T5 into a LED fixture

Looks good, I have no experience with LEDs used for algae growth though so you'll definitely want to make sure you research (which you probably already have) that before you make your order. I only say this because that's a lot of red, with it set up that way all the red might overpower the blues on the other side for your frags. You might just end up with a totally red sump.

 

[curiousphil]

Re: Conversion of a 48" T5 into a LED fixture

For the algae side you will want neutral white and reds.  Just replace the ones you have marked as RB with NW and you'll be good to go!

 

[Boga]

Re: Conversion of a 48" T5 into a LED fixture

...... I only say this because that's a lot of red, with it set up that way all the red might overpower the blues on the other side for your frags. You might just end up with a totally red sump.

Valid concern. Indeed, I won't like red light to flood the frag side, even if is just reflected light. Probably I am going to end up using 40 deg lenses. I will try to create a sketch to see how direct light will illuminate both sides. At this point I don't know how to answer (fix) this.

For the algae side you will want neutral white and reds.  Just replace the ones you have marked as RB with NW and you'll be good to go!

Honestly, this is what I thought when I started, and I was convinced that white and red will be the best. It looks that violet, blue and red LED's are matching the absorption spectrum for chaeto.
http://www.thefragtank.ca/forum/index.php?topic=7737.0

 

[curiousphil]

Re: Conversion of a 48" T5 into a LED fixture

Oh, interesting!

 

[Boga]

Re: Conversion of a 48" T5 into a LED fixture

In order to save some space, can I run 4 Royal, 7 Deep Red and 2 UV in series from the same driver? The driver Mean Well LPC-35-700 (constant current driver) is rated for 700 mA / 9-48 Volts.

All LED's are good for 700 mA, forward voltages as follows:
Royal Blue: 3.1 V
Deep Red:  2.4 V
UV:            3.5 V

 

[Victoss]

Re: Conversion of a 48" T5 into a LED fixture

You should be okay but my only worry is your going right up to their max current. If I was going to do this then I would definitely make sure I had enough fans to keep them cool. The better option would be to use a dimmable driver with a POT (if you don't have a controller). Then you can always dim them down if your macro algae is finding it too bright.

 

[Boga]

Re: Conversion of a 48" T5 into a LED fixture

You should be okay but my only worry is your going right up to their max current. If I was going to do this then I would definitely make sure I had enough fans to keep them cool. The better option would be to use a dimmable driver with a POT (if you don't have a controller). Then you can always dim them down if your macro algae is finding it too bright.

Thanks. Changed to dimmable driver.

 

[Boga]

Re: Conversion of a 48" T5 into a LED fixture

Update:
- Changed the LED layout on the chaeto side. I added 2 Violet UV LED's.
- I was looking for 40 degrees lenses for Philips Deep Red LED's. I did not find, so I have to go with 60 degrees on the red side. There is going to be light "contamination". I attached a theoretical light coverage over the tank (front view). Possibly chaeto will stop some of it ....? Maybe I have to add a partial black acrylic sheet between the two zones. ???

 

[curiousphil]

Re: Conversion of a 48" T5 into a LED fixture

I know that most of the light is contained within the first 20 degrees of the beam coming out of the lens, so that little bit of cross-contamination would be of very very minimal strength.  I doubt that a little bit of red would hurt the corals on the other side.  My fixture has 'ocean coral white' chips on it that contain a red, blue and green diode on every chip.

 

[Boga]

Re: Conversion of a 48" T5 into a LED fixture

I know that most of the light is contained within the first 20 degrees of the beam coming out of the lens, ........

Thank you very much for the info. Very useful.

 

[KBennett]

Re: Conversion of a 48" T5 into a LED fixture

Don't forget about refraction at the water's surface.  That will turn the light down at the surface.
I have no blues on in the right third in this picture.  My brace cuts it off a bit, but you can still see that there is no blue line at 120 degrees. I have no lenses.

 

[Boga]

Re: Conversion of a 48" T5 into a LED fixture

:-[ :-[ :-[ :-[ :-[ I forgot about it. Too long time ago in High School: Snell's Law

                                     

Easy online calculator can be found here.
http://easycalculation.com/physics/classical-physics/snells-law-calculator.php

For a 60 deg lens (in air), the incidence angle would be 30 deg, indices of refractions in air and water are about 1 and 1.333, respectively. This would give aprox 22 deg incidence angle in water and aprox 44 total angle of light in water.

Thank you.

 

[Boga]

Re: Conversion of a 48" T5 to a LED fixture

In the last few days I started to work on this conversion. Here are some pictures of the current setup before and some tear down pictures.

50 Gal REFUGIUM LIGHT BEFORE CONVERSION. Obviously, the left side is the frag side and chaeto on the right.



TEAR DOWN. Splash guard and brackets were removed.


TEAR DOWN. Detail of the T5's ends.


TEAR DOWN. T5 tubes were removed. Some of them were seized in the connector. I had to use screwdrivers to pry them out.


TEAR DOWN. Removed reflector and further disassembled the unit. About all the wiring in the picture was removed.

TEAR DOWN. Detail of one existing ballast (the white part). It was removed as well.

 

[Boga]

Long time since I did not update this thread .... I see that lots of pictures disappeared, probably in transition to the new forum, I will try to upload them via photobucket.

 

[Boga]

Long heat sink 46" x 4" x 1/4". All LED's were attached with screws. Drilled and tapped for 6-32, then used silver thermal compound between the LED stars and aluminum plate.


Below is a picture during assembly stage. Next one shows the Cheato's side LED's.

 

[Boga]

This was my drill template. Printed first on a piece of paper and then drilled at locations.







LED's on the refugium side:




Made some aluminum spacers between the aluminum plate and housing.









Hanged with chains:



And finally it is over my refugium and chaeto section.

 

[TORX]

Cool.

 

[scubasteve]

i want to do something similar for quite some time cool thread

 

[4Hummer]

Nice build.