I have a Summit Racing Chorme one-wire unit rated at 100 amps. I get about 14.6 volts to the battery at idle. Notice a heavy guage wire coming from the alternator to the positive battery cable on the starter solenoid (you can also hook it up to the positive terminal of the battery instead). Do not cut the wire that you see on my hand as it supplies power to the rest of the electrical system.
Below are the wires that you get to get rid of after the one-wire conversion. Consult the wiring diagram before cutting to make sure that you are cutting the right wires. Doing this also disables your ALT dummy light but it doesn't matter to me since I'm using a volt meter anyways.