Bike Forums - View Single Post - Lumens exaggeration

11-13-12 | 10:46 PM

#14

cyccommute

Mad bike riding scientist

Joined: Nov 2004

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From: Denver, CO

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Quote:

Originally Posted by colleen c

Truth is the fact that the XML can only output 900 to1000 lumens if driven at maxium current of 3 amps. This fact is from the Cree Data Sheet.

A question about the XM-L T6 LEDs. Are they used as a single LED or as an array? Obviously, they aren't being operated at single LED at 3 amps. A more likely current draw is around 1.5 A or perhaps even around 1.0A. From the sheet, that puts the lumen output from around 550 lumens to 380 lumens. If you are operating an array of diodes, wouldn't that get the lumen output closer to the advertized level.

I've owned Magicshine 900, the 1000 and now Cree LED lamps that have noticeable differences in output. I've run them all side-by-side and there is definitely a difference in intensity.

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