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.
PicoBuck Hookup Guide v12
The PicoBuck board is a high-efficiency three-channel constant-current LED driver.
Hookup Guide for the SparkFun RedBoard Artemis Nano
Get started with the powerful RedBoard Artemis Nano
Hookup Guide for the SparkFun RedBoard Artemis ATP
Get started with the RedBoard Artemis ATP - all the functionality of the SparkFun Artemis module wrapped in the Mega Arduino Footprint
Thing Plus Dual-Port Logging Shield Hookup Guide
This tutorial shows you how to hook up and use the SparkFun Thing Plus Dual-Port Logging Shield.