chinese led lights
- Thread starter stevercleeze
- Start date
- Status
BigCountry74
New member
TropT is all over it.....good stuff man.
TropTrea
New member
If you look at Crees data on LED's you wil;l see that various LED's do have shifts to various extents by thermo warming. But even more important is how heat shortens the life span of a LED. Many of the Cree LED's can be run well above there rated currents however there lifespans are drasticly reduced becaus regardless of the size of the heat sink it could not pull away the heat fast enough.
A while back I saw a chart from another LED manufacturer that gave heat sink requirements for there 3 watt LED's They recommended for running at a full 3 watts each LED should have 25 square inches of surface cooling. With a LED running at 2 Watts 16 square inches were recommended and with 1 watt they recommended 12 square inces of cooling. This is without fans and with the addition of fans you can decrease the surface area by up to 70% dependent upon the flow from the fan. It is only when you get into the small mili-watt LED's that cooling is not needed.
Now if you look at some heat sinks they have the appearance on an E only with multiple fins. ?These fins are designned to increase the surface are to provide cooling. A typicial 1" thick and 2" wide heat sink will have fins that are 1/8 thick and 7/8 tall and 1/8" apart. So over the 2 inches of width you have 8 fins and a total of 16 square inches of surface area per inch of lenght. So on a heat sink of this design you could technicaly put a 3 watt LED every 1 5/8" apart without having to worry about fans.
But the important thing to remember is the biggest cause of electronic devices to fail is heat. LED's are electronic devices. So the more cooling they get the longer they will last. And yes LED's do get hot especialy the higher wattage ones but newer designes are getting better and better every day giving a better light to heat ration from the power they are using.
ganjero
saiperchémibatteilcorazon
Great info on LEDs, Thanks. Do you know if these "Black Boxes" do not have a heat sink? If they don't, I see all that you explained applies to these fixtures and will be a major disadvantage. Also, what surface are they using to put the LEDs together?
submersible
Member
The ebay "taotronics" fixtures do not have traditional heatsinks, they use "kinetic theory of air" lol. The leds are mounted on an aluminum sheet, with THREE fans blowing directly on the opposite side, and air exiting out of the sides of the fixture. I would think this should be adequate to dissipate the heat? One of those infrared temperature guns would be nice to see how hot the leds are running.
The eshines fixtures do have heatsinks.
TropTrea
New member
This could work and I have considered building on an Alumnium plate. It all depends mainly on how much wattage they are running the LED's at, how close the LED's are to each other, And how effective the fans are. If there realing pushing the edge of max effectiveness of the fans then I would say.
1 Watt LEDs 2 1/4" apart
2 watts 2 3/8" apart
3 watt 3" apart
I know from tests we did on cooling transistors it only took a little more of heat sink to realy extend some cycle time capabilities but then when you a point doubling and trippling the heat sinks only delivered a small % of additional cooling.
When I did my planning using a flat sheet I looked at a 120 gallon tank with
1,152 squar inches of surface area for the plate size. Using 3 Watt LED's I would be limited to about 90. But did I realy want a Plate covering the whole tank and I was questioning if that would even give me enough light. From what I know now though it would more than enough light.
tntneon
SPSahollic
-Do say whites thend to shift to more red or bleu , when they heat up ?
greetingzz tntneon
RDHDDRAGON
New member
Mine are definitely not photoshopped.
I welcome anyone who wants to come by and see them. I am fixing to post my newest pic to that link. I have recently ordered some uv strips to see if it will help bring back the red i lost. It was only in acans and zoas though, the red turned orange. In my chalices the red stayed red and is as beautiful as always.Corals that were originally orange are gorgeous glow in the dark orange now.
All types of shrooms hate them. Zoas love them and are just multiplying like crazy.
As far as heatsinks and heat go, the leds are mounted to aluminum on mine. The air coming out the fans is cool. I can put my hand on the bottom of the fixture and it is warm, but not hot. You can hold your hand on it no problem at all.
TropTrea
New member
-Do say whites thend to shift to more red or bleu , when they heat up ?
greetingzz tntneon
On a red LED from 25 C at 100% flux, at 150 C the flux drops as low as 50% while a blue only drops to about 85%. If the white act the same way then you will have a considerable shift to blue.
They do not show the color shift for whites but do give a chart of the loss of light intensity as the heat up. On the colores (blue and royal blue) they list a possible frequency shift but do not say which way it goes.
Therefore I'd me more worried about loss of brightness as the LEDs heated up and if they got too hot an actual shorteng of there lif span more than anything else.
