3 W's of smartphone power consumption: Who, Where and How much is draining my battery?

With 6.5 billion smartphones in use worldwide, each relying on a battery for key subsystems like display, compute, and cellular connectivity, previous studies on power consumption often used invalidated indirect estimates that failed to isolate specific hardware usage. We address this by utilizing Google's On Device Power Rails Monitor (ODPM) tool for precise power measurements of individual components. Our findings indicate that connectivity (Wi-Fi, 4G/5G) and screen display are the primary power consumers, as shown with the Google Pixel 7A. We also confirmed similar power consumption trends using an energy estimation method on the Samsung S23+. Given the prevalence of smartphones, we discuss the challenges and opportunities for optimizing power usage.