HT5423: iPad: Battery safety certificationsLearn about iPad: Battery safety certifications
Currently Being ModeratedApr 4, 2013 4:47 PM (in response to C1c2)
Chargers, and the unit being charged where the battery is located, will get warm during charging...charging does work on the battery. If it is hot or too hot to handle then you need to decide if it is too uncomfortable and needs to be checked at the Apple store genius bar.
Nine hours is a long time to charge, but if you discharged all the way it can take 4-8 hours to fully charge.
If the charger is getting very hot and taking a long time to charge you may want to take it to the genius bar and have it checked by the techs.