A youtuber from the Celestial Empire recorded a video in which he shows how he created a gigantic vorbank with a huge capacity himself. However, it will be quite difficult to carry.
What capacity should a voribank have to be enough for everyday use and during a long trip? 5000 mAh usually allows you to make one full charge, and you should remember that in this case, too, the battery loses its life over time. A much more reasonable choice would be to buy a 10,000 mAh vorbank, but you should understand that with the capacity of the battery the size of the device increases as well.