I don't have a real voltmeter.the voltmeter i'm using is a feature off a Pioneer HU. Im not sure how accurate this is, but it reads 12.8- 13.2..ive seen is drop as low as 12.4 when im rolling down the window more than it will roll and the lights are on. is it new alternator time??. is there any D.I.Y way to "tune up" and alternator by removing it/cleaning it or something?.im unemployed and broke right now,but def don't wanna get stuck on the freeway someday because of this. any help is appreciated. thanks .org peeps.

 

voltage ratings are when the engine is on..not idle battery.

 

I thought that it was a 12v connection to the HU...if so, those readings are normal.

 

Engine on voltage should be about 13-14V. Alterrnator should last around 100K miles.

 

Ya thats low. You should be at 13.7-14.1 At normal driving speeds. And since you say it drops even lower when using the windows, it sounds like to me the alternator is on its way out. Since you said you are on a budget tho, I would take it to autozone (or similar) first and get it tested for free.

 

they can test it without me taking it out??or do i have to pull it first..

 

i was going to the gym tonight and checked out the voltmeter function again. now it reads 13.4-13.8 which i believe is not bad for 200k. temperature seems like the main thing that gets my alt to produce less volts. it was like 90 degrees today..probably still means the alt is going bad...

 

He's getting a reading from the headunit, not a direct reading from the alternator, so does that make a difference? What i mean is, would it still put out 13-14v to the HU directly? Or would it be closer to 12v to the HU?

 

Yes, auto parts stores can test your alternattor right there without removing it from the vehicle.

 

you bring up a good point, but i think all the electronics in the car run on whatever power is being putout either by the batt 12.6 when the engine is off, or 13-14 witht he engine is on. if you read car amp specs, you'll see that they run from 12-14.4v.. some up to 17 for competition. i think my power window motor has a little more pop in it when the car is on, as opposed to off.