What Voltage Should an Alternator Put Out at Idle: 13.8-14.4v
Quick Owner & Driver Verdict Expect 13.8 to 14.4 volts at idle on most gas-powered vehicles with the engine warm and accessories off. Readings below or above that range deserve a closer look at the charging system. If you’re asking what voltage should an alternator put out at idle, the practical answer for most cars…