Learn how to charge your device with iOS and get assistance in solving possible problems.
Use the USB power adapter and USB-cable from the standard supplied with the device. If you are using another accessory manufacturer, make sure that it is certified by Apple. Then, follow these steps.
When the device is charging, a lightning icon is displayed next to the battery icon in the status bar or a large battery icon on the lock screen. More details in iPhone PDF manuals
If the battery is deeply discharged, the device is connected to a power source may be within a few minutes displayed a black screen or black screen with a red battery icon. Follow these steps; after each instruction retry.
If you are not sure whether the accessory, take it to an Apple Store retail store defective or an authorized service center for Apple's check, or contact Apple Support.
These devices can be displayed for a few reasons: charge your iOS device port may be dirty or damaged, charging accessory may be defective, damaged, or not certified by Apple or the USB-charger can not be used to charge devices.