Postby bobtidey » Wed Dec 11, 2019 12:50 pm
5V power banks contain a LIPO battery, a boost circuit to generate +5V out normally via a USB A socket, and a charger circuit typically with a micro USB input. They are available in various capacities from 2500maH upwards.
So you can connect a standard phone type charger into the micro socket for charging, and connect the USB 5V output to your ESP32,
Note that some power banks do not provide power out while they are charging so operation while charging is important to you then check for one that does.
The alternative is to use a LIPO battery and add your own charger and boost module which can be got very cheaply.