Update Usermod Battery (#2975)

* auto-off feature and usermod rename
* low-power-indicator, voltage fine tuning, clean-up

* corrected small mistakes
* Bugfixes, added usermod logo, update readme
* minor changes, implemented change requests, optimizationz

usermods/Battery/battery_defaults.h

@@ -0,0 +1,67 @@
+// pin defaults
+// for the esp32 it is best to use the ADC1: GPIO32 - GPIO39
+// https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/adc.html
+#ifndef USERMOD_BATTERY_MEASUREMENT_PIN
+  #ifdef ARDUINO_ARCH_ESP32
+    #define USERMOD_BATTERY_MEASUREMENT_PIN 35
+  #else //ESP8266 boards
+    #define USERMOD_BATTERY_MEASUREMENT_PIN A0
+  #endif
+#endif
+
+// the frequency to check the battery, 30 sec
+#ifndef USERMOD_BATTERY_MEASUREMENT_INTERVAL
+  #define USERMOD_BATTERY_MEASUREMENT_INTERVAL 30000
+#endif
+
+// default for 18650 battery
+// https://batterybro.com/blogs/18650-wholesale-battery-reviews/18852515-when-to-recycle-18650-batteries-and-how-to-start-a-collection-center-in-your-vape-shop
+// Discharge voltage: 2.5 volt + .1 for personal safety
+#ifndef USERMOD_BATTERY_MIN_VOLTAGE
+  #define USERMOD_BATTERY_MIN_VOLTAGE 2.6f
+#endif
+
+#ifndef USERMOD_BATTERY_MAX_VOLTAGE
+  #define USERMOD_BATTERY_MAX_VOLTAGE 4.2f
+#endif
+
+// a common capacity for single 18650 battery cells is between 2500 and 3600 mAh
+#ifndef USERMOD_BATTERY_TOTAL_CAPACITY
+  #define USERMOD_BATTERY_TOTAL_CAPACITY 3100
+#endif
+
+// offset or calibration value to fine tune the calculated voltage
+#ifndef USERMOD_BATTERY_CALIBRATION
+  #define USERMOD_BATTERY_CALIBRATION 0
+#endif
+
+// calculate remaining time / the time that is left before the battery runs out of power
+// #ifndef USERMOD_BATTERY_CALCULATE_TIME_LEFT_ENABLED
+//   #define USERMOD_BATTERY_CALCULATE_TIME_LEFT_ENABLED false
+// #endif
+
+// auto-off feature
+#ifndef USERMOD_BATTERY_AUTO_OFF_ENABLED
+  #define USERMOD_BATTERY_AUTO_OFF_ENABLED true
+#endif
+
+#ifndef USERMOD_BATTERY_AUTO_OFF_THRESHOLD
+  #define USERMOD_BATTERY_AUTO_OFF_THRESHOLD 10
+#endif
+
+// low power indication feature
+#ifndef USERMOD_BATTERY_LOW_POWER_INDICATOR_ENABLED
+  #define USERMOD_BATTERY_LOW_POWER_INDICATOR_ENABLED true
+#endif
+
+#ifndef USERMOD_BATTERY_LOW_POWER_INDICATOR_PRESET
+  #define USERMOD_BATTERY_LOW_POWER_INDICATOR_PRESET 0
+#endif
+
+#ifndef USERMOD_BATTERY_LOW_POWER_INDICATOR_THRESHOLD
+  #define USERMOD_BATTERY_LOW_POWER_INDICATOR_THRESHOLD 20
+#endif
+
+#ifndef USERMOD_BATTERY_LOW_POWER_INDICATOR_DURATION
+  #define USERMOD_BATTERY_LOW_POWER_INDICATOR_DURATION 5
+#endif