I have a Samsung Galaxy 4 that's a couple of years old and constantly needs recharging. When I am done with a session I shut the thing completely off. When I read (starting with a full charge) in about two hours the charge is down to about 15%.

Is there any way to change the battery or am I stuck with a very expensive paperweight? Is it time to bite the bullet again and upgrade/buy a new tablet? This drives me crazy.