ESP8266 Wireless Dev System - Non-Battery Version from BurgessWorld Custom Electronics on Tindie
GitHub - tzapu/DeepSleepDHT22: Battery Powered ESP8266 WiFi Temperature and Humidity Logger
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
Diymore Wemos Mini D1 Esp8266 Wifi Wireless Nodemcu Module Development Board 18650 Battery Case Esp-wroom-02 For Arduino - Integrated Circuits - AliExpress
ESP8266 Development Board Battery Powered and Solar Powered - Hackster.io
Seven Pro Tips for ESP8266 : 9 Steps (with Pictures) - Instructables