Quote Originally Posted by skeyo View Post
Bud take it easy. It's not that easy to calculate. Every fan has peak current when is turned on so that's why it's uses more power. So you can easy burn your fan controller. Most of controllers have over current protection but for 24/7 use sometimes is not good to use them on their limits. So there is no reason for anger.
His fan controller probably has a peak current rating as well. Look at the datasheet of any power transistor or fet. they have peak ratings as well.

If the OP wants to get technical, try to find out the transistor/fet that is used for the each channel of his fan controller, and find the datasheet. The fan controller manufacturer might just underrate their max current rating. never know, unless you look at a datasheet ;p