It tested 14.7-8v at the alternator at idle and 14.8 + at I'd guess 4000 rpms, at the battery it tested 14.5-6v at idle. When I called Powermaster I gave the tech the p/n for the alternator and asked what the idle output should be? after telling him what size pulleys I'm running he said 14.8v. Then I gave him what my voltage readings were and he told me that my charging system was working perfect.