Development board ESP32 (microcontroller ESP-WROOM-ESP32) with connector for large capacity battery 18650 Li-Ion 3000mAH. The battery is located under the development board. This card is not suitable for development on seamless prototyping board (breadboard). Without optimization, the card can run for about 17 hours. By activating the Sleep Mode in the code, you can operate the card for several weeks or more. Everything depends on your program (frequency of sending data to a server …) and the type of sensors or actuators used (variable consumption) in your project.