Choosing an SMD Resettable fuse for a 2.5 Ampere USB charger port
I would suggest a thermal fuse.  Powerbanks need to have a power source capable of handling its inrush starting current.   

To avoid thermal problems with the supply you can choose a tiny SMT thermal fuse.

I might choose a 2A thermal resettable fuse.  This means the MUST hold current = 2A MIN. and the MUST trip = 3.5A MAX. but it may trip at any current between 2A &amp; 3.5A or lower if enclosed and higher if soldered to a heatsink.  The polyfuse runs from 85'C to 120'C during protection mode.

https://www.digikey.com/product-detail/en/bel-fuse-inc/0ZCG0200FF2C/507-1777-1-ND/4156280

They are cheap, (compared to shipping cost) so get a bunch in different ranges.