Tech Note 109 - ESP32/8266/Ardiuno Project Power Source
Using a single 18650 cell, this unit provides three 3.3v and 5v outputs. It has a Type-A socket providing USB power and has comprehensive battery charging and protection circuits, all for £1.80.
Add a 5 or 6v solar panel and you have an autonomous power source for your projects.
Examples here: https://www.aliexpress.com/item/ESP32...
Product: https://www.banggood.com/Wholesale-Ar...