Description

Simple watchface that predicts battery life and charge time, and shows battery charge history.

Charge and Discharge rate estimates are saved to persistent storage, and are re-calculated based on actual battery usage. This is done passively as the watchface is in focus: no background workers or wake events.

The graph shows historical discharge data in thin lines, the current discharge curve in a thick line (starting at the left with the most recent charge), and an estimated battery charge projection to the bottom-right.
Battery percentage is sampled every 6 hours, or whenever the battery drops at least 10%. 59 samples are stored on-watch, allowing for over 5 complete charge cycles to be used when calculating the estimated rate.

While charging and the watchface is active, it will give an estimated time until the battery is full. This is updated as the battery charges to give a better estimation, and the charge rate is also stored on-watch.

Please allow at least 1 day with the watchface active to calibrate the estimated rates. You can use other watchfaces between samples, just remember to open BattMan at least every 24 hours (or 2 times per day), or when you charge your watch.

Screen updates once per minute, or when battery percentage changes.