Exactly have the same problem, I'd like to ask first, are you rooted? What rom are you using? Because that could be the issue, I'm rooted and I'm using nolekat rom. It takes me 10 hrs or more to fully charge and it drains half the time fast. The percentage on the battery jumps higher then goes lower and it decreases while I'm charging and using it and I'm not doing anything heavy. I already tried using the battery calibration app which most people recommend to troubleshoot first, it didn't work for me. I suggest that you try calibrating first and if it doesn't work, reflash your current rom if you're rooted, if you aren't, it could be your charger and I also know my charger isn't faulty. Last thing I'll suggest is try manually removing your battery for 5mins then put it back in. I haven't tried that yet, I need the tools still. Hope this helps and let me know what you've done.
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