I'm building a portable battery powered mini itx! Uses a pico power supply and I'll be using a bank of 24 5000 MAH batteries in a 4s 6p setup! It should last
Power for the Raspberry Pi Pico - Guide to using VBUS, VSYS and 3V3 for external power circuits - YouTube
Quad GPIO Expander for Raspberry Pi Pico adds battery, display module, sensors, etc... - CNX Software
Pimoroni's LiPo SHIM for Pico Adds Easy Battery Management to Your Raspberry Pi Pico Projects - Hackster.io
Powering the Raspberry PI Pico from External Batteries
Power module/battery holder for Raspberry Pi Pico
UPS Module For Raspberry Pi Pico, Uninterruptible Power Supply, Li-Po Battery, Stackable Design | Pico-UPS-B