The difference between different wattage fast charging: the maximum current is different, the charging speed is different, and the charging power is different. First, the maximum current is different. The maximum current of 40W super fast charge is 4A, and the maximum current of 18W and 20W fast charge is 6A. So 40W super fast charge damage to the phone is still very small.
Second, the charging speed is different. The charging speed of 40W super fast charge is much faster than that of 18W super fast charge, and the charging speed of different wattage is completely different.
Third, the charging power is different. The mobile phone supports 40W fast charge with relatively high charging power. The charging power of the mobile phone with 18W is low and cannot reach the charging power of the mobile phone battery.