Is it an LED light?
I paid $150 for a 35 watt pair of bike lights powered by a heavy six volt battery in a water bottle that gave me six hours. These 3 watt LED’s are pretty much as bright and $6, run on 3 AAA batteries and weigh practically nothing.
I should have also mentioned that mine is old. It’s a Niterider 1200 pro. Now the newer models have 3,600 lumens and weigh a whopped 1.7 pounds total. 90 minutes of power at 3,600 lumens or 36 hours of power at 100 lumens with settings in between.
Check out this bad boy: http://www.shopbarska.com/Flashlights-1200_Lumen_High_Power_Tactical_Flashlight.html?gclid=CJG4xPzwt7ECFclgTAodV1IA7g