Also to know is, what does a black battery symbol mean on an iPhone?
When the device is unplugged and running on battery, the icon is black. When you plug it in, it will change to green to indicate it is connected to external power.
One may also ask, why has my battery icon changed Colour? A yellow battery icon means that your iOS device has Low Power Mode enabled. Go to the Settings app and select Battery. You can then toggle Low Power Mode on and off. Low Power Mode is useful when your battery level is low and you want to prevent it from completely dying before you are able to access a charger.
Then, why is my battery icon black instead of green?
A green battery icon on an iPhone indicates that the battery is charging. This is a power-saving mode that activates when your iPhone falls below 20% battery life. The icon may be black instead of green if you move to screen like the settings menu where there is a light background.
How do I get the battery color on my iPhone?
Your iPhone battery is yellow because Low Power Mode is turned on. To change it back to normal, go to Settings -> Battery and tap the switch next to Low Power Mode. Low Power Mode turns off automatically when your battery level reaches 80%.