You might consider attaching a portable solar panel charger kit to your bag and using it to charge a USB battery pack in your basket:
Any maker of these panels:
https://www.amazon.com/BigBlue-Charger-Foldable-Waterproof-Compatible/dp/B07ZQXPP17/
Connected to any maker of power bank batteries:
https://www.amazon.com/Anker-Ultra-Compact-High-Speed-VoltageBoost-Technology/dp/B07QXV6N1B/