Me. When hooking batts together, if you r hooking 2 together but only want 12v you hook it normal and then your jumpers go from positive to positive and negative to negative. When hooking 3 together to make 36v hook positive from TM to one battery then jump from negative to positive to batt 2 then negative to positive to batt 3 and the n your negative to the TM on the negative of the third batt.