Sorry, but I have to ask the dumb question: Are you trying to charge via your computer? Because, while the iPad does charge that way, it's a tiny, tiny trickle ... which can take forever.
The best way to charge is via the official Apple iPad charger (and iPad cord!) via the wall socket.
If you ARE charging via the wall - are you using the proper iPad charger and cord? Lots of folk have reported issues if they are not using both the charger and the cable for the iPad.
Let us know if this helped.
Marilyn