Galaxy S6 Android Nougat won't charge and battery is dead

[AC Question]

Hi all,

I left my S6 charging all night, something I rarely do, but did so as it was completely flat and is now taking about 90 minutes to charge. It's one year old and I'm starting to see some battery performance issues but nothing too serious.
When I went to it this morning, it was almost totally dead. I was able to switch it on but by the time I enter the SIM PIN it just dies again. I use the charger that came with it and have tried a different charger and socket. I also tried charging it from my PC - same result. I don't know why but I don't think it's a hardware issue, usb port or battery even though leaving it charging for 8 hours may have something to do with it. Is there anything I can do before bringing it for repair and being without it for a few days?
It was upgraded to Nougat from Marshmallow a few weeks back (hate the upgrade) and the battery has suffered since but nothing serious

 

[Tim1954]

You can sometimes resurrect dying batteries by giving them a big boost under controlled conditions, but that takes special chargers etc.
Sounds like you may need to replace yours....