power bank harms iphone?
I use the power bank to charges the phone overnight, in tomorrow morning my phone is too hot and power bank balance is over (last night its full). plz tell me what happens?
You still did not answer. What is your friend's power bank? Until I figure that out, I can't tell you want happened and if it harms your phone.
The basics are that you should only use an Apple charger or a computer USB connection to charge the device. It could be this "power bank" whatever that is, is not supplying the correct charging voltage for the phone and is causing the battery to get hot. If it is incorrect, then yes, it could harm the phone.