you need both batteries hooked in series to get 24v you with have one feed one pos"red" and one neg "black, connect the red to the pos on one battery the blk on the neg on the other battery and go from pos to neg with another cable on the two remaining posts this will get you 24v if you need 12v you would hook up another cable to to the neg one just from one battery and that would go to the centre pin you will get 12v from one pin to the centre pin and 24v from the two outside pins