What thermal paste for replacing LEDs

[oreo57]

Tim, no offense taken. Although I do know what stars look like, I'd be the first to admit that I'm an idiot when it comes to electronics. I know enough to be dangerous...... And I'm idiot enough to try anything, even though I know not what I'm doing.

I agree that I'm not crazy about the thermal interface, but this company was around for maybe five years or so before the owner had some pretty bad medical issues. We have a couple folks in our local club who have the same brand, but not as old as mine....and don't have this issue. Right after I purchased mine the company started producing adjustable ones (first with pots) and then eventually interfacing with controllers (aka Apex).

It obviously was a heat problem that cooked this unit and I'd really like to know want caused it. I'm not 100 percent convinced that having one of three fans out was the cause. (My other Apollo unit...all three fans running....also has some LED's fried....but not as many.) Although it could be a design flaw, I'm wondering if the lack of complete thermal compound on the aluminum fins could have caused the problems. By the way my fish room never gets hotter than 76 F or so....air conditioned in the summer.

Although I can do this fix for only 40-50 bucks, I'm still up in the air whether I want to take that route or purchase something else. Decisions!

circuit board w/ zero ohm resistors, some diodes, and obvious design problems (your not the only one w/ blown LED's.), no name drivers w/ ? specs..

Yea rebuilding is getting a bit shaky

 

[oreo57]

Replace all the white crap they put on the back of the LED's with decent thermal paste like Artic Silver, also change the Thermal Tape on the heatsink bars to thinner, better stuff, (even cellotape works better then that gold crap they put on it, its too thick to transfer heat away properly), that helps them cool better, they wont blow as much

I built three of these from scratch 2 years ago and they are still running strong on grows, check this out. 2 Modified Apollo's with 1 Bysen Bsled sp 112D

.


http://www.rollitup.org/t/kind-led-grow-apollo-led-rebranded.823971/

 

[redfishblewfish]

Tim, I've kicked around building my own fixture(s) for years, and every time I've added up the costs, it greatly exceeds the cost of commercial units......and would look homemade. I don't mean to sound vain, but I like the look of commercially finished fixtures.

Oreo, you're killing me....first don't do it and then do it! Although this second bit of info you've supplied is promising and might tell what the actual cause was.....poor quality thermal compound. So now I'm leaning towards doing the fix. I'm going to sleep on it and mull a bit more. However, I'd appreciate comment on what is meant by, "change the Thermal Tape on the heatsink bars to thinner, better stuff.." What is thermal tape and do I have heatsink bars? And if so, what would be a good "thinner" stuff.

Thanks again for this information....I'm learning quite a bit of stuff.

 

[oreo57]

Oreo, you're killing me....first don't do it and then do it! Although this second bit of info you've supplied is promising and might tell what the actual cause was.....poor quality thermal compound. So now I'm leaning towards doing the fix. I'm going to sleep on it and mull a bit more. However, I'd appreciate comment on what is meant by, "change the Thermal Tape on the heatsink bars to thinner, better stuff.."

That may just refer to a manf. difference. Your heatsink just had a bit of thermal "goo" Theirs may have used the same type "goo" but in tape form.. Comes in all sorts of forms;
http://solutions.3m.com/wps/portal/...cs/Products/Product_Catalog/~?N=7234361&rt=c3
Aqs to flip flopping.. what can I say...

Those "brick" types have never been my favorite to begin with..Lots of power, lots of heat.. all squished together..

 

[redfishblewfish]

But the conundrum with the Apollo is that there are so many other 55 LED 120W, 3 W bulb fixtures out their with similar design (did I say similar....I meant exact!) that are still working just fine with no LED burnout. In fact, the "temporary" fixture I have up over my tank is a very old TaoTronics fixture I originally ran....surprise, surprise...55 LEDs, two circuits, blue and white. And this old TaoTronics, the fans only come on when the whites are on. This fixture looks as good as the day it was bought.

EDIT TO ADD:

Now I know you can't judge lights by what our eyes see, but here's my tank with a TaoTronics on the left and an Apollo on the right....and if I did close-ups, you'd see the polyps extended on the left.

 

[perkint]

Tim, I've kicked around building my own fixture(s) for years, and every time I've added up the costs, it greatly exceeds the cost of commercial units......and would look homemade. I don't mean to sound vain, but I like the look of commercially finished fixtures

It's not vain to want a polished looking product! But you can do it with DIY without increasing the cost too much. As for the DIY price ending up more than an off the shelf solution, it is very easy to do that, yeah. But only because you end up building a better spec'd light than the budget ones you compare with!

As for a DIY that looks good, have you seen the new Rapid LED enclosure? Some pics in this thread:
http://www.reefcentral.com/forums/showthread.php?t=2489817

Or promazines excellent DIY (from another forum):

I still think that is one of the best DIY finishes i have seen!

Tim

 

[redfishblewfish]

Very nice looking DIY.......However I've made the decision and ordered the replacement LEDs and Noctua NT-H1 Thermal Compound for the LED connections and Arctic Silver 5 for aluminum finned to flat aluminum plate connection.

 

[perkint]

To be fair, for the price a repair seems worth a punt

Tim