I bought a Romoss 30+ power bank during one of the recent sales, and boy, is this thing big! I've been having a look around at camera bags to transport it so that it isn't just tumbling around inside my backpack. How is everyone else carrying their giant power bank around?
I keep mine in a fat oval/egg shaped case. It's got rubber nodules all over the outside so it doesn't get damaged if dropped or thrown. A nice green/olive colour.
The charging ports are covered by a steel lever to prevent damage, and that stays in place with a handy pin with a ring.
The looks of I get on flights by fellow passengers is priceless!
https://xkcd.com/651/