Build a low-cost Raspberry Pi robot: the components you'll need — The MagPi magazine
Raspberry Pi 4B/3B+/3B X729 18650 UPS (Max 5.1V 6A) with Wide 6-24V In – Geekworm
Exploring alternate methods for providing DC power to Raspberry Pi - element14 Community
Raspberry Pi 4B/3B+/3B X729 18650 UPS (Max 5.1V 6A) with Wide 6-24V In – Geekworm
UBEC DC/DC Step-Down (Buck) Converter - 5V @ 3A output : ID 1385 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Raspberry Pi 4B/3B+/3B X729 18650 UPS (Max 5.1V 6A) with Wide 6-24V In – Geekworm
Make a battery backup circuit for your Pi! #piday #raspberrypi @raspberry_pi « Adafruit Industries – Makers, hackers, artists, designers and engineers!
Running a Raspberry Pi from 6 AA Batteries - Raspberry Pi Spy