LunchBox04V
04-07-2010, 07:44 PM
Hi folks. I have just recently started having a little problem with voltage. I thought I would post up here and see what you all think. Tips, things to check, smacks on the back of the head. It is all good. lol I have a few ideas though.... Here we go....('99 Legacy Wagon, L. 170x miles, and original alternator.... more on that later)
I recently changed the battery and added factory foglights and a set of PIAA Spots. It was a month after the install that I started to notice the voltage fluctuating down to 12.5v from the normal 14.1v(About January 2010, two months after the install). Now I did check after the install, and with math, and there was no change in the voltage. All lights on, and 14.1v while above 1000rpm. Amps were within limits (planned ~ 60amps as a soft limit, 90amp max rating) and it was within the 60amp limit. The voltage drop is only slightly less if I am not using the lights.... But still below 14.1v.
Well over the past few months, the volt change has gotten bigger. Today it finally got below 10.5v. The battery that I installed was a yellow top. I think that one of three things is going on. I don't know if alternators fail 100%, or if it is a slow fail.
1.) The voltage regulator is going bad.... It is the original alternator, and I can totally see it going bad now that there is an increased demand on the unit.
2.) The alternator is going bad. Same reasoning as above.
3.) Connections to the battery, alternator, grounds, have gotten loose since I was under the hood doing the lights.
I have a feeling that #3 is a good bet as a start, and costs nothing. I will start there. I understand that if I was seeing voltage below ~12.0v, the alternator is not charging the battery/system. The fact that I get up to 13.6v or so shows that it is working.... just at a diminished capacity. That is why I think it is a voltage regulator problem (which is built into the alternator if I remember....)
I don't know if the alternator system is getting overloaded/overheated and shutting down to cool, and then starting up again. However, I don't think it is this because it happens with a normal load (No lights, no radio.) Almost forgot. Turning the car off, and then back on corrects the problem about 80% of the time.
Any thoughts? Thanks for reading all this. Hope you can help.
I recently changed the battery and added factory foglights and a set of PIAA Spots. It was a month after the install that I started to notice the voltage fluctuating down to 12.5v from the normal 14.1v(About January 2010, two months after the install). Now I did check after the install, and with math, and there was no change in the voltage. All lights on, and 14.1v while above 1000rpm. Amps were within limits (planned ~ 60amps as a soft limit, 90amp max rating) and it was within the 60amp limit. The voltage drop is only slightly less if I am not using the lights.... But still below 14.1v.
Well over the past few months, the volt change has gotten bigger. Today it finally got below 10.5v. The battery that I installed was a yellow top. I think that one of three things is going on. I don't know if alternators fail 100%, or if it is a slow fail.
1.) The voltage regulator is going bad.... It is the original alternator, and I can totally see it going bad now that there is an increased demand on the unit.
2.) The alternator is going bad. Same reasoning as above.
3.) Connections to the battery, alternator, grounds, have gotten loose since I was under the hood doing the lights.
I have a feeling that #3 is a good bet as a start, and costs nothing. I will start there. I understand that if I was seeing voltage below ~12.0v, the alternator is not charging the battery/system. The fact that I get up to 13.6v or so shows that it is working.... just at a diminished capacity. That is why I think it is a voltage regulator problem (which is built into the alternator if I remember....)
I don't know if the alternator system is getting overloaded/overheated and shutting down to cool, and then starting up again. However, I don't think it is this because it happens with a normal load (No lights, no radio.) Almost forgot. Turning the car off, and then back on corrects the problem about 80% of the time.
Any thoughts? Thanks for reading all this. Hope you can help.