Design and develop battery packs for your robot Part -01

A battery pack or portable energy source is an essential component in robotics. If you’re enthusiastic about robotics, this article is for you!

Let’s dive straight into today’s topic.

When designing a battery pack for your robot, it’s crucial to consider key design parameters such as the allowable weight, maximum power requirements, desired voltage, and required current based on the power demands. First, let’s discuss how to determine the battery pack voltage.

The voltage of the battery pack depends on the components and microcontrollers you plan to use. For example, if you’re working with Arduino and Raspberry Pi controllers, 12V is generally optimal for these components. So, let’s proceed with an assumed voltage of 12V.

Next, you’ll need to determine the maximum power required by the robot. For instance, in my experience with an autonomous underwater robot project, a single motor drew more than 10A while operating underwater. Let’s say it drew 15A. With six motors on the robot, and assuming they all draw roughly the same current and operate simultaneously, the total current would be around 90A. Adding an additional 10A for other electronic components brings the total peak current to 100A. To ensure accuracy, refer to manufacturers' datasheets for the current ratings of each component.

With the peak current established at 100A, the next step is to calculate the energy needed from the battery pack. This depends on the desired operational time of the robot. For instance, let’s assume the robot needs to operate underwater for 15 minutes. Since we know the robot’s voltage and current requirements, we can use the formula $P = VI$ to find the power: in this case, 1200W. Power (W) represents joules per second, so by multiplying by the number of seconds (900) in 15 minutes, we calculate the total energy required as 1080 kJ.

Now, to determine the battery capacity, we can express it in either ampere-hours (Ah) or watt-hours (Wh). In robotics, Ah is commonly used, though Wh can also be suitable.

To find the battery capacity, we need 100A for 0.25 hours (15 minutes), so we’ll need a battery pack with a capacity of 25Ah.

Great! We now know the required battery capacity for our robot. Now it’s time to design the battery pack.

Stay tuned for the next article.