Voltage fluctuation = Alternator?
Thread Starter
6th Gear
Joined: Aug 2004
Posts: 6
Likes: 0
From: Charlestown Indiana
Voltage fluctuation = Alternator?
Driving home from work today I noticed the dash lights kinda flicker and dim and the RPM’s drop when I slowed or stopped at lights. It seemed to run strong on the highway. I recently changed the battery so I started monitoring the voltage and it was jumping all over the place. Hitting from as high as 15.2 down to 13.4volts. Wondering how accurate the car was I put a meter on the battery when I got home. 12.1 before start, drop to 10.6 at start and then stayed around 13.7-13.9 while running. The voltage display in the car did jump around a little but nothing like it did while I was driving it home.
My question is - could this be the alternator going bad or could I have spiked something changing the battery out? It’s a 96 and everything is still all original with about 46k miles.
Thanks
David
My question is - could this be the alternator going bad or could I have spiked something changing the battery out? It’s a 96 and everything is still all original with about 46k miles.
Thanks
David
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
The alternator voltage regulator attempts to maintain 14.7 volts across the battery all the time. The voltage will be 14.3 cold and 13.3 hot. There is 0.3 volts across the ignition switch contacts. If the voltage was jumping around, it should cause your instrument lights to change brightness in step with the voltmeter. If not, you have a poor connection to the dash voltmeter.
