“For most of the projects I am building with the ESP8266 WiFi chip, I usually don’t care too much about the power consumption aspect. I for example build data loggers that are constantly connected to the mains electricity, and appliances controller which also have an easy access to power. However, in some cases, we want to build projects that are only powered by batteries. This is for example the case for a motion sensor that you will install in your home, or a data logger you would put in a remote location. For those cases, you don’t want to be changing the batteries constantly. For example, an ESP8266 chip with a standard 2500mAh LiPo battery would last for about 30 hours. Not good enough. That’s why in this article, I will show you how to significantly reduce the power consumption of your ESP8266 boards using the deep sleep mode of the chip, so you can build projects that will last for years on a single battery. Let’s dive in!”