Just to give you some idea of the heat these guys can generate, I'm using a 1.813"(Fins) X .95" X 32" aluminum heatsink. Its a pretty large piece of metal, I have 10 CREE XP-Gs on them and with the dimmers set at 50% they stay room temp, 65%+ and they get really hot fast. I'm talking cooking eggs hot, hospital grade burns. The drivers are 1.3A with the LEDs supporting a max of 1.5A.
I've pretty much stopped using any LEDs over .750mA, just too much heat to the heatsink for my applications.
I've avoided the screw-in/thermal route by using thermal pads, double sided thermal tape basically and just love them.
I've never tried using an LED without a lense so I can't help there. One odd note, the Phillips lenses were so much easier to mount than the CREE lenses. About 1 in 5 of the CREE lenses have excess plastic inside that makes mounting them a pain.
I started out just playing with them but the results were so nice and the energy usage was so much less than the T5/CFLs I have that I'm replacing all my lighting with LEDs as they burn out. I have some rambling with the math around here somewhere. It is an upfront cost to save over the years, assuming your LEDs make it to the break even point. According to the specs they should easily do that and still have over 50% of there life left.
I have to agree with AV the LEDs I bought last year already have a new model out.
Sorry for the super late response!
Av8tor1, thats what Im afraid of, I don't want to overdo it and fry my plants .. I searched for variable current drivers and I can't seem to find anything for sale (google just gives me constant current drivers)
Im going to shorten the false bottom in the tank by an inch or two, but Im still figuring out how Im going to raise the fixture higher above the tank.. I think Im going to grow low canopy plants mostly (Utricularia, drosera, and Cephalotus); I'd love to try growing heliamphora again, but the conditions in the terrarium are too lowland for them (as well as epiphytic Utricularia ) I think (temps have stayed between 74 and 78 so far with no drastic drop at night; I don't have a fan set up in the terrarium yet, but I don't think it will really affect the temperature)
I would be more apprehensive if I were going to build a lamp for anything other than a single 10 gallon terrarium, plus I think it will be a good learning experience.
RSS, wow, thats pretty crazy, how did your LEDs fare after getting that hot? I still need to figure out how much the heat sink I plan on using can handle (hopefully it will work okay since it utilizes a fan for active cooling; it also comes with enough hardware to mount 37 LED stars, although I have no intention of using that many.)
Ive run across the thermal pads before and they look really cool, but I want to make my set up as reusable/adjustable as possible (which is why I want to use a heat with a screw and bolt mounting system)
Thanks for the tip with the lenses, I'll make sure to get the philips lenses if I need them!
.. Once I figure out if the Heat sink I want is usable, I'll order it, a driver, a power supply, and a couple LEDs to test out over my tank (I'll have to select a test subject, sorry to the plant in advance..) hopefully everything works out okay!
Last edited by Pk93; 07-13-2014 at 10:24 PM.
I've never let them run that hot for more than about 30m total, it was during the initial testing/construction process that I found this out and adjusted my plans accordingly. From my experiences I would never run the 1.5A LEDs over .750 or so, I'd just add more LEDs around that current level, but as I've said in a lot of posts I'm in this for the long run and paying upfront for massive savings later is why I'm buying them.
I do plan to pick up one of the Current Satellite LED+ premade fixtures to replace an older T5 aquarium fixture that finally burned out so I'll try and get a write-up on that after 6-12m. 600 Lumens, 36 par @ 12", 28 par @ 18", from an 18" 13W fixture. I still need to look up the stats for an 18" T5 to see how much gain/loss I'll be getting.
I have no fans intended to cool the heatsinks, there are a few fans by the heatsinks but they are intended for the plants not the lighting.
The Phillips lenses will not fit the CREE LEDs I have, last years model, if you went with CREE ones you have to get CREE mountable lenses.
Make sure to read through http://www.terraforums.com/forums/sh...ctral-research so much info in the 2nd link.