Your watch shows a battery percentage. It does not show how fast that number is falling, how long the last charge lasted, or whether it lasts less than it used to. This app records that and draws it. SEVEN SCREENS, SCROLLED UP AND DOWN • NOW - a ring around the screen: battery now, the part the next 24 hours will use, and the time left in the middle • LAST 6 H - the closest look, scaled to the range that occurred • LAST 24 H - a full day, sleep and training and all • SINCE CHARGE - how much has been used since the last charge, with a dashed line down to zero • 7 DAYS - a week in one chart, charging periods marked • DAILY USE - one bar per day with the average marked: does it hold less than it did? • STATISTICS - per day, busiest day, charges, hours of activity THE ESTIMATE COMES FROM YOUR OWN RHYTHM Time left is computed from your own recorded history, not from a rule of thumb. Someone who records an activity every day and someone who wears the watch for the clock get different answers, because they have different histories. In the first days after installing, before there is history to measure, the watch's own estimate is shown instead - and the screen says which one you are looking at. THE HISTORY STARTS WHEN YOU INSTALL IT Connect IQ gives no access to past battery levels - there is no such API, and nothing is stored on the watch to read. The app therefore records the level itself, every 15 minutes, and the six-week chart fills up over six weeks. Every screen says so while it is still collecting, rather than showing an empty frame. ONE PERMISSION, AND IT OPENS NOTHING Reading the battery costs no permission at all. The app asks for exactly one - Background - and only so it can record while it is closed. Unlike location, sensors or user profile, that permission grants access to no data whatsoever; it is the right to be woken up, nothing more. No sensors. Nothing leaves the watch. WHAT THE CHART MARKS Charging periods sit as a band at the foot of the chart. Recorded activities sit as a band along its top. Stretches that fell faster than the rest are drawn in amber - so a steep slope and the training that ran through it line up on the same screen, and you can see for yourself whether they go together. TOP-UPS COUNT AS CHARGES A short top-up between two measurements leaves no charging mark - only a jump in the level. The app treats that jump as a charge, so the count since the last charge starts again from there. GAPS STAY GAPS When the watch is off, no measurement exists for that time. The chart shows a break there instead of drawing a line across it. You can set the recording interval to 30 or 60 minutes if you would rather have fewer wake-ups. This app is for informational purposes only.