This report describes the projects we’ve done over the period of project implementation. Battery tester is about software and hardware to use Arduino to check the supply of energy contained in the battery. It also allow users to control the supply of batteries can still be used. In this report describes in detail the problem statement on the project we performed throught out the project. The problem that often occurs among users is the battery usage battery life without knowing it until it runs for unpredictability. This project will be implementing using Arduino by using C programming language. Hopefully any information which will be explained in many ways readers can also benefit us. In addition, it can provide guidance and strength in the face of all the problems we confronted when I will make a real project.