Ebay Cree Cob Kit ???

  • Thread starter Shadrock5
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Shadrock5

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I came across this kit on ebay - yes it ships from china but it does say cb bin cree comes in 3500k - any one have experience cause it is a lot less then the ones on timber
Ebay cree cob kit
 
Homesteader

Homesteader

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Looks decent, most of those parts are coming from China anyhow including much of those pin fin sinks. You probably wont get the top end bins which may mean slightly less output) but the components look good as well as the lenses. You could build it for cheaper, but this is a good start I would think. Just get some aluminum angle bar and get cutting.
 
DGP

DGP

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The lenses are not needed and are counter productive, just a gimmick optically speaking because the radiation pattern of the COBs is fine without reflectors or lenses and are good to go on a 12" spacing (generally speaking may depend on your grow room requirements).

Most Cree LEDs I have seen marketed directly from China tend to be low bin ones they are getting rid of but it varies. They could be legit LEDs but maybe not. That is the problem with CHina sourced anything on Ebay, buyer beware....

Dee
 
S

Shadrock5

57
18
Looks decent, most of those parts are coming from China anyhow including much of those pin fin sinks. You probably wont get the top end bins which may mean slightly less output) but the components look good as well as the lenses. You could build it for cheaper, but this is a good start I would think. Just get some aluminum angle bar and get cutting.
I have tried to source the parts and pieces and I dont see how i could build for less especialy with the cree's i see them for like 31 bucks apeace cheapest.
 
Homesteader

Homesteader

3,473
263
I have tried to source the parts and pieces and I dont see how i could build for less especialy with the cree's i see them for like 31 bucks apeace cheapest.

You can always upgrade it with better COBs if they turn out shit. Cree COBs are built in China, the heatsinks are built in China, the Drivers are built in China (or Taiwan if you don't follow One China.) but I agree you never really know when they come from China on Ebay. I do however disagree about reflectors being not needed. 180 degree wastes a lot of energy when you could focus it downward at 120 or such. Its not a steal but it will get you going.


I think RapidLED is out of Vermont.
 
DGP

DGP

1,214
263
You can always upgrade it with better COBs if they turn out shit. Cree COBs are built in China, the heatsinks are built in China, the Drivers are built in China (or Taiwan if you don't follow One China.) but I agree you never really know when they come from China on Ebay. I do however disagree about reflectors being not needed. 180 degree wastes a lot of energy when you could focus it downward at 120 or such. Its not a steal but it will get you going.



I think RapidLED is out of Vermont.

LEDs do not radiate equally over 180 degrees. Also, the high angle light that does get out enters the canopy at an angle that can be helpful by entering under leaves that obstruct the direct lighting from above. So this light isn't wasted. Since LEDs radiate in a Lambertian pattern the higher angle light is a very small percentage of the total light produced. The majority of the light is coming out a a very usable angle. Also the plastic COB holders have a small reflector built into them that effectively redirects the highest angle light. The optional reflectors you can order bring the cone angle into 90 degrees which is a little too focused for me.

The length of the lines in the diagram below are showing relative intensity.

Dee

Lambert Cosine Law 1
 

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