Originally Posted By Fooboy:
is the higher voltage a benefit and why?
Driving a 3+ watt LED to full brightness is a lot easier with 3 volts than with 1.5 volts - which is why most single-cell CR-123 LED flashlights are considerably brighter than their single-cell AA counterparts. Most LED flashlights convert the battery voltage to some higher value for the LED, but up-converting 1.5 volts is a lot less efficient than up-converting 3 volts - It draws roughly twice the current - and there's only so much current an AA cell can supply.
The trend even holds with 2-cell lights: Most 6 volt lights are brighter than their 3 volt counterparts.