Experiments on lithium batteries have proven that shallow charging and discharging maximizes the cycle life of the battery, if the loss of charge from 0% to 100% is recorded as 1 cycle, then
* Charge to 90%, only 0.52 cycle
* Charge to 80%, only 0.27 cycle

Battery Guard can set high and low thresholds and then alerting the user when the power reaches the threshold, so that the battery maintains a shallow cycle working state.

App features are as follows:
* Light and compact App, less than 200k.
* Support text, vibration and voice alarm when the power reaches the threshold.
* Voice alarm uses TTS engine and supports custom voice.
* Backend records daily battery cycle loss and generates daily, weekly and monthly statistical charts.
* Record battery temperature and generate daily, weekly and monthly statistical charts.
* Record daily bright screen time and generate daily, weekly, and monthly statistical charts.
* Support charging and discharging details, including charts of power, temperature, current, etc.

In addition to the basic battery-related statistics, the following functions are supported.
* Support daily, weekly, and monthly screen time statistics.
* Support daily, weekly, and monthly temperature range statistics.
* Customizable notification bar icons and functions

Battery monitoring requires background operation, please refer to the help to reserve the background correctly.