Originally Posted by
kk4df
I rode for several years with a lithium battery and homemade LED lights for both commutes and brevets. I've recently put a SON dynohub with IQ Cyo R front light and a wired tail light, and I'll never go back to batteries. The light from the Cyo is less watts, but the more precise beam (not just a spot, but a well defined shape) gives plenty of light and the drag is imperceptible. And not having to worry about the need for extra batteries on the long brevets is great.
One other thing to keep in mind is that watts are a measure of power draw, not of light output. Two lights can have the same wattage but very different brightnesses, due to differences in efficiency. This is particularly true with LEDs, since the technology is advancing very quickly.