The Natural Philosopher wrote:
dcbwhaley wrote:
.
Fluorescents get about 100lm/W, the very best white LEDs, run under laboratory
conditions get around 30lm/W, and incandescents get under about 20lm/W.

So, about 50%, 15%, and 10%.

Why do torches and headlamps with LEDs have such an improved battery
life when compared with those with incandescent bulbs? It is
certainly more than the 50% that your figures would suggest.

I have always heard 1-2% for incandescents.

This does not make it actually correct.

Not nearly 10%.

http://en.wikipedia.org/wiki/Incandescent_light_bulb
as the first source I find gives 9% for halogen.


Cycle lamps that *pulse* make use of the fact that we can detect short
high energy light a lot better than long dim light..

Only if the flicker is actually perceptible.
If they don't flicker, then they are just as bright - or perhaps less so
for LED physics reasons