Phone will register as fully charged but not stay charged, why?

[AC Question]

Phone will register as fully charged but not stay charged

I plug my Samsung Galaxy 3 in and it will charge overnight. Once I unplug it however it will drop to down to 50% charge or less. Once it shut down entirely. I recently switched to a blackberry charger and it will still happen but only by a percentage or two. Is it a problem with the charger, phone, or battery? What should I do?

 

[B. Diddy]

Re: Phone will register as fully charged but not stay charged

Welcome to Android Central! So are you saying that when you use the original charger, the phone reports the battery is up to 100%, but then immediately after unplugging, it drops down to 50%? And that if you use the Blackberry charger, it goes up to 100%, and then after unplugging, it just drops down to 98%?