DC fans reversed

If some run right and some run wrong... it wouldn't hurt to check the battery hookup to be sure but just reverse the polarity on the motors that run the wrong direction. Flipping the blade doesn't reverse the flow! If the blades have a curve built into them, they won't flow nearly as much as when they are running correctly but the flow direction will be the same. Curved blades need to scoop the air just like a spoon scoops ice cream. Something like a fantastic fan has a twist in the blades but no curve or scoop cuz they are bidirectional... they need to blow equally in either direction. There are CW and CCW blades and that's what it takes to reverse the flow with a non-reversible motor... change to the other direction blade. Craig