Originally Posted by
mrbubbles
The electronic I'm using puts out 7 watt, not 3.
http://pilom.com/BicycleElectronics/DynamoCircuits.htm
That puts the wattage per led at 1.75 each, based on the spec sheets from cree, that's an average of 180 lumens per watt, theoretically 720 lumen, but accounting the real world loss from optics and whatnot, 600 lumens.
I have another 6 cree xpg gen 2 lights to post soon, and it's definitely not 3 watts and definitely more than 1000 lumens.
Inspired by this from ktronik at mtbr.com
http://forums.mtbr.com/lights-diy-do...iy-413443.html
That's 5 years ago using Cree XR-Es.
Mine will be a lot less clunkier.
Dynamo can definitely put out more than 600 lumens, commercial lights like Supernova E3 triple puts out 800 lumen.
Apparently neither your nor the source you cited understand electronics nor basic physics. The dynamo (which provides ALL of the power) can only output 3W. You can increase voltage at the expense of current, or current at the expense of voltage; however, the total power remains the same (ignoring conversion losses).
You are powering your LEDS with 3W of power-period.
You are not likely (as in certainly not) getting the LUMENS you claim. Even the Supernova only claims a
MAX brightness of 800 lumen. It doesn't actually provide the measurement when it is powered from a standard 3W hub...
Further, your setup exhibits all of the problems common with battery powered lights without the advantage of being able to draw more power than a dyno can provide. Specifically, your optics waste much of the light generated on the sky and other areas you don't need light. You would be far better off with even the cheapest dyno lights that at least have properly designed optics to make use of the limited power available in a dyno set-up.
Also, rather than misunderstanding physics and arguing about it, just pick up a cheap light meter and show us the measurements.