IoT based Battery Monitoring System using NodeMCU and ThingSpeak
ESP8266 battery level meter | ezContents blog
IoT Based Battery Status Monitoring System using ESP8266
ESP8266 Development Board Battery and Solar Powered with OLED display Sensor integrated, LDO voltage regualtor and Battery Monitoring System - Share Project - PCBWay
Battery voltage monitor with NodeMCU Esp8266-12E WiFi module