556tactical wrote:
Anybody know about epistar
or Cree LED lightbars I'm wanting to go with led bars but I don't have the kind of money to get rigid industries.$1000 is WAY too much
Epistar doesn't make packaged LED.
They make the boards they mount to for example.
So, if you look at the mounted LED, the board says Epistar...but, it could be any LED on it.
CREE is a known brand that is copied by cloning stations down to the smallest detail all across villages in China.
Some clones are impossible to tell the difference w/o a side by side performance comparison, or a magnifying glass, etc.
A real CREE XML2 for example driven at its full rated power might be close to $50 - $100 for each LED/driver/heat sink/optic.
In volume, that can come down, but if someone says they have a bar with say 10 of them for the price of one, you can quickly figure out that something had to give.
In testing, the $100 bars are garbage...the solder is spattered on, sort of, there's little to no gasketing or weather sealing, the optics are plastic junk with no UV protection, the wires are undersized and the LED are god only knows what really, but typically under driven well under their claimed out put.
For example, CREE might publish a data sheet that says at 3 amps, the LED puts out 1,500 lumens.
At one amp, it might put out 500 lumens, or 200, etc...depending on the heatsinking, or other losses, etc.
So, if the bar has 10 LED with a data sheet that gives a max output of 1,500 lumens, they advertise AT LEAST 15,000 lumens, and deliver closer to 2000 - 3000 etc....by the time you go through the less than optically transparent optic/lens, with an under driven LED on poor to absent heat sinking, etc...and even less when they fog up inside and start to corrode, etc.
So, there are reasons why two bars might look similar, and one is more. If its a name brand, there's a better chance it will at least be more durable, and, put out closer to the amount of light you imagined it might.
The other cheap bar issue is that the focus sucks...so you have a LOT of light right in front of you, which kills your night vision, so you can't see stuff off in the distance.
A good bar puts the light off int he distance where your headlights could not reach....and lets the head lights do the close up stuff.
Of course, the human brain will see the bright pool of light right in front, and think "Oooh, BRIGHT!" and even be convinced they bought a really bright light....because it LOOKS bright.
If you don't have light measurement equipment, its sometimes hard to tell how bright is bright...and, you might think 2,000 lumens, that they told you was 15,000 lumens, is bright...not knowing its a lot dimmer than it would have been if honestly labeled...
...and not realizing that you can't see stuff as far away as you would have, etc.
I DO have light measurement equipment of course, as I use it for work.
Places like Diode Dynamics (A sponsor here!) DO have lighting equipment, and do test their stuff, and DO tell you the actual output, not just the LED's theoretical output, etc.
Food for thought.
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