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.
Sunny Buddy Solar Charger V13 Hookup Guide
How to hookup the Sunny Buddy: a solar-powered, MPPT (peak-power tracking), LiPo battery charger.
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!
TPL5110 Nano Power Timer Hookup Guide
The TPL5110 Nano Power Timer is ideal for applications that require low power, and especially those projects that are running off of a LiPo battery. The Nano Power Timer will turn on your project after the set amount of time, continuously.
SparkFun RTK Express Hookup Guide
Learn how to use the enclosed RTK Express product to achieve millimeter level geospatial coordinates.