1 wire alternator problems in Electrical, Lighting & Electronics Posted October 26 Well above 2K... Like I said, been through 3 alternators. They all have charged at 14+ volts upon initial install and stay there with all the lights, wipers, A/C, electric fans, and stereo on. They will perform flawlessly for a couple thousand miles and then one day just drop down to 9-12v and stay there. None of them ever go to zero. Voltage checked on the Alt. stud with a multimeter as well as confirmed on the aftermarket dash mounted voltmeter.