Battery drop from 50% to 15% every time

Bad to here.
Can you give us a short timeline of the develoment?

e.g.: Notice of battery level jumps on .[…date…] --> Spin-test=negative on […]–> more problems (like…) on […]–> spin-test=positiv on […]?

Would help for others to figure out the development of symptoms to a bloated battery…thanks a lot!
Cheers, Robert