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.
LiPo USB Charger Hookup Guide
How to charge your LiPo batteries with the USB LiPo charger. Plus how to modify your charger to set the charge current.
ESP8266 Powered Propane Poofer
Learn how Nick Poole built a WiFi controlled fire-cannon using the ESP8266 Thing Dev Board!
Beefcake Relay Control Hookup Guide
This is a guide for assembling and basic use of the Beefcake Relay Control board
Battery Babysitter Hookup Guide
An introduction and getting started guide for the Battery Babysitter - a flexible LiPo battery charger and monitor.