My iPad 3 takes three or more hours to charge fully. I've turned the brightness down and clean up the open apps daily. Do I have a bad unit, or is this a rotten piece of crap? In addition it won't last through a 4-hour seminar.
From my experience you have a bad one. I have an iPad 3 and battery life has been amazing. I use it all the time and even have forgotten to charge it overnight and have gotten a second days worth out of the battery.
Honestly, I would have it looked at it. That does not sound right.