Jasion EB 5 Roamer ST replacement/spare is now available. Still not supported by Jasion.

[F15maintainer]

I finally found a seller on Aliexpress who has a direct replacement available.
I just found this on AliExpress:
$276.17 | 48V 10.4Ah 12.8AH 14AH Electric Bike Battery For Jasion EB5 Roamer Ebike
https://a.aliexpress.com/_mNciONl

A direct replacement or upgrade can be sourced.