The only difference between 15W and 18W is that the current power of the two is different. 18W charging is faster than 15W charging.
According to experts, the proportion of lithium battery power in smart phones remains between 65% and 75%, and the service life of the battery is initially. In daily life, it is necessary to develop the habit of charging at any time in order to keep the battery power within this range.
Power is the same current and voltage are different, the same voltage, the current is fast, you a 2a9v a 3a6v. There is no comparable voltage for different mobile phones are different, if the 6v mobile phone with 9v transformer, it is dangerous.