Another post for battery nerds...
TL;DR: I tried to make the battery consumption very slow and steady, so I think the fluctuations in the graph are because my watch has poor calibration for how it reports battery percentage levels based on voltages. Some "percent ticks" seem to have a lot more energy in them than others. Combining and scaling two runs at different burn rates shows how these variations seem to correlate.
I patiently ran two baseline tests on my 2+ year old FR255, discharging from 100% down to 10% indicated charge:
- Bluetooth OFF and WHR OFF: ran for 20.21 days
- Bluetooth OFF and WHR ON: ran for 16.83 days
This is about as efficient and steady-state as I think the watch can operate, outside of battery saver mode. Iit is always tracking steps and floors climbed and showing my custom (but efficient) watchface running 24/7. My watchface also had embedded logic to capture the battery metric changes by monitoring it every 5 minutes and logging it, so at the end I could trigger it to graph the apparent consumption rates.
My charts are apparent consumption rate (percent per hour). The Y axis is log10 ruled, but labeled as % per hour values. The three colored bands are: the ranges 0.01 to 0.09%/hr (blue); 0.1 to 0.9%/hr (green); 1 to 10%/hr (red). It never goes into the upper band since these baseline tests do not use GPS.
The charts look like step-functions because I monitor each 1 % "tick" of the battery metric, calculate the rate based on the elapsed time since the last tick, and render it as a constant rate for that elapsed period of time. The charts are scaled so they fit the chart width. They represent different lengths of time as per above, in each case to burn down 90% of the battery.
My watch hangs around at indicated 100% for quite a while, making that seem like a low consumption rate. It's not too crazy for the range 99% down to 35% or so, but gets into a funny section that alternates between different apparent rates, then seeming to have higher endurance again around 18%->12% before swinging back to a rapid discharge rates.
Here are the individual runs so it is easier to see some of these funny details...
