You can use the YouTube app on your phone. In fact you can use any video app you want. Just go through the App Mode screen and hit the ignore button to launch the App radio app. Then open the app you want from the phone.
I have not issues with my iphone just in this case power of charge = power of discharge (not everytime, but sometimes it is). For android there is an app called "screen standby", which turning off the display of android phone and I think it's good for the screen.
Which unit do you have? I have no issues charging.