Reducing Arduino Power Consumption
Contributors:
Alex the Giant
Alex the Giant 
Resources and Going Further
More information on low-power modes and options can be found in the datasheet for the 328P.
For more power-related fun, check out the following SparkFun tutorials.
Measuring Internal Resistance of Batteries
Classroom STEM activity that has students build a battery from a lemon, measure the open and closed circuit voltages, and determine the battery's internal resistance.
Battery Babysitter Hookup Guide
An introduction and getting started guide for the Battery Babysitter - a flexible LiPo battery charger and monitor.
Beginner Parts Kit Identification Guide
The essential parts for beginning (or even experienced) hobbyists that gives you all of the basic through-hole components you will need to get started playing with embedded projects. We'll identify a few parts in the kit and provide a few basic circuits to get started!
smôl Power Board AAA Hookup Guide
Small in size, small on current draw. It's a smôl world! This guide will get you up and running with the smôl Power Board AAA.