ok thanks for the help il order 2 sets of those and look up how to connect a series circuit.
EDIT:
actually i found these:
http://cgi.ebay.co.uk/NEW-12v-700Mah-Re ... 518e0fecce

their only a fiver each but do you guys think their reliable?
i proberly will stick with 2 on each motor (making the 24v that the motor requires) but im guessing a normal speed controller may not take that kind of voltage? im so what speed controller should i buy?