Xperia E5 overheating and losing charge very rapidly

[Tigrowski]

I've had an Xperia E5 for around 1 and a half years now. I had no problems with the phone whatsoever, it held charge for around 3 days under my usage but suddenly, four days ago it just became really, really hot on the back and lost charge by around 50% within two hours and then turned off. After charging it back, it lost the charge from 100% to 60% within the first hours of the next day and - again - turned off, without the possibility to turn it back on even though 60% was the last reading. I didn't change anything, install any new apps, I've always been a very casual user of that phone (Wunderlist, GMail, Chrome from time to time). No updates were performed in the past days, no new charger used.

What may be the problem? I've tried running AccuBattery on it and for example here is the reading from yesterday (lost 76% in a day of barely using it - not as extreme as the examples I mentioned above but I wasn't able to catch those on AccuBattery as it hadn't been installed on my phone back then). The readings seem fine so I'm not sure if the battery itself isn't a problem.

What do you think?

 

[Tigrowski]

No ideas what the problem may be?

 

[B. Diddy]

That behavior is common for a failing battery. Does this also happen in Safe Mode? https://support.sonymobile.com/global-en/xperiae5/kb/0231018877589a7b01429399b11c00699b/