Samsung's s9 phone supports up to 15 watts of fast charge, it can use two charging specifications, one is 5V\/2A but only 10 watts; The other is 9V\/1.67A, which is 15 watts, and using the latter is fast charging. The s9 uses the QC2.0 fast charge protocol, which is an older one, and the current Samsung's new mobile phone S20 supports the QC4.0 up to 25 watts of fast charge power.