[Alex Jensen] wanted to build a battery-powered weather station, using an ESP8266 breakout board to connect to WiFi. However, [Alex]’s research revealed that the ESP chip uses around 70mA per ...

[Victor] ended up using a small 100mAh 3.7V Lipo battery from a tiny quadcopter for this build. 100mAh isn’t a lot, but in sleep mode, the ESP only uses about 15mAh, or about 6 hours of run time.