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.
How to Build a Remote Kill Switch
Learn how to build a wireless controller to kill power when things go... sentient.
Qwiic Single Relay Hookup Guide
Get started switching those higher power loads around with the Qwiic Single Relay.
Single Cell LiPo Battery Care
This tutorial will go over how to safely charge, connect, disconnect, reinforcing the cables, and handle single cell LiPo batteries.
Breadboard Power Supply Kit 5V/3.3V Quickstart Guide
Quick start guide for the Breadboard Power Supply Kit 5V/3.3V