the_quadster:
Ok I will make this easy for me and not learn about buck converters and just get the 4 aa battery pack.
It's really not difficult to understand. I think learning about power supplies, voltage, and current will be worth your time if you continue to work with Arduinos.
Delta_G:
More than half.
But according to silly ol' Newton, energy is never lost. 
INTP:
But according to silly ol' Newton, energy is never lost.
What's that got to do with it? Volts are not and never have been a measure of energy.
Now if you had some amps and some volts and some hours you'd be getting closer.
Steve