I’m aware there are several similar threads, but I think my problem differs from the others. It is in fact two-fold:
My Phone sometimes spontaneously reboots and my battery behaves in an unprdictable way. Sometimes, for example after charging, it seems to lose all the energy that it just gained. Today looked like this:
At some point phone rebooted waking up with energy drained to 5% from roughly around 30-40%.
then I charged it. Shortly after detaching it from the cable it reboot again an then shows an energy level of around 20%. Given the time it was quick.recharging it should have had around 70-80%.
I’ll post a screen-capture of the battery usage that I took afterwards. This is something that I regularly see.
Try cleaning the battery contacts and those of the battery compartment, with a cotton bud soaked in surgical-grade alcohol or isopropanol. Leave to dry for an hour before replacing the battery.