The 7-LED lamphead Lupine Betty R 3600-lumen cycling light draws 40 watts from its LiIon battery pack, and is brighter than most Xenon car headlights.
And I don’t mean in theory. I’ve now had some more experience with the Betty R on wet rainy night rides, and I can say without reservation that it is by far (!) the very best light for night riding I have seen (and I do have some double headlamp fun occassionally).
Never before have I been satisfied with the light output while riding on a dark and wet night (black wet asphalt black-holes most of the light). The Better R changes that— a first. It is very, very impressive.
On dry lighter-color faded asphalt, full power is rarely needed, so battery power can be conserved. In such conditions, the Betty R is bright at maximum power anyway, especially if the white bike lane stripe is in decent condition.
The bike lights some riders use* cast a pitiful smear of pallid light a few feet ahead of the bike. The Betty R provides a broad and generously deep brightness that makes speeds downhill up to 35 mph perfectly comfortable (so long as my night glasses are not beaded with water droplets!).
* A multi-thousand dollar bike with an irreplaceable rider and a $50 AA-powered light = how much is your life worth, why not just skip the helmet too. Logic need not apply. From what I’ve observed, most riders are using lights that cost less than one good tire.