the battery will stop working.
F you over charge your phone battery It will die faster
Either your batter will take longer to charge - or - it will over-charge the battery. Neither of which are covered by your phone's warranty ! An over-charged battery can explode - possibly damaging the phone beyond repair.
This is the peak voltage for a 50% probability of flashover or disruptive charge.
faulty voltage regulator
Nothing.
defective voltage regulator
A voltage regulator converts a/c volatge from the stator to dc voltage and regulates it down to under 15 volts. When they go bad they can over charge and take out a battery as well as not charge at all.
A cell phone heats up because of the activity inside the cell phone while it's charging. The chemical process inside the battery needs to be reversed in order to charge up the cell phone and electricity is moving through the phone as it charges. Most electronic devices, if not all, heat up while being charged.
The voltage regulator is faulty.
Sort of ... 1) Voltage is ALWAYS a comparison, thus it requires two reference points. 2) Its the density of the charge that counts, thus a gigantic charge over a very large area would result in a low voltage.
If you are plugging your phone into a computer, then that is free. Downloading songs from the Internet connection on your phone often incurs a charge, and when using free MB of Internet be careful not to go over that amount.
Most RC mode-3 instances of overuse (letting the voltage drop too low) they will not charge adequately.