Charging system

Good evening everyone, I am having some weird electrical issues. And was wondering if anyone could help. My alternator is putting out a lot of current. I have changed alternator and voltage regulators. Rebuilt the wiring harness triple checked the wiring for proper installation. It puts out upwards of 18 volts at 2000 rpm. And starts to make my volt meter pulse. The voltage regulator is grounded, any help would be greatly appreciated.