Doesn't go to the battery. The cable from the starter motor goes to one terminal on the "solenoid switch" relay. This high current relay (notable for its 6mm stud terminals to handle that current) is under a side panel, usually the left side panel. The battery cable (red to +) goes from the other relay terminal up to the battery. The cable route from motor to relay depends on model but basically snakes behind the engine cover and exits with the rest of the engine wires. Some models connect the harness power feed to the battery terminal on the relay, some connect it directly to the battery + terminal.