Ipad Battery Life

[Chasingcars]

My ipad seems to shut down as if battery has run out but just prior to shutting down battery life was 30%+...
And, when i put it on charge it comes back on still showing 30%...
Sometimes it really is dead and takes 10/15 mins to come back to life but then it does and suddenly shows 30% battery life again...!
If i charge it all night to 100% by the afternoon with limited use its dead...
Any ideas?