amp overheating

So i recently got a fan to put with myy amp to make it not overheat...it was a cheap walmart fan that plugs into the cigarett lighter and it worked great but i decided to hook it to a battery i have in my trunk, and it doesnt seem to be blowing as hard, i was wondering if it reversed the fan because it feels like its blowing from the back instead of the front.... so the question is if i hooked it up to a direct power source like the battery would it reverse the fans? please help

So your saying you cut off the dc plug and straight wired it correct? If so double check the voltage input on the fan, it is possible to the plug regulates at a different voltage at 5,7,or 9volts, also check the polarity of the fan, an easier way to install these are grounding then use the positive wire on the remote/amp turn on lead.Chadillac

If the fan is blowing in reverse then most likely you wired it backwards. Try flipping the power wires around and see if it blows in the correct direction.