I have two positive battery lugs and cant be assed to walk down the shops and get a negative one... is there actually any difference? I thought coppers copper and metals metal ... but wasnt sure if the resistance differed
thanks

 

only difference as far as i can tell are the markings, i.e. one says + one says -
Im gonna slap it on anyway me thinks!

 

Should work make sure to put a - on the negative one with a permenant marker so u dont' do anything dumb :D

 

its alright there both connected to one large red wire and one large black wire lol i should be ok

 

NO!

The positive terminal only flows one way! While the ground terminal flows the opposite way. That's why there are the + and - symbols on there!

What you can do is flip the positive terminal upside down, stand on one foot, start hopping, cluck like a chicken and say "Googly Goo Goo" five times fast without blinking while holding your breathe. That way, you can reverse the flow of the terminal and not burn down your car.

Or else, just remember to relabel the terminal so you don't accidently connect it to the wrong wires.