Abstract The paper presents Open Battery, a publicly accessible platform for collecting and analyzing battery usage data from Android devices. The authors developed an app that logs battery state changes and uploads the data for analysis. Observations from 20 smartphones over three months reveal variability in logging behavior and device inconsistencies. The study introduces fluid queues as a modeling tool to stochastically represent charging/discharging patterns.... The paper presents Open Battery, a publicly accessible platform for collecting and analyzing battery usage data from Android devices. The authors developed an app that logs battery state changes and uploads the data for analysis. Observations from 20 smartphones over three months reveal variability in logging behavior and device inconsistencies. The study introduces fluid queues as a modeling tool to stochastically represent charging/discharging patterns. The model allows for improved understanding of battery behavior and supports future development of predictive tools for battery life estimation. Future work includes refining the model for level-dependent behavior and analyzing long-term battery performance degradation. Read More Read Less