I have the same problem, but it seems like at some point the charger plug that goes inside charging port starts getting too small for the port, in other words I wonder if the port becomes wider or loose overtime. Try "wiggling" the plug inside the port and see if at some point the little battery icon at the right bottom corner seems to get any charge. My make false contact because of the situation I just explained.
I thought my tablet was bricked. It wasn’t. I had notice that it wouldn’t let me do anything anymore. It stopped charging the battery. when it loaded to the home screen it just wouldn’t respond when you touch it. My thought was okay the battery is 3 years old and it’s probably bad. So I went out bought a battery and installed it. I let it charge overnight. When I got up the next day it still didn’t charge. I reopen the tablet and trace the power back to the battery. There wasn’t anything wrong. So I decide to fix the software then I will go back to look into the battery. I had to put the image software onto the SD card then force it to restore through the SD card(power and volume up will restore from SD card). Once I did that boom the battery started to charge again. So I really didn’t need to buy the battery in the first place. . So the moral of the story is fixed the OS first. Also make sure you rename the image fill in order to install the image that is on the SD card. I hope this helps other out because i never found anyone else with this same problem.