[aluka]

I'm trying to make a DIY led for my 2.5 gallon tanks, i was wondering if fans are necessary, since it will become really clunky. Would passive cooling be enough, if i don't encase the heat sink. This will be for around 3-5 watts of led. Will it be too warm?

 

[Wasserpest]

Really depends on the type of LED, how it is attached to the heat sink, size of the heat sink, and air movement around the unit.

Generally speaking, with a sufficiently sized heat sink and good connection between LED and heat sink you don't need active cooling.

 

[Hoppy]

A heatsink like these doesn't need a fan, but it can't be enclosed so air can't circulate around it. These are rated for about 10 watts of LEDs, but you can find them on Ebay for at least 25 watts of LED - they are just thicker.

 

[Deano85]

An old computer cpu heatsink would work well. You might be able to find one for free.

 

[aluka]

A heatsink like these doesn't need a fan, but it can't be enclosed so air can't circulate around it. These are rated for about 10 watts of LEDs, but you can find them on Ebay for at least 25 watts of LED - they are just thicker.

Where would you mount the LEDS? just in that center spot? If i get that i would probably mount about 5 1W LEDs. Do i mount them inbetween the grids?

 

[aluka]

An old computer cpu heatsink would work well. You might be able to find one for free.

hmm, i have seen someone do that for a 2 gallon pico reef, sadly i dont have one hadly. Maybe i can order online

 

[jeffkrol]

Where would you mount the LEDS? just in that center spot? If i get that i would probably mount about 5 1W LEDs. Do i mount them inbetween the grids?

Better photo showing 10W multichip LED

5/ $21

WOW 100W heat sink.......

$30.......... You can get a 50W (just thinner) for $18

 

[Hoppy]

Where would you mount the LEDS? just in that center spot? If i get that i would probably mount about 5 1W LEDs. Do i mount them inbetween the grids?

That's how I mounted a high wattage LED and two low wattage ones. You need to leave some of the fins exposed so air can flow up through the fins, but it works fine with this big a plate mounted on it. Why not just use a 10 or 25 watt LED on it?

 

[aluka]

oh it wont be too focused? cause a 2.5 gallon tank is rectangular. i wasn't sure if the sides would get enough light.

 

[Deano85]

I find the one watt leds don't get overly hot. They can be placed on aluminum channel or similar.

 

[Deano85]

This thread?
http://www.plantedtank.net/forums/showthread.php?t=294610