After the original charger is fully charged, the phone uses the electricity from the charger without consuming the power of the already full battery. Many non-original chargers should be fully charged will automatically disconnect, and the device always takes electricity from the battery, when the battery power is consumed to a threshold value (probably 99.9% ha ha??) The charger continues to connect to the power supply to charge. However, I even use the original charger is rarely fully charged, that is not good for the battery, for the lithium battery should be less loss or full charge, I generally charge to 80% on the plug, listen to the big guy said that the battery loss is less.