I seriously doubt its the battery cables. If the insultaion was frayed to the point where its rubbing on the frame (which is a problem on some of these cars) you would have a catastrophic faliure (AKA exploding battery, melting wires, fire or all of the above, and a nice light show too) If the cables were corroded, the battery would not be dead, but may seem dead. You will drop voltage through the cable. To check that all you do is take your digital volt meter, and check from one end of the cable to the other. from connector to connector you shouyldnt loose more that 1/10th of a volt. ground connections you are allowed a little more. Ive seen a battery cable drop anything from 2 volts to all 12 volts!