I never had this problem or as bad as some users but I have notices a few things to keep an eye out for
When you plug your tab into the charger do this
Go to settings - Battery and make sure it says Charging (AC) , on a few very rare occasions I found that sometimes plugging it in it wouldn't switch over to charging (it would still say discharging even though it was pulling current from the charger) and required a reboot I suspect this could mess up battery stats pretty bad, another way to tell is when you plug it in, shut the screen off for a second or two, then press the home button or power button and make sure it says Charging xx% on the unlock screen.
another way to charge is just power it off (power button for 5 seconds, select power off on the popop menu) plug it in and you will see a big battery charging animation, you can regularly check updates by pressing the home key or power key...
Oh and toggle off WIFI (found out wifi can pull an additional 100mA when tablet is in standby), bluetooth(not necessary unless you were using it), and GPS before charging.
