The trouble you are having @emilytris should be pretty simple to find. You need to take it to a good shop that has experienced techs on electrical systems for cars. Along with the normal tests used for this kind of problem the alternator needs to be checked for AC voltage output due to bad diodes inside the alternator. Excessive AC voltage can kill a battery.
Hereās the solution:
Iāve had this problem twice on two different Buick Rivieras and it is just by chance you can figure out what it is. On the one I had replaced the battery but still would intermittantly go dead. One night I went out to the garage and the interior lights were on. There was a short with the door handle that would turn the lights on when you pulled on the handle. The other one turned out to be the electronic load level sensor. Just went dead in the parking lot. Didnāt get any unusual loads with a test light and then all of a sudden it showed up. Disconnected it and no problems since.
If it happens every night though, it should be fairly constant and easy to find. Just have to start eliminating circuits until the right one is found. Iād pull half the fuses one night and the other half the next night to narrow it down, or just camp out in the garage for a few nights and see what happens.
A cheap test of the evap system is to open the gas cap and park the car. If you can start the car in the morning you know what to think next.
I think you need to bring in a specialist. 18 batteries in two years, who can afford that, or the aggravation? Take a look in your yellow pages, see if there is a listing for something like āauto-electric specialistā. A dealer shop probably isnāt qualified for this. You need someone who has an electronic tool that can monitor the current in the battery cable automatically and log it to memory overnight. Then review the log file the next day for anything unusual. There pretty much has to be a time during the night when a big surge of current is occurring. The computer is probably doing something it shouldnāt be. But this has to be caught first, so you have proof, otherwise mechanics will just throw up their hands.
One way to prove what I said must be happening is to disconnect the negative battery cable every night. If the battery remains fully charged the next morning, and you can put the battery cable back on, and everything works fine, that pretty much clinches it.
If you were the scientific type, since current in a wire causes a magnetic field, you could probably rig up something like a paperclip balanced on a perch of some kind, that would prove there must be a current occurring during the night, b/c the next morning the paperclip has toppled from its perch.
Iād like to know how in the world any battery is replaced 18 times under warranty because after a couple of events someone at the top of the corporate warranty chain is going to apply the brakes and say no more.
did you ever find the problem ? i have same problem with mine. can it be the evap cousing battery drain over night?
Unfortunately, I did not. 3 years ago I bought a knife switch top for the battery, and manually disconnect/reconnect the battery every time I start or stop the car. Itās pretty hacky, but Iāve yet to find a mechanic who can diagnose what exactly is causing the drain (despite having been to half a dozen across three states since my original post!!).
If I remember to disconnect the battery, I never have any problems. It can go a night or two fully connected, but itāll die after three days of being connected, guaranteed.
I know this old but just what will this prove or disprove?
Most mechanics are able to diagnose the source of phantom battery drain. But it has to be happening while the mechanic is looking for it. The problem might be that the drain occurs in the middle of the night when the mechanic isnāt there. There are instruments available that can monitor current usage and report when the high current usage times occur, or even set an audio alarm. But I doubt those instruments are commonly used at most auto repair shops.
I expect thereās quite a few cars out there that wonāt be able to sit unused for 72 hours and still crank the engine reliably, especially in cold weather. A problem with the starter circuit could be the actual culprit, and then if the battery is even slightly discharged it wonāt be able to crank the engine.
For the umpteen time I have had two battery drain problems. One on each of my Rivieras. I found the one by happening to go out in the garage at night and the interior lights were on. It was a problem with a short in the door handle that activated the interior lights when the handle is pulled. I just disconnected it and no more problem but it was very intermittent. The other one was a problem with the device that senses the rear leveler. Almost gave up and then all of a sudden the test light got bright. Disconnected that too.
Normal ones are trunk lights, glove box lights, etc. that donāt shut off or come on once in a while. Normal way is to hook the test light up and pull fuses till the light dims and then trace that circuit. But if it only happens sporadically, you have to be there. Maybe a game camera to see what comes on at night. Just have to stay at it.
Years ago my dadās car had a parasitic drain killing the battery. Turned out the previous owner had a hookup for towing and the wiring to run brake lights on a trailer were somehow draining the battery. The wires had been tucked up out of sight underneath the rear bumper so mechanics didnāt spot them for a long time.
my 2010 Aveo would be dead if it sat over weekend, took it in after $300 they told me my battery drain was caused by bad radio, try pulling the large yellow fuse see if that stops your problem, i have ordered a radio to replace mine . machanic claims radio has a short in it causing the drain, so will see
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Mine couldnāt. The security system would drain the battery in three days. Is an animal causing the security system to activate? Once a car of mine would drain the battery. The mechanic put in a new door switch to the overhead light. The light seemed to work OK, but the rusty switch drained the battery.
Aftermarket security system?
Yes, my aftermarket security system would drain my battery in three days. Made the car hard to start in the winter.
Personally, Iām not a fan of aftermarket security systems. In my experience, the problems they introduce outweigh any benefits. Iāve removed a few, because the alarm would sound often, for no good reason, problems starting because the system incorrectly sees an āunauthorized startā, battery drain, etc. And in every case, removing the system and bringing the car back to stock resolved the issues
It may be that version of security system has a larger off-state current drain than most. In which case youāll just have to live with it by remembering to drive the car at least every other day, or remove the security system. From the posts we hear here, some cars ā these tend to be upscale specialty cars like high end sports cars for the most part ā new from the factory will drain the battery in a week or less if they arenāt driven. Itās all the gadgets and gizmos these new cars have now that does it.
As far as phantom current drains, the most common reason we seem to hear is a faulty door, trunk, or hood switch. After that, thereās a light thatās staying on, usually the trunk or the glove compartment. And security systems are a pretty common reason for phantom current drains too.
I donāt seem to recall this discussion . . . ?
I cant believe we would agree that what you described about the high end cars is a normal and acceptable condition
The one I remember discussing here was the Porsche Boxster. Google āBoxster battery drain problemsā for examples.