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.

Not nearly 10%.

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