China stars
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blasterman
Flashlight Enthusiast
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Most of the Chinese 'cheap' LEDs are either Epistar or Bridgelux, or a knock-off of either. I've used a lot for various projects, and there are some thngs to watch out for. First, color tends to suck with Chinese 3-watts. Unless you are just trying to throw lumens at something don't trust kelvin ratings or CRI ratings. Next, don't even try to run a 3watt Chinese LED over 700mA. Last, the mounting of the emitter to the star tends to always be flaky with the real cheap stars. While I've encountered my share of 'basement reflow' jobs that fall apart by and large the higher end emitters tend to have higher quality mounting.
In short, if you can get them real cheap, they're worth 'beater projects'. At 700mA they'll run fine and I have hundreds running over 20k hours.
In short, if you can get them real cheap, they're worth 'beater projects'. At 700mA they'll run fine and I have hundreds running over 20k hours.
blasterman
Flashlight Enthusiast
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yep
More expensive ones tend to be more efficient, not more durable. Although I have no idea why anybody would pay $2.50 for an Epistar when a Rebel ES costs $3.00
More expensive ones tend to be more efficient, not more durable. Although I have no idea why anybody would pay $2.50 for an Epistar when a Rebel ES costs $3.00
Changchung
Flashlight Enthusiast
Exactly... I preffer the same. Pay just a little more and buy the good one...
SFMI4UT
dandism
Enlightened
Is China the brand that makes these stars you're talking about?
Update on usage:
China is the country, not the brand; They are from:
http://hanhualed.en.alibaba.com/product/611898092-209875758/3w_660nm_led_of_superior_lumens.html
Now after having used hundreds of them for several months, I'd say they are a very good deal. No customer returns, and only one "bad" LED that was visibly dim during testing.
One puzzling thing: We use a constant current 700ma supply (also from china) which handles 1 or 2 stars. The stars are all binned at "30-40 lm", and sure enough, whether 1 or 2 stars per supply, they are all visibly identical. However, the heat output of the supply and the LED heatsink varies drastically from one to the next. One can be lukewarm, while the next one almost too hot to hold. However the brightness is visibly identical (we don't use meters).
I'm guessing that the variable-ness in the LEDs is causing the supplies to adjust power greatly in order to reach the 700ma, but once the 700ma is achieved, the lumens are in the proper range. Does this sound right, or is it possible that the lumens are actually drastically different and we just can see it without meters?
China is the country, not the brand; They are from:
http://hanhualed.en.alibaba.com/product/611898092-209875758/3w_660nm_led_of_superior_lumens.html
Now after having used hundreds of them for several months, I'd say they are a very good deal. No customer returns, and only one "bad" LED that was visibly dim during testing.
One puzzling thing: We use a constant current 700ma supply (also from china) which handles 1 or 2 stars. The stars are all binned at "30-40 lm", and sure enough, whether 1 or 2 stars per supply, they are all visibly identical. However, the heat output of the supply and the LED heatsink varies drastically from one to the next. One can be lukewarm, while the next one almost too hot to hold. However the brightness is visibly identical (we don't use meters).
I'm guessing that the variable-ness in the LEDs is causing the supplies to adjust power greatly in order to reach the 700ma, but once the 700ma is achieved, the lumens are in the proper range. Does this sound right, or is it possible that the lumens are actually drastically different and we just can see it without meters?
