Today afternoon I did fully charged my phone battery and did restart my phone cuz I had to change sim card. I kept it unused til this evening (3 hours long) and the phone vibrated. I checked and found the battery warning with 9% left. I was like the ****? I had no charger so I let it go off by itself. After coming b home, I put it on my charger, the phone wakes up and shows 87% battery. Now again, the ****? Has anyone ever face this?