Add battery charger to ESP8266 and ESP32 (well done) - eMariete
Amazon.com: HiLetgo ESP32 LCD WiFi Kit ESP-32 1.14 Inch LCD Display WiFi+Bluetooth CH9102 USB Type-C Internet Development Board for Arduino ESP8266 NodeMCU : Electronics
IoT Lithium Battery Monitoring system using ESP8266 & Arduino IoT Cloud
Utilizing BSI on a Samsung S3 Battery - General Electronics - Arduino Forum
Running NodeMCU on a battery: ESP8266 low power consumption revisited – Tinkering with Technology
Esp8266 Esp-01s Esp01s Serial Wireless Module Wifi Sensor (esp8266 Esp-01 Updated) For Arduino Wifi Module Advanced Version Diy - Replacement Parts - AliExpress
ESP8266 Wi-Fi Module Battery to Use - Microcontrollers - Arduino Forum
ESP8266 Voltage Regulator For LiPo and Li-ion Batteries | Random Nerd Tutorials
ESP8266 Voltage Regulator For LiPo and Li-ion Batteries | Random Nerd Tutorials
Amazon.com: MakerFocus ESP32 Development Board WiFi Bluetooth Support Integrated 2.4GHz PCB Antenna CP2102 with 0.96” OLED Display for Ar duino NodeMCU Intelligent Scenes : Electronics