How do I know when the battery needs to be charged? Sherlock Support August 11, 2019 15:07 Updated Follow You get a notification on your phone when the battery reaches a critical threshold. Related articles How do I charge the device? How long will the battery last? When do the 2 years of free internet connection start? Installing Sherlock to your bike Will Sherlock fit in my handlebar? Comments 0 comments Please sign in to leave a comment.