As long as your battery pack supplies 5V/3A , yes then you could support any of the range Beryl or below however the Beryl power consumption is <7.5 W, so theoretically your battery pack would run out almost 4 times as quickly.

Heck you could run a B2200 on a 5V/3A powerbank but with <15W draw, it would only last 1/7th the time a Mango or a Shadow would.

Worth noting that the unit may actually try to draw a bit more power with a tethered device as it will try and charge the device at the same time.

Depends on the capacity of your powerbank and how long you expect power to be out.