charging issue

[Android Question]

i have a Samsung galaxy s3 well my phone doesn't charge even when it is on charge it still dies it can only charge by one charger but then again that doesn't help me when its only a usb one i know it isn't the battery because i spent more money on a new one to it to do the same also with a charger it just constantly dies within a small amount of time witch is like 2 hours of use even when i don't use it has to be just turned on i need help understanding whats wrong also the company i'm on contract with won't take it in to look at it even with a a fault of the phone because the screen is cracked

 

[Rukbat]

1) When the phone is on, the charger isn't supplying enough power to both charge the battery and run the phone, so the net effect is to discharge the battery more slowly than if the charger wasn't connected.

2) If all you get from a fuly charged battery (charged until the phone tells you to disconnect the charger), look at the battery stats to see what's using most of the current. The screen brightness should be no brighter than you need and the timeout should be 15 seconds. The screen eats a lot of battery.

Also keep all radios you're not using (data, GPS, Wifi, Bluetooth) turned off until you need them.