Agreed. However, the nominal output voltage of the charger must be consistent with the nominal voltage of the mobile phone, otherwise it will not work.
The 55-watt charger refers to the rated power of the charger is 55 watts, and the 30-watt mobile phone refers to the rated power of the mobile phone is 30 watts. They don't have much to do with charging.
When charging a mobile phone, it should be noted that the nominal voltage of the charger must be equal to the nominal voltage of the mobile phone.
Use a 55-watt charger to charge a 30-watt phone, and the charging head will select the corresponding current and voltage according to different charging protocols on the phone