Power ESP32/ESP8266 with Solar Panels and Battery | Random Nerd Tutorials
ESP8266 Battery Voltage Monitor Simple – Hilo90mhz
IoT based Lithium Battery Monitoring System using ESP8266
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
Power ESP32/ESP8266 with Solar Panels (includes battery level monitoring) – EmbedGyan Blogs