It sounds like what you want is a USB Power Bank. Specifically, you would power your usb hub via the power bank, and run whatever you needed powered through the hub. The power bank would also allow you to utilize a more stable DC current, compared to the AC coming from the wall.
Here's a power bank suggestion that should work:
https://www.amazon.com/Portable-Charger-Anker-PowerCore-20100mAh/dp/B00X5RV14Y/ref=sr_1_4?s=wireless...
Hope that helps.
Here's a power bank suggestion that should work:
https://www.amazon.com/Portable-Charger-Anker-PowerCore-20100mAh/dp/B00X5RV14Y/ref=sr_1_4?s=wireless...
Hope that helps.