How can I tell if my alternator is working? The Battery in my 67 went dead a week ago. I Checked voltage at the battery after jumping it to get it started and was at about 10 volts. Ran a jumper at the regualtor and the alternator kicked on. Replaced the regulator and am getting 14.5 volts when the car is running and about 12.5 with it off. Can I assume it's working properly just by checking the volts or should I have it tested under a load for amps?