Crummy headlights - Can't see, need upgrade
My old 2007 GMC has never had the best headlights. Driving from Lethbridge to Calgary last night I was really cussing them. Old original factory headlights and I cannot see worth a darn. They are...
Forum Discussion
pianotuna wrote:
Bob,
Power varies by the square of the voltage.
12.6 x 12.6 = 158.76
11 x 11 = 121
121 / 158.76 = 22% less light.
even worse than that.
on incandescent lights, light output increases about 3.5% for a 1% increase in voltage. for a car that means a 0.12V increase in voltage will increase light output by about 3.5%. typical drop between the battery and bulb with factory wiring can easily be 0.5V-1V. getting that 0.5V back will make a big difference in light output. A 1V increase in voltage will give close to a 30% increase in brightness.
Likewise a 1V drop from nominal will drop light output to about 70% of nominal voltage output.
Downside is that a 5% overvoltage decreases bulb life by 50%, while a 5% undervoltage almost doubles life. That's why the super long life incandesent bulbs are usually listed for 130V operating voltage, run at 120V they last a long time.
Most car bulbs are designed for about 13.5V
