Daca iOS 7 had to bring major changes for iDevices, then those from Apple Lossless Audio CODEC (ALAC), they thought not to disappoint us, so they changed almost everything related to iOS, including the system that tells us how to charge the terminals' battery. In iOS 7 we have a lightning bolt in the status bar that tells us that the battery is connected to a power source, in LockScreen we have a battery that charges gradually, but unfortunately the status bar no longer tells us when the battery is charged. In the LockScreen we have a 100% Charged message displayed when the battery is fully charged, but in the status bar we see absolutely nothing.
In iOS 6 Apple displays an icon like the one in the image above, but in iOS 7 you will know that your terminal is fully loaded only through LockScreen. If the battery shows a percentage of 100% for charging, you must know that it is charging, even after displaying that percentage, so you must be careful.
