8. We routed it around the back of the head and down to the starter. With that, we fired up the car and hit the gas once to bring the rpms up to about 2,500. The one-wire design doesn’t use a sensing wire, so the alternator needs to be spun up to start charging. After it started charging we had almost 14 volts at the back of the alternator letting us know this bad boy is ready to provide us with all the power we could need.