How to Build a Simple Arduino Battery Monitor for $5


Building a battery monitor with Arduino is an easy and inexpensive way to keep tabs on your battery's voltage level. With just a few components, you can assemble a simple circuit on a breadboard that will accurately read and display the voltage of a battery. This project is beginner-friendly and can be built in under an hour for around $5!

In this guide, I will walk you through the process of building a basic Arduino battery monitor, including:

With just a little bit of time and a few common components, you'll have your own Arduino voltage monitor up and running in no time!

Parts and Tools Needed

To build the Arduino battery monitor, you will need the following parts and tools:



Most of these components are very inexpensive and can be purchased online or at your local electronics store. The total cost should be around $5 depending on what parts you already have on hand.

Circuit Diagram and Connections

The circuit for the Arduino battery monitor only requires connecting six components together, not counting the battery pack. Here is the circuit diagram:

Circuit diagram showing connections between Arduino, 10k resistor, zener diode, LCD display, potentiometer, and battery pack

And here is how to connect each part:

Be sure to connect the components correctly to avoid any issues. The resistor and diode act as a voltage divider to step down the battery voltage to a readable level for the Arduino's analog input.

Arduino Code

The Arduino sketch (code) to measure and display the battery voltage is fairly simple. Here are the key parts:

The full code can be found in the link below:

Arduino Battery Monitor Code

This code can simply be uploaded to the Arduino after installing the LCD and LiquidCrystal libraries.

Calibrating the Monitor

Before relying on the voltage measurements from the monitor, it's a good idea to calibrate it for accuracy. Here's how:

Taking the time to calibrate will ensure you get reliable and accurate results from your Arduino battery monitor. Expect accuracy within about 5% of the actual voltage.

Using the Battery Monitor

Once assembled, calibrated, and programmed, using the Arduino battery monitor is as simple as connecting a battery and reading the voltage on the LCD display!

Some usage tips:

With this cheap and easy to build monitor, you'll always know the state of your batteries!

Going Further

Here are some ideas for enhancing and expanding the capabilities of the basic Arduino battery monitor:

By leveraging the Arduino platform, you can create an increasingly complex and feature-rich battery monitoring solution. The possibilities are endless!


Building your own Arduino-based battery monitor is a simple weekend project that can give you valuable insights into your battery health and usage. With just $5 worth of common components, you can assemble a basic yet functional voltmeter that works with any battery.

Use this guide to understand the parts required, connections needed, Arduino code, calibration, and usage tips. And consider the many options for enhancing your monitor as you gain experience. With DIY Arduino projects like this, you'll be able to create customized, professional-grade devices on a budget!