Charge 5 battery is draining quickly

[CConny]

Since last week the battery of my charge 5 is empty within a few hours. Before it lasted about 4 days. 
What can I do to solve this? 
Switching off did not do the trick.

Moderator Edit: Clarified subject

[SunsetRunner]

A firmware update caused the issue for me. My Charge 5 was ultimately  bricked as a result of using Fitbit's "fix" instructions and has remained a boat anchor for at least 3 months. I refuse to spend money with a company who doesn't support their product. I cut my losses and bought an Amazfit Band 7. I am only here to watch developments on a real "fix" or an offer to send me a new Charge 5 because a firmware update bricked it. Fitbit/Google appears to be unconcerned about replacing the thousands of Charge 5s (and other models) that they screwed up. 

[7802]

Have had my Charge 5 for 5 months and battery has died.