# Charge Gently

Charging Li-ion batteries to their full capacity has a significant impact on their lifespan. If possible, it is good practice to charge more often, but only to a certain lower capacity.

The first stage of charging Li-ion ends at ~80% capacity when the charge voltage reaches its peak*. When that happens, the watch will buzz twice every 30s to remind you to disconnect the watch.

This app has no UI and no configuration. To disable the app, you have to uninstall it.

New in v0.03: before the very first buzz, the average value after the peak is written to chargent.json and used as threshold for future charges. This reduces the time spent in the second charge stage.

Side notes
- Full capacity is reached after charge current drops to an insignificant level. This is quite some time after charge voltage reached its peak / `E.getBattery()` returns 100.
- This app starts buzzing some time after `E.getBattery()` returns 100 (~15min on my watch), and at least 5min after the peak to account for noise.

\* according to https://batteryuniversity.com/article/bu-409-charging-lithium-ion assuming similar characteristics and readouts from pin `D30` approximate charge voltage