Default [Q] Charging issue on jellybean tablet

Hello all and thanks in advance ..Ive seem to come across a vary stange issue i cant find any info about anywhere ..mu situation is this: i charge my tablet (polaroid s8) to %60 then it drops down to 14% and will continue to charge to 100 so essentially i have to charge it %160 but if i charge to 60 it drops to 14 and it will die after the %14 depletes HOWEVER sometimes i am able to power down after the drop and when i reboot and re plug the meter will go back up to 60 but if it goes up %1 it will drop again..wondering if its a software/hardware issue or possibly a combination..please help