Hi @brian94461
Lithium batteries have be known to fail of their own accord and not due to any other reason.
Replacing the battery is the best option.
Here's a [https://www.youtube.com/watch?v=wKjt7gCyWiU|video] that shows what to do.
Search online for [https://www.google.com/search?client=firefox-b-d&q=BN5D+battery|BN5D battery] to find suppliers that suit you best. (examples only)
''Remember to dispose of the faulty battery responsibly. The environment will thank you for doing this.''