DIY LED Array build

[sphil876p]

Coral color changes

Coral color changes

Many times I have purcased frags and the colors changed completely once the coral has acclimated to my lighting/water quality...
These corals were at the bottom of the Dealers frag tank approximately 24" deep under 20k lighting. I do not worry about the coral as long as it continues to encrust its base and exibit the same polyp extension as when I picked it up...
I have tried to keep several birds nest (stylophora) frags going and have not been successful to this point, they always seem to fade very slowly no matter where I place them.

 

[Reef_Matrix29]

Tonight I reduced my current from 700mA to 350mA to see if some of the pigment would return under less intense conditions. I will observe over the next few days and if I can, I will increase the current to 450mA over the course of 2 weeks.

 

[sphil876p]

Parts Sourcing update....

Parts Sourcing update....

I was just able to order three more of the Meanwell ELN-60-48D power supplies with out any problem from Powergate LLC.

The thermal transfer tape from Digikey turns out to be cheaper than I expected. Having read about it on the big LED thread I was expecting over 50$ per 10" x 10" sheet.....
That was LIST price :bounce2: when you order it online it is only 22$ plus tax and shipping....
Total was approx 30$ and enough transfer tape to easily apply 144 stars

linky... http://search.digikey.com/scripts/D...homepage_link=hp_go_button&KeyWords=BER159-ND

 

[sphil876p]

Got started on the next fixture this weekend.
I must say that the thermal transfer tape is awesome......
Assuming it does what it is supposed to do in moving the heat from the led to the heatsink, the tape makes layout and mounting a breeze. This new mounting technique saved me 4 to 6 hours and lots of headaches that I experienced with my first build.

 

[Reef_Matrix29]

Can you provide a pic of what it looks like so far?

 

[sphil876p]

Can you provide a pic of what it looks like so far?

I cut the transfer tape sheet to width in strips with a razor knife and straight edge...
Then used scissors to cut the individual pieces to fit the star. I just left them square, did not feel like making all of the little cuts....

 

[Reef_Matrix29]

Looks good Phil!

 

[reeformadness]

The squares should actually help keep your circuits from shorting and keep you from having to strip your wires to close. Nice work.

 

[Reef_Matrix29]

How strong is the thermal tape once it settles in place? Did you need to clean the heatsink and LED before applying the tape?

 

[magnoliarichj]

dose some AAs

 

[nitjt]

Phil did you think the tape will be stong enough to hold the stars and optics in place better than skrews?

 

[nitjt]

Anyone know when we will be albe to the the new Cree XP-G?

 

[nitjt]

I have seen this kind of tape around on one of these threads pre cut to fit the stars any know where I can get that?

 

[Hesham]

I have seen this kind of tape around on one of these threads pre cut to fit the stars any know where I can get that?

Pre-cut tape for LED stars is available at;

http://www.luxeonstar.com/precut-thermal-adhesive-tape-for-luxeon-staro-starc-9-p-461.php

They sell it for roughly a dollar a square. Suggest comparing the material from this site to the material someone else on the thread is buying from Digikey (a great source for electronic components). Datasheet for the material above is at;

http://www.bergquistcompany.com/pdfs/dataSheets/PDS_BP_100_12.08_E.pdf

The tape material is very strong - it can be used to hold heat sinks to CPUs. It is not as strong as thermal epoxy which can be considered a permanent mating.

Tapes are typically not as effective as thermal epoxy or grease as they do not fill the microscopic gaps between the two surfaces being mated as well as if you are to use the epoxy or grease. There are very high quality gap filling tape materials available including ones based on epoxy but these can be expensive and require specialized handling. Regardless, tapes are probably fine for our use in LED fixtures especially if we are moving air over the heat sinks.

The white paper below on the Arctic Silver web site gives a good overview of the surface imperfection issue;

http://www.arcticsilver.com/PDF/WhtPr/Thermal_Interface_Basics.pdf

Whatever you choose, make sure that the surfaces being bonded are cleaned or else the thermal performance and adhesion will be poorer.

These materials do have a limited shelf life; check with the manufacturer.

 

[james3370]

Anyone know when we will be albe to the the new Cree XP-G?

found these in a quick google search, but didn't read too much of it LOL

http://www.cpfmarketplace.com/mp/showthread.php?t=199888

http://www.cutter.com.au/products.php?cat=Cree+XPG

 

[der_wille_zur_macht]

Cutter has them in stock (as of a week ago) but their shipping policies to the US make me nervous.

 

[sphil876p]

How strong is the thermal tape once it settles in place? Did you need to clean the heatsink and LED before applying the tape?

Seems to be stuck pretty well...
I missed my layout marks, and had to peel a couple of them up to reposition which was fairly difficult for having just stuck them in place.
I went back after I finished mounting them and used a lens to get some leverage and really put some pressure on the stars....
I just cleaned the surface of the Heatsink with a little rubbing alcohol to make sure to clean any greasy residue that might have been on it.

 

[sphil876p]

Phil did you think the tape will be stong enough to hold the stars and optics in place better than skrews?

I believe it will hold fine, though not nearly the staying power of tapping holes for fastening... I used this to save myself the headache I experienced with my first build, and the hours of time I spent. All of this said, I mount my Heatsink with the attached LEDs in an acrylic enclosure for protection from salt spray. So, the LEDs with the lenses installed sit completely enclosed resting on the face of the lenses in my acrylic fixture....

 

[nitjt]

Should I two or three array over a 48" tank what's the widest heat sink?

 

[nitjt]

Thanks for all the help I don't want to get in over my head when building this