I need some input on Cree XLamps

lotsaluck

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Specifically, will 3 of the blue or white have enough lumens, without any added optics, to throw 50' away enough to distinguish typical terrian? That is tell ground from water, trees from rocks? Not looking to be able to read a book from that range, just see to navigate. Currently useing the Lamina 7 cavity, and it is more than enough but gets waaay to hot.

Thanks...
 

vacuum3d

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It has no throw if you don't use any optics/reflector. It's not like those 5mm leds where you'd get some sort of focus without additional optics. The Cree has view angle of 100 degree. It is still very much a flood. You won't get a hot spot from it unless you gather the light with optics/reflector. If you want to know what it looks like, it is much like the Luxeons without optics/reflector.


ernest
 

lotsaluck

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Not wanting throw though so we were thinking it could be a good fit. We need the 100 degree spread, but want to know if three of them will still send enough light at 50' to see with. Not interested at all in burning a retna with it at that range. We have enough that can do that!
 

OddOne

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You have conflicting requirements where LED lighting is concerned - wanting distance without throw. Unless you use a REALLY powerful LED or sizable LED array (Lamina Ceramics BL-3000 or a dozen or more Cree XLamps or Luxeons), you won't generate enough intensity to travel that far, unless you use optics to perform some level of beamshaping.

oO
 

enLIGHTenment

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[ QUOTE ]
lotsaluck said:
We need the 100 degree spread, but want to know if three of them will still send enough light at 50' to see with.

[/ QUOTE ]

The generally suggested minimum light level for lightly used roads and paths is around 5 lux. This will be just enough to navigate. A completely isotropic source will need to emit just over 14,000 lumens in order to project 5 lux to a radius of 15 meters (~50'). This is well out of the realm of both LEDs and most incans.

Cutting down the full angle to 100 degrees horizontal and 45 degrees vertical will reduce the lumen requirement to around 500, which is doable with four or five Lux Vs at an power cost of 24 watts.

You can also get the same light output with a 10 watt MH HID setup or an underdriven 60 watt Edison incan.
 

VidPro

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50 feet, 100degrees, i would think about 30 3W luxes run to near spec.
course at 50 feet, thats gonna light up a whole back yard, minimally.
i dont know how that translates in CREE units :)

just a guess.
i am playing with a 10x3W bar now, that would give candlelight to a short back yard.
 

HarryN

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I will try to run a test in my back yard tonight - some of this depends on if you are willing to do any kind of optics at all, how picky you are - and your willingness to drive them at Lux III kind of power levels.

The X7090 at 1 watt drive is more or less the same light output as a Lux III at 1 watt - at least to my eyes. Which
is still pretty good.
 

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