I am planning to use five 120 mm fans to cool my grow room but I cannot find any cheap 12 volt cell phone chargers online and the only spare ones I have at my house are 5 volts....
make sure the power adapter is 120% larger than the combined milliamps of ALL connected fans or you will run into problems.......
a cell phone charger does NOT carry enough milliamps to run even a single small pc fan.... they will work, but only for a short time, either the power supply or fan goes bad, no warning.