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.
ESP8266 Powered Propane Poofer
Learn how Nick Poole built a WiFi controlled fire-cannon using the ESP8266 Thing Dev Board!
Adjustable LiPo Charger Hookup Guide
The SparkFun Adjustable LiPo Charger is a single-cell lithium polymer (LiPo) and lithium ion battery charger. Because it’s adjustable, this charger will be able to safely charge all of our singe-cell batteries.
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
ATX Power Connector (4-Pin) Breakout Hookup Guide
Do you need to power a project with 12V and 5V from one wall adapter? The ATX power connector breaks out the standard 4-pin computer peripheral port for your 12V and 5V devices!