errrr- did you say 18A or 0.18A?
If it's 0.18A, then you're only pulling about 43W which is barely more than a fast harddrive and it should work on your system.
Again, you only get 12V out of the power connectors...
Running it at 12V might work but it'll be much slower and draw about half to 2/3 the power
Eric