How to Power Your Arduino Connect a 9V battery to the Arduino Featured Written By: Madeleine Schappi )"> Difficulty Very Easy Steps 1 Time Required Resources Add Parts and Supplies to Cart Introduction Powering your Arduino is a crucial first step in almost any Arduino project. In this guide, we will show you how to power up your Arduino with a 9V battery. Doing so will enable you to begin with your very own creations! Tools Add Tools to Cart Uno R3 - Little Bird 9V to Barrel Jack Adapter Step 1 Connect a 9v Battery to your Arduino Connect a 9 Volt Battery to your Arduino using the supplied 9 Volt Battery Snap. Plug the connector into the external power port on the Arduino Depending on what you are asking the Arduino to do, the 9v battery can last 10+ hours!