A quick to print tracker mount which goes under the tracker, a string is enough to hold it in place. A double-sided velcro strip can hold any cylindrical power bank onto it.
Very quick to print, with my Ender 3 it takes about 15 minutes.
Would recommend using PETG or similar for better durability, but if using PLA you can just make it a bit thicker if you want to be safe.
VR_tracker_battery_mount.stl | 34.5KB |