That doesn't seem to hard to do. They sell the connectors on amazon. https://www.amazon.com/Magnetic-Connector-Positions-Pogopin-Contact/dp/B0DR1R9443?th=1 ht

That doesn't seem to hard to do. They sell the connectors on amazon. https://www.amazon.com/Magnetic-Connector-Positions-Pogopin-Contact/dp/B0DR1R9443?th=1 https://www.amazon.com/Magnetic-Connector-Positions-Pogopin-... Each battery should probably have their own charging circuit anyway. So the pogo pins should be 5V and ground coming directly from the USB 5V line.