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.
Battery Technologies
The basics behind the batteries used in portable electronic devices: LiPo, NiMH, coin cells, and alkaline.
INA169 Breakout Board Hookup Guide
How to interface with the INA169 Breakout Board to measure current.
LTC4150 Coulomb Counter Hookup Guide
A "Coulomb Counter" is like a gas gauge for your battery. Here's how to use it.
What is a Battery?
An overview of the inner workings of a battery and how it was invented.