HOW DO I REMOVE THIS?!

[doubledrat]

I'm getting 10's of 1,000s of errors from this

I feel like I've introduced a virus into my HA instance :(

nothing has a unique ID, so I can't clear things out using the UI. I'm too scared to edit the db files.

I feel so stupid for installing it in the first place.

[DrBlokmeister]

Go to the battery notes integration page and delete every device you have added:

Then you can remove the battery_notes directory from the custom_components directory. Probably you can also do it through the HACS UI.