car acting funny

[frogcase2002]

Trying to see if someone can help me figure out whats wrong with my old car. . Its a 2005 mercury sable . . It was running fine last time I drove it almost a month ago but when I went to went to drive it just now it wouldnt start so I jumped it and it started right up. Then the volts on my volt meter were going everywhere up and down. Couldnt ever tell you how high or how low cause it was going to fast. . but when I reved the motor it stayed pretty steady in the high 13s-low 14s . Then I went to see if I could dive it and it pulled off fine but then the head lights shut off and lost almost all power for a couple seconds then eveything went back to normal then it kept doing that like evey like 20 seconds so I took it back home . . . . So when it drives it acts Like its just about to die . Volts go way down. All dash lights come on and head lights turn off then goes right back to normal over and over. . . . Never seen this happen before

[frogcase2002]

Sorry if this is in the wrong section. Couldnt find where I should post something like this. but figured it mite be the alt of something electrical

[frogcase2002]

Could it be a bad battery? Figured the alt would keep it running good once it was started but been reading some stuff and thats not always the case . . . And after having the car running for a little bit I turned it off and when I turned the key my volts were aroung 9 and wouldnt start again. . . Sucks cause its an almost brand new xs batt I got from sonic a couple months ago

[Bayuk89]

You said your battery was dead and needed a jump... Your battery is prolly too dead to accept a charge and your car is running solely on the ALT, which is now under heavy strain and prolly cant keep up with the demand and that may be the reason your having this issue... Load test the battery and check your power and ground connection at the battery.

[frogcase2002]

You said your battery was dead and needed a jump... Your battery is prolly too dead to accept a charge and your car is running solely on the ALT, which is now under heavy strain and prolly cant keep up with the demand and that may be the reason your having this issue... Load test the battery and check your power and ground connection at the battery.

Yea kinda thinking its the battery. . The connections are really good and the batt is an xs and almost new but I guess it could just be a bad batt . . I just took a look at it and seems to be a little swollen on one of the top corners. Like a seam is braking

[tdsa23]

Sounds like the Alt or battery take them to an auto store to get tested.

[frogcase2002]

Yea I was kinda thinking alt and or battery. Just never had a car act like this is when batt or alt was bad

[Bayuk89]

^^^ could also be your ALT is internally shorting out and pulling juice from your battery causing it to drain ( had some of our machines at work do it )

[Jessica]

probably a bad voltage regulator in the alternator.