One ESP8266, One Battery, One Year… And Counting. | Hackaday
ESP8266 Voltage Regulator For LiPo and Li-ion Batteries | Random Nerd Tutorials
ESP8266 Development Board Battery and Solar Powered with OLED display Sensor integrated, LDO voltage regualtor and Battery Monitoring System - Share Project - PCBWay
reset - Resetting of NodeMCU ESP8266 in deep sleep - Electrical Engineering Stack Exchange