Alternator and Battery Problems

I have a digital amp/batt gauge that plugs into my cigarette lighter and I have some concerns. About 5 years ago I replaced my stock alt with a Powermaster one wire hook up alt from summit. I think it is either 130 or 140 amps. So When I am driving, I am usually at 14.0-14.2. With the car shut off, I am right around 12 volts so that's good. The battery is a brand new interstate.

Here's the problem. I was driving last night so naturally I turned the headlamps and fogs on and my amps dropped to 13.1-13.3. I stopped at a light and at idle, it dropped to around 12.5 amps!

This is not good. Is my alt going out or is this normal. I just pulled my car out of storage and do not remember it doing this before, not a drastic change like this dipping below 13 amps. What is wrong? Hopefully the alt is not dying.

HISSIN50 said:

i take it this was at idle? what is your idle speed? did it go back up if you raised the revs a couple hundred RPM?

if you have doubts, you can have a parts store check the system out for free.

i would charge the battery up, so you know it is good to go and clean all the battery and ground connections - after sitting all winter, they might have corroded.

good luck.

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idle speed is around 650-750 rpms. I should bring it in and have it checked out. I just thought that it sounded low at 12.5 amps.

I will clean off the posts and terminals. I just replaced the terminals last year, but hey with a MN winter anything can happen. Thanks fellas.