The system shouldn't exceed 15 volts. If the battery tests out okay and you are mechanically inclined, you can replace just the voltage regulator inside the original 1984 alternator. A replacement regulator should cost aprox $30.
Bad voltage regulator
If the battery checks out okay, you can replace just the voltage regulator inside the alternator.
Your car should produce about 14.4 volts from the alternator when the engine is running. If it does not produce anything over 12 volts, your alternator is not charging and you need to get it repaired or replaced.
check charging system voltage it should have 13.8 ---14.3 volts it alsocould be a bad diode in your alternator most times a new alt does the trick
alternator is bad........ my best guess.... or your battery is surface charging and cant take a load....... go to an autoparts store like advance or autozone n have them check the charging system and battery. -Jarrid-
Check pigtail connection at alternator (possible loose), or voltage regulator going out in alternator, take to autozone or other and have tested, replace.
Check the voltage at the battery with the engine running. It should read from 13.5 volts to 16 volts. If it reads lower than 13.5 volts the alternator is defective.
The alternator is not charging or not charging enough.
If the alternator is not producing 13.5 to 15.5 volts it is defective and needs replacing.
The CURRENT is actually AC coming Directly from the Alternator. A voltage regulator/converter then takes it to DC. For all practical purposes, a typical automobile operates on 12Vdc. The Alternator actutally puts out about 14 Volts to allow for constant charging of the battery.
Start the car and rev it to at least 1500RPMs. Use a voltmeter to test the voltage across the two battery terminals (under the back seat). If it tests out at around 13.8-14.5 volts the alternator is working. If it tests out at 12.6 volts or below the alternator isn't charging. If it tests out above 14.5 volts the alternator is charging, but the voltage regulator isn't working correctly.
Normal charging range is 13.0 to 14.5 volts
Have your alternator tested it sounds like it is not charging.