Xiaomi wifi amplifier can be plugged into any USB-powered device, such as mobile phone charger socket, charging bank, computer USB interface can be used, as long as the output current in the range of 1A voltage 5V can be used.
As you said during the trip, the main millet wifi amplifier is paired with a router, such as carry-on routing, but it must be within the signal coverage range, in general, like the front and back of the bus, it should be covered. The rooms in the accommodation should also work perfectly.
I hope my answer can help you.