Battery Life Calculator - How long will it power a circuit? mah

The video tutorial explains how to interpret the milliamp hour (mAh) rating of a battery, which indicates its capacity to provide current over time. It discusses factors affecting real-life battery performance, such as internal resistance, age, and temperature, which can reduce the expected lifespan. A formula is provided to estimate battery life by dividing the battery's capacity by the circuit's current demand, though actual performance may vary.

Explain the formula used to calculate battery life.

Why might the theoretical battery life not be achieved in practice?