It doesnt really matter if you set it to 30 watts, the max ohm set for the .5 coils is .71 which it reaches within seconds and then is limited at 19 watts, then the device lowers wattage to around 13 to stay below the max .71 ohm. I have not tried to increase the max because I dont want to fry a coil. best thing to do to get a get idea of the max settings is to watch the device logger, its pretty cool