Why won't my my Galaxy Tab 4 charge completely?

[AC Question]

my galaxy tab 4 won't charge completely

My tablet that I just got Tuesday (October 28 2014) stopted charging to 100?!

2 nights ago I let it run to 2 % and then charged it for nine hours while I was asleep and I woke up to find it was only 86% charged, the next night it was only 70 something. Then today I charged it for like 3 hrs when it was like on 74% and it made it to 81%...

Note: I did have a usb extendor attached, but took it off last night when I charged it....
Please help... is the percentage lying? Or what?

 

[B. Diddy]

Re: my galaxy tab 4 won't charge completely

Welcome to Android Central! Are you plugging it into a wall outlet or a USB port? Have you tried plugging it into an AC wall outlet, powering off completely, and letting it charge up for about 12 hours?