its not supposed to be much but it is two fans and both fan power wires have to get 12v to spin hi-speed , i dont think the adapter lets you go high speed
i have the racetronix hotwire on both my cars which have 30A fuses (1 for lowspeed , both for high speed ) and have had one of my fuses blow twice , i have since replaced it with a 30A slow blow and its been holding just fine .
the fact that i blew a 30A fuse makes me glad i went to the hotwire setup to take all the load off the factory harness rather than have the original fusible links burn up.