TropTrea
New member
I'm using Allumnium chanelling with my LED's mounted to it. The Channeling probably heats up 10 to 15 degrees C after the LED's are on for 8 hours. But even after a half hour the LED's temselves are extremly hot. If you touch tem you can barely keep your hand on them without thinking you get burned but they are not quite hot enough to burn you.
I actually just read this whole thread and while I was VERY close to pulling the trigger about halfway through, now I'm just tired...:hmm5:
My big concern is the size of my tank. 300 gallons, 96"X24"X31"H. Being 31" deep I want good light penetration. I always pictured LED's on my ceiling with very tight optics. I thought that looked awesome in some DIY threads where they had lights four or five feet above the tank but virtually no spillage. Currently only a FOWLR so the par is not critical. Really it's an aesthetic thing but I want the option to add corals later if I want to.
Like everyone else I've been waiting. I have a 4ft T5 fixture over my 8ft tank atm and it's killing me! Last thing to upgrade from my 100-300 move.
Any suggestions? What would you put over your 8ft 300g tank? Could I get away with only 3 of those black boxes?
My big concern is the size of my tank. 300 gallons, 96"X24"X31"H. Being 31" deep I want good light penetration. I always pictured LED's on my ceiling with very tight optics. I thought that looked awesome in some DIY threads where they had lights four or five feet above the tank but virtually no spillage. Currently only a FOWLR so the par is not critical. Really it's an aesthetic thing but I want the option to add corals later if I want to.
Like everyone else I've been waiting. I have a 4ft T5 fixture over my 8ft tank atm and it's killing me! Last thing to upgrade from my 100-300 move.
Any suggestions? What would you put over your 8ft 300g tank? Could I get away with only 3 of those black boxes?
tntneon
SPSahollic
-I always thoughed that the light of my fixture is about 12 °K when the cycle of 100 % bl/ 100% white started and when heated up it's more like 15°K ( a little bit bleuer) , it can be that it's only in the mind or that my eyes have to adjust to the bright light.
But it never been more red (the light spectrum when heated up that's for sure.
-I'm gonna use a 3 X 48 W leds box + 60 w led box + 4 X 39 W of t5 to lit my 154 G.
It's gonna be an SPS system , so i think it would be fine for soft's but for sps corals i would personaly have at least one more box IMO .
greetingzz tntneon
TropTrea
New member
the narrowest beam lens I know of are 40 degree which would normaly work on a 31" tall tank. But depending on how high your ceiling is above the tank you would probbaly get some spill of light around the tank.
for LED lighting on your tank I would look at something close to 300 watts minimum. If you wanted to go eventualy into SPS corals consider going 400 watts of LED's minimum.
lil_man72
New member
you would need atleast 4, one covers about a 24" square. you could keep most corals but the sps corals would have to be placed higher up under the fixtures.
BigCountry74
New member
X2 you need 4 boxes over a 8' tank.
I run 3 over my 6' tank and that's perfect.
4 and you should be good to go. The 3w boxes are definitely bright enough. I picked up some frags to start testing the lights on Friday and they are all doing well. I had to move them all to the bottom (tank is 24" deep).
The biggest adjustment to LEDs for me is the mental thing. You keeping telling yourself "these lights are not bright enough" because there is no heat generated, but they are definitely as bright, if not brighter than MH...
I run 3 over my 6' tank and that's perfect.
4 and you should be good to go. The 3w boxes are definitely bright enough. I picked up some frags to start testing the lights on Friday and they are all doing well. I had to move them all to the bottom (tank is 24" deep).
The biggest adjustment to LEDs for me is the mental thing. You keeping telling yourself "these lights are not bright enough" because there is no heat generated, but they are definitely as bright, if not brighter than MH...
TropTrea
New member
what people forget is that is a lot more to lighting than simply how bright a tank is. If we were just concerned about brightness then we would all be using just XM-L cool White LED's since they give off the most Lum's per watt of power. But everyone that has worked with corals for any lenght of time will quickly realize that those LED's do not put out nearly enough short wavelenght light to keep our corals happy.
Getting the proper balance between blue green, and red light is very important. Your balancing between the needs of the coral, which changes between different corals, and your personal eye taste which changes from one person to another. Most off the rack lights are mearly a compomise based on what the manufacturer thinks will work best for the biggest part of there market.
Sure with a dimmable you can custom yur lighting. But keep in mind when your running your LED's at 50% power your not running them the most effeciently. Why buy 60 LED's running and run them at 50% when you could get the same light from 30 runnining at 100% power.
- Status
