So about a month ago I purchased a second hand LG G2-D802 online and for the next three or so weeks it was working great. But just last week when I was using it, it randomly just shut down. I didn't think much of it at the time, plugged it into the charger and left it overnight. Then the next day I was using it as normal, checking emails, and it did the same thing again. I noticed that the battery was at about 70%-80% at the time it shut down. Then when I tried turning it on immediately after this happened, it would reach the home screen then immediately turn off again. It's as if the phone thinks the battery is at 0% charge, so it shuts itself down. It would only turn on again when I plugged it into a charge, where it would recognized that the battery is not at 0%. There is also no telling at what percentage the battery would shutdown, as it was varied ever time, but has happened sometime during every charge. Along with this, I've also seen abnormalities with the charging and discharging of the phone, where the phones battery would fully discharged in about 1 hour, and charge up at about the same rate, which can be seen in the linked images. This has continued to happen over the remained of the week and I've tried everything I could think of to fix it; factory reboot, re calibrate the battery, uninstalled or disabled battery draining apps, but nothing has helped. I also couldn't find anything online which has a similar issue to mine. Is it as simply as replacing the battery? Or is it something else? Any insight would be much appreciated. Unfortunately, I can't link you the images.