Possible electrical issue or bad alternator?

[StainlessBullet]

Ok guys I need a little help here. I've had an issue with my car lately. My voltage gauge had been reading on the low side. The needle drops into the below normal area, and when I hit the throttle it bounces back up into the low normal side. If the car sits for longer than a week the battery is drained. Recharge the battery and I'm normally good to go, other than voltage gauge. While driving it this past weekend my after market radio started turning off and then back on. Then the car lights started flickering. After a few mins, everything went back to normal. Then it started again a little while later. After that my tachometer started jumping all over the place.

Where should I start? If it's the alternator, wouldn't it just go out all at once? Either I've got an electric issue or my car is possessed lol. Any help would be appreciated.

[Jonathan]

How does your alternator belt look? Fairly new? or worn a little? Is it adequately tight? Maybe it has been slipping and not charging the battery via the alternator like you think it has?

[Elvis]

a loose wire or brushes worn - I would guess and search for

[Bitsyncmaster]

You need to start with measuring the voltage with a multimeter. Measure at the "jump" terminal (red wire) to the engine block.

Measure with engine off.
Measure with engine at idle no loads.
Measure with engine at idle headlights on.

Your problem could be a bad alternator, bad battery or bad connection.

[David T]

If you have a Ducy just replace it. If you have a Motorola there are places like Auto Zone that will test your battery and alternator for free. If the battery is over 5 years old just replace it too.

[gullwinger]

My Motorola alternator did the same thing and the batt light would stay on and the volt meter read 13volts, Replaced with Hervey's alternator and no the new one wont charge and the batt light does not come on when key is on or running. Still looking for the problem, I replaced the dash bulb to the alternator circuit but still having issues. It may be a break in the Brown/Yellow wire which ignites the regulator in the alternator.