Alright guys, I have some serious gremlin action going on. Late last month, I had an issue with my battery not holding a charge, at all. The dumbass previous owner wired the horn directly to the battery, for whatever reason. So, I disconnected that, got a new battery, and my alternator tested. Everything is hunky-dory, right? Not so much.

Now I've got an issue with charging. Let me preface this problem by saying my alternator was tested, and is putting out 14 amps under load, which is golden. Every 5 or 6 times I start my car, I'll drive for a bit, and my battery gauge will drop from 13ish, which is where it should be, to barely 8. At 8, the headlights are incredibly dim, and the radio doesn't work. 5 minutes later, battery is back up to 13ish amps. Problem is completely irregular, I've run through all my major grounds and they look good, I replaced the hot-wire from the alternator to the battery.

Any ideas? Because, I've gotta say I'm pretty much stumped.

Thanks guys.

 

sounds like either loose connections at the alternator or loose connections at the starter. You don't have any corrosion on your battery terminals do you?

 

No corrosion. The contacts were replaced when the battery was replaced. Connections at the alternator and starter are both tight, I even clipped the wires to ensure there was fresh wire making the contact.

 

Off the top of my head here,

- you say the alternator is original? Wondering if one of the internals is going bad...maybe a regulator or something, and it just so happened when you had it tested it decided to work fine.

-Belts. Is the drive belt worn out or loose? That would cause a fluctuation in amps at different rpms.

-Is the alternator rated at enough amps for your vehicle, IE do you have a large stereo system running and lots of accessories?

 

I've had the alternator tested 3 different times, a zillion different ways, high load, low load, idle, accessories on, accessories off, lights on, lights off, in gear, in neutral, in park, brakes on, brakes off, I get the same reading every time.

The belt is relatively new, less than 5k miles on it.

I have the stock speakers, and a plain-jane cd-player.

 

i had a similar problem . mine turned out to one of the fuseable links . i had an uncovered hot post on alt. , got a spark from a wrench doing other work . cooked one of the fuseable links near the battery . there are 3 i think near the battery . red/orange color , feel along them , if you find a soft/mushy spot its bad . they can be repaired like any other wire . remember to disconnect battery first . good luck .

 

If it will do it at idle you could try to ground the alt to the bat ground with jumper cables. See if it still does it.