I have an '04 Chevy Cavalier purchased from previous owner a few years ago. Have been through 3 or 4 new batteries already. It will be fine if driven daily (even if only a couple miles a day), but if it’s not driven for a day or two, the battery dies. At first, the lights in the car and everything will still come on, it just won’t start or will have difficulty starting. After that first time of being difficult to start or not starting though, it gets worse and worse. At first, I’ll be able to charge the battery and use it for a day or two without having it completely die on me, but it quickly gets to the point where you have to jump it to start it every time and loses the ability to hold a charge at all. Soon, the battery will completely go bad and you won’t even be able to jump it. It will be completely incapable of holding a charge. I’m not sure if it is an alternator problem or a problem somewhere in the electrical system.
Half the dashboard lights are very dim-not working; the overhead light occasionally has issues where it will flicker on and off when taking a turn, going over any kind of bump, or hitting the breaks; the trunk light used to sometimes work, sometimes not work until my ex’s grandfather decided to rip it out. Those are the only other things I know that are weird about it electrically. I’m hoping to be able to take it to a mechanic pretty soon, but would like to have an idea of what might be going on beforehand. Thanks.
Edit to add: Have not had it die while driving, just can’t start it again once shut off.
I can not physically see the vehicle, but I suspect that the first thing they will do is check the alternator, battery and all cables in between. Then do a parasitic drain test.
Does the car have a non factory radio? Remote starter? Car alarm? If it does, check those first for parasitic draw as @tcmichnorth suggests.
In less technical terms - something IN the car is not turning completely off and draining the battery. Sort of like if you left the lights or the radio on and never turn them off. Aftermarket products tend to be junk and will do this.
It has a radio from Wal-Mart that isn’t connected to the ignition or whatever, like you can turn the radio on without turning the car on and you have to remember to turn it off when you turn the car off because it won’t shut off itself. Was missing some wire to connect it and never got it put in. Can’t remember if I got the radio before or after the first time the battery thing happened, but it very well could be that maybe? I didn’t know that could be an issue.
It’s very rare that it does it and it comes on and shuts off correctly from opening and closing the door, so I’m not sure if that would be an issue or not, but it’s worth checking out. I was thinking maybe a bad wire or connection somewhere that causes it when the car bumps around too much.
Update: Girl at the mechanic’s said she knows that they’ve recently had some cars in where the radio was draining the battery, so I’m definitely going with @tcmichnorth suggestion of trying unhooking the radio first. Thanks everyone for your suggestions!