Optimizing Power Supply for an Arduino Car: How Many Batteries Do You Need?

When building an Arduino car, one of the critical considerations is the power supply. The type and number of batteries required depend on several factors, including the motors used, the voltage and current requirements, and the desired runtime. This article breaks down these considerations to help you choose the right batteries for your project.

Arduino Board Requirements

Most Arduino boards such as the Arduino Uno operate at 5V but can be powered by a barrel jack within the 7-12V range. This adaptability allows you to choose batteries that fit your project's specific needs.

Motor Voltage and Current Requirements

The type of motor you use plays a significant role in determining the required voltage and current.

Direct Current (DC) Motors

Common DC motors operate between 6V to 12V, depending on their size and efficiency.

Servo Motors

Servo motors generally require a lower voltage, typically between 4.8V to 6V.

Battery Types for Arduino Cars

When selecting batteries for your Arduino car, consider the type of battery and its voltage:

AA Batteries

Each AA battery provides 1.5V. For motors requiring 6V to 12V, you need 4 to 8 AA batteries in series. For instance, 8 AA batteries will provide 12V, which is sufficient for most DC motors.

LiPo Batteries

LiPo batteries offer higher voltage and are more compact. A 2S LiPo battery provides 7.4V, which is suitable for many motors and your Arduino board.

Runtime and Battery Capacity

The runtime of your Arduino car is determined by the capacity of the batteries, measured in mAh (milliamp-hours). Higher capacity batteries will extend the operational time of your project.

A basic concept for an Arduino car is to use either multiple AA batteries or a single LiPo battery pack. Depending on your voltage and current requirements, you might need 4 to 8 AA batteries in series or a single LiPo battery pack.

Conclusion

Typically, for a simple Arduino car, you might use 4 to 8 AA batteries or a single LiPo battery pack. Always ensure that the battery pack can supply the required current to your motors. This balance between voltage and current is crucial for the longevity and performance of your project.

Example Setup

For a 12V DC motor and an Arduino Uno, you could use:

For a simple setup, using 4 batteries of 1.5V AA size is a common choice. However, the overall cost may vary, and you can purchase these batteries individually. The choice ultimately depends on your specific voltage and current requirements.

Additional Considerations

The choice of battery type significantly impacts the runtime and performance of your project. For instance, higher-end LiPo batteries may last longer but come at a higher cost. Conversely, AA batteries like 9V batteries (alkaline) and transistor batteries can provide a long runtime but at a lower cost.

Lithium 9V Batteries

Lithium 9V batteries may seem like a convenient option but often disappoint in terms of runtime. An Arduino Uno can deplete a 9V battery in just a few hours, resulting in short-lived projects. In contrast, a handful of AA LR6 batteries can last 4-5 times longer than 9V batteries.

Conclusion

Choosing the right batteries for an Arduino car involves understanding your specific requirements, including voltage, current, and runtime. By considering these factors, you can ensure that your project runs smoothly and efficiently.