1060 plus pen not working, battery died

hi

1060 plus pen not working. pen charges for ages and still red. the tablet is working. heres what I've tried:

-uninstall and update driver

-change pen nib

- try without driver

however, if the pen is always plugged in to the charger, sometimes its working.

any solution? 

how to replace battery?

what pen to replace with the 1060 plus (8192)?

thnx