Originally Posted by
pierce
the XM-L is a single LED that has like an array of LEDs on the chip. The data sheet says it IS rated for 3000mA (which is 3 amps) at 3.3 volts, aka 10 watts (3.3V * 3A == 10 watts). The XM-L lights I've seen have 1 2 or 3 of these, for < 1000 lumens, <2000 lumens, or <3000 lumens.
the cheap noname chinese ebay lamp I have gets very very hot on its 'high' setting, which is IMHO insanely bright, but its low setting is about 1.5 stops dimmer (1/3rd as bright) and the lamp just gets barely warm. I have the action led spreader lens on it, and even on low its way plenty of light for road riding. the bright setting would be totally blinding to oncoming cars, even if its aimed down at the ground. I compared it with the H4 80/100 watt in my motorcycle (stock H4 is 55/60 watt) and this chinese cree lamp is brighter, even when spread . I just wish it had a clean cutoff.
I think it would be cool to try and put one of these LEDs in a Hella MicroDE projector fog lamp and see how that works. the MicroDE is meant for a 55W H3 halogen bulb (there is also a HID driving light version, which is a spot pattern rather than a fog spread)
Originally Posted by
colleen c
I think member pierce is correct. The XML is a single LED on a die with an array that are link together. You can see about 6 of these arrays where each one is a rectangular shape. Unlike the older MS900 P7 where the P7 have 4 LED place on the die, the XML looks like maybe 6 arrays of LED. Not sure if what I stated is correct but someone who is more knowlege may provide a better answer. I posted a picture of the LED while it is lit up. You can see the six row that are separated from each other.
The MS900 P7 is only about 500 lumens out the front and has a much greater spill. The XML in most lights gives out about 700 to 850 out the front lumens. The hot spot and corona is much more intense making the lights much more useable and brighter.
I think you both misinterpreted my question. Looking at colleen c's picture, is each LED in the array a discreet LED with a discreet output or is the output measured for the whole chip? It is unclear to me, reading page 2 of the Cree data sheet that colleen c linked to, whether the output is measured for each LED in the array or for the whole device. At 700mA, they say that the lumen output for an XM-L T6 is 280 lumens. If the whole chip is the "LED", then would the total output at 700 mA be 280 lumens or if each LED is putting out 280 lumens at 700 mA, the total light output would be close to the 1800 lumens listed by some manufacturers.
Like I said above, I've run the 900 and 1000 lumen Magicshines next to the Crees I have. The Cree has a narrower beam but they are far brighter than the Magicshines. They seem too bright for the reflector to be the
only reason for the output.