What is up with my car?

July 25, 2010 6:49 PM

What's wrong with my car, and what's my best option for fixing it?

I'm having some recurring battery issues. I took a long trip out of the country this summer, and my car was parked in the garage for the duration of my trip. When I got back a week ago, the car wouldn't start. AAA gave me a jump, and sent me to a garage they have some deal with in my area. The garage told me that I needed a new battery, and installed the new one. The car was then fine running errands around town for the next two days. Then it was parked in the garage again, unused, for two or three days... and now the car won't start again.

Two questions:
(1) What could be wrong with my car, seeing as I have a brand-new battery and it now won't start again? (I know YANMMechanic and it's probably hard to diagnose without seeing the car.) I definitely didn't leave any lights on at any point.
(2) What's my best option for dealing with this? The battery was installed at this garage, but through a AAA deal - I think the warranty is from AAA. Should I call the AAA line again, or just directly call the garage they sent me to for the first battery? I need to talk to the garage at some point in the process to get anything fixed, but I'm wondering if I need to go through AAA for warranty purposes.

Additional possibly useful information:

-My car is a 2006 Honda Civic.

-I'd been having (probably) battery-related issues for a few months before leaving. I needed a jump back in March with no provocation I could think of (hadn't left lights on or anything). It was fine for some time after that, but by the time I left the country in June, the key fob was getting slow to unlock the car - it took a few clicks before it registered.

-I live in the northeast, where there have recently been a couple unpleasant heat waves. I don't know if the heat would have anything to do with the car troubles, but I thought I'd mention it.

posted by pemberkins to travel & transportation (15 answers total)

IASaHNAM (I Am Sure As Hell Not a Mechanic), but whenever similar things have happened to me, the alternator has been at fault. Check this brief article for more info.
posted by julthumbscrew at 6:59 PM on July 25, 2010 [2 favorites]

Perhaps, a dying alternator so the battery isn't being charged fully.
posted by rancidchickn at 7:00 PM on July 25, 2010 [2 favorites]

One possibility it that there is some unnoticed device that is draining power from the battery when the car is parked. An example would be a light in the trunk that is stuck on when it shouldn't be.

Take it back to the shop and ask them to check for a battery drain. They will put a current meter on the battery to see if there is leakage and then pull fuses to determine where the leakage is occurring.
posted by JackFlash at 7:02 PM on July 25, 2010

Same thing happened to my last car, a 2002 BMW M3. A bad starter was eating batteries. Changed the starter, worked fine (until I wrecked it... RIP)
posted by milinar at 7:04 PM on July 25, 2010

It definitely could be a dying alternator that isn't fully charging the battery. That said, the fact that the problem doesn't manifest itself until the car has been sitting for an extended period of time, makes me wonder if you don't have some sort of trickle discharge that is draining the battery over a few days. Do you have any sort of third-party equipment on the car? Like an amp or an aftermarket alarm?
posted by Thorzdad at 7:06 PM on July 25, 2010 [1 favorite]

Usually if you have a bad alternator, the car will fail to start after short trips. A battery will exert a certain amount of energy to start the car and a good alternator can replenish a good battery within about 10 minutes of driving. After ten minutes, a good battery should constitute a load on the alternator of under 10 amps, which is not much. What's most likely, given your description, is that something is remaining on or some circuit is continuing to draw power when the car is switched off.

So, you're going to have to take your car to a mechanic and have them check for a parasitic draw, in addition to double checking the charging system, just to be safe. You should also make sure that you get a decent name brand battery installed in your car because, in my experience, AAA batteries are junk.
posted by Jon-o at 7:30 PM on July 25, 2010 [2 favorites]

When it fails do accessories like power windows, lights, fans, or radios still work or is everything electrical dead?
posted by Rhomboid at 7:33 PM on July 25, 2010

Checking alternator output is obnoxiously easy. Don't dawdle on checking it; alternators can fail such that they output way too MUCH power and cook a battery. If that has happened, however, this garage should do the right thing and eat the cost of the battery. There is no justification for not checking the alt when replacig the battery.

If that's not the issue I second the concern about a trickle discharge. I can't remember it ever happening to me on a battery that wasn't on it's way out already but I can say with confidence that there are devices that will suck down the juice. Does your cig lighter plug stay live whe the car is off? Do you have an after-market car alarm or cd changer/iPod hookup installed?
posted by phearlez at 7:45 PM on July 25, 2010

I have a 2004 Civic, and recently had to replace my battery and alternator. But my first indication that something was wrong was that the battery light on the dash came on. Owner's manual says when the battery light is on, it means that the battery isn't charging. So if yours isn't on, you may have a different problem.
posted by MexicanYenta at 8:08 PM on July 25, 2010

Nthing checking the alternator is charging properly (should have been checked by the shop when they installed the new battery), and whether something is draining the battery when the ignition is supposed to be 'off'.

Have you installed a new alarm, or any other accessory in recent times?

It is possible that a bad starter motor will stuff up a good battery, but your symptoms don't point to that, but get them to check that too when the others are being looked at.
posted by GeeEmm at 8:17 PM on July 25, 2010

My old car had a string of similar electrical problems. Replaced the battery, swapped the alternator with a refurbished one, and was about to spring for a new one when the shop checked the wiring harness running under the engine. There were some shorted wires in there that turned out to be causing all the problems. They weren't found before because the shorts would only occur once the wires touched, and for some reason this would only happen when the engine heated up. Something to think about if the alternator checks out OK.
posted by Hardcore Poser at 9:07 PM on July 25, 2010

I don't have any 3rd party equipment installed in the car. I do own a GPS but I only plug it in when I'm using it; it lives in the glove compartment otherwise. No alarm, CD changer, iGadgets, etc.
posted by pemberkins at 9:38 PM on July 25, 2010

I do own a GPS but I only plug it in when I'm using it; it lives in the glove compartment otherwise.

Do you leave the power adapter plugged-in to the car, though? I've seen cases where those things actually can drain a battery if left plugged-in. The cheaper ones lack the simple circuitry that halts the power flow if not connected to the GPS/phone/ipod/etc. while also sporting a light that stays on all the time.
posted by Thorzdad at 3:42 AM on July 26, 2010

No, I put the adapter away too.
posted by pemberkins at 7:51 AM on July 26, 2010

Hmm.. There could be a short somewhere in your car's electrical system that's draining the battery. I know finding a short can be incredibly difficult. Are all the electronic components in your car working - power windows, power locks, power seats, heated seats, alarm etc?
posted by parakeetdog at 1:29 PM on July 26, 2010