Possible alternator problem?

[swordfencer]

As I was driving on a road trip the other night, I noticed that it looked like my headlights were flickering. I looked at my voltage gauge, and noticed the the needle was twitching just around 13V. It did this for about 10-15min, then stopped and went back up to around 14 and stayed steady. I then stopped at my GFs house for about 4 hours, then started the car and noticed that the voltage gauge was reading about 13V again.

Then yesterday, I had my AC on (hot day) and the headlights were on. When I came up to a stoplight, the voltage went down to 13V, then as I accelerated, it went back up to 14.

I have a stock battery and alternator, as well as everything else. The car as 20,500 miles on it. I am guessing it probably would not be a bad idea to change the battery too right?

[Dan00GPGT]

I'm not sure what your alternator is supposed to put out at idle but that 13 volts doesn't sound unreasonable if you're running the A/C and headlights. Headlights (along with tail, corner, dash, etc) can probably draw upwards of 20 amps by themselves. Add in the radio, ignition system, computers, various devices related to engine management and I would bet you'd lose a volt or so at idle. You could have it load tested but I'd almost bet your car is running normally.

[swordfencer]

Thanks for your help, I know that everything running like that does eat up a lot of juice, I just did not know what would be normal.

As for the headlights flickering and the needle twitching like it did, that is something I know is not supposed to happen.

[koolZ71]

yup 13 is about normal, now if u sit ur car at idle, and hit the accelerator, and hold it down around 3k rpms and the voltage meter doesnt move, it usually means the battery is bad, or the alternator is not charging in most cases

[Dan00GPGT]

When you say the lights flickered, did your transmission just shift? I have seen the lights dim slightly when the tranny shifts on several newer cars. That too is normal (to a point).

[nnewton123]

my voltage meter usually drops to around 13.3... 13.4 when I have the AC on and am not moving. It is pretty random though... sometimes it drops that low... sometimes it stays right around 14. I also just had my alternator check and it was putting out 103 amps with pretty much everything turned off. So I would have to agree with everyone else, that your alternator is most likely fine.

[swordfencer]

I was cruising along the freeway at 80mph when the headlights started to flicker and the voltage needle started twitching.

[2003GAGT]

Sounds like a dirty or bad ground connection somewhere...

[swordfencer]

I was wondering if it was a bad ground. I will need to dig around and see if I can find anything loose or burned.

Thanks for the help guys!

[SwtGrndAmGT01]

Ok, i was having problems with the a few lights comming on and stayin no. Specially the ABS light. Well of course it was comming on because wasn't getting neough power. I had installed a new 160amp high output alternator. Well I got the battery tested and the alternator tested and come to find out the alternator is no good. Now I am going to have to send back the alternator I got and get another one. :(