The 15-watt fast charge is fast
Cell phone 15w fast charger power is 15w, from power = voltage x current we can know that the charging current is 3000mA, this current charger is suitable for 3000-4500mah mobile phone battery charging, the phone should be charged when the remaining power is 50%, so the 15w fast charger needs to charge 3000mAh battery for 1 hour. It takes 1,5 hours to charge the 4500mAh battery, the charging speed is not very fast, and it can be replaced with a higher power fast charger.