My conclusion after trying to get my charge 5 back working, spoiler alert, nothing worked. So I get the black screen and no response as if the battery is drained, plug into the charger and the logo flashes up followed by the battery status screen that says it is fully charged. Went through all the options with Fitbit help/customer service, eventually got offered 35percent on my next Fitbit as nothing works. With a bit more messing about I realised when it's connected to the charger I can swipe the screen and get to all the menus so I go to the reset under settings, when it powers back on I get the Fitbit logo and then the battery status screen but this time it says 0 percent and shows the red glowing outlines like its charging. Unfortunately this only stays on for about 3 seconds and gets replaced by the 100 percent charged battery status. So my conclusion is that there is a problem with the battery software that's kicking in with 100 percent charged and so not charging the battery so when you take it off the power supply it just dead.
