Originally Posted by
cyccommute
Overvolting reduces the amperage draw. Amps = watts/volt. A 10 W bulb at 12V draws 0.8 A while the same bulb at 14.4 V draws 0.7A and puts out twice as much light.
I'll agree that for weight LEDs are king. For lumens...not so much. Per unit halogen still put out more light...or can be forced to put out more. Halogens...the ***** of the lighting world
Ummmm, no. Light bulbs don't have a constant wattage regardless of voltage. If anything they have a constant resistance. Voltage = Amps * Ohms. So if you increase the voltage, you'll increase the current (and also increase the wattage, which is why they get brighter). If a 10W bulb at 12V draws .8A, then it's got a resistance of 15 ohms, and the same bulb at 14.4V would draw .96A. It would now be using 13.8W, so I doubt it would really be putting out twice as much light.
That assumes the resistance is the same, but it might change a little because the lamp would be running hotter. But it's probably fairly close.
Keith