Battery voltage monitor with NodeMCU Esp8266-12E WiFi module
boost - NodeMCU power via battery + battery charger + booster - Electrical Engineering Stack Exchange
IoT Based Battery Status Monitoring System using ESP8266
One ESP8266, One Battery, One Year… And Counting. | Hackaday
ESP8266 ESP32 Power Supply Dual 16340 Battery Charger Shield Module For Arduino | eBay
I recently finished the prototype for a battery powered ESP8266 based temperature and humidity sensor with eInk display. Currently working on a custom PCB. : r/arduino
lua - Check the battery status with NodeMCU? - Stack Overflow