I know you can test your fan motor bu using a 12v power source but what would work best? the source im talking about.

 

a car battery works good.

 

haha...

couldnt you wire together a couple of batteries (6v, for example)to add up to 12v too?

 

You need amps capacity as well as voltage. Wire up a few batteries, but only if they're big enough to supply the required amps. Eight AAA batteries in series produce 12 volts, but that won't be able to supply enough amps.