Why isn't my battery charging?

I opened the tablet up, disconnected the battery wire (just used a small blunt object underneath and popped it up), took the battery out and waited a minute. Put the battery back in, connected the wire back on, put the backing back on the tablet and plugged it in. It worked. There are tutorials on youtube on how to replace the battery. Although I was not replacing the battery, simply just re setting it, that's how I got mine to start charging again. Good luck.

My tablet is charged when I take out cable the charging goes low tal me what I do

You should try changing outlets. If it doesn't work...