Folks... I was wondering if you can help me out with this. My car has been in the garage since the start of winter (avg. temps ~23 F). I have been starting it for about a 1/2 hour every month, and moving it around the driveway and garage and such. The last time, after I shut her down, I stupidly engaged the anti-theft system. The next month that I tried to start her, the lights and everything were barely coming on, and obviously it wouldn't crank. So I jumped her, and all was fine... let her run for 1/2 hour again, then shut her off. The next month, she was totally dead. I figured I didn't let her recharge all the way from letting her idle.

So I bought a battery charger, let her charge... she started up fine. Darn thing is, I can't quite remember if I let it 100% completely recharge... but anyways, she started fine. This month (last night), she was dead again. So I let her charge fully this time... over 8 hrs... I didn't start her yet.

So my question is, is it the battery? (I hope)... or is it the alternator? The battery is 3 yrs old, so maybe it can't take a charge anymore. I hope it isn't the alternator. Does an alternator charge up the battery in idle? Am I just not giving it enough time (1/2 hour at idle) to charge up? How exactly does that work? Another thing, could there be a short somewhere that is draining the battery? I doubt it... I've been driving it like that for forever, and it was always fine in summers...

Thanks for your help.

 

Modern (no or low maintenance) batteries are often killed if they are completely drained, especially if they sit for a while discharged. I'd suspect that first, especially since it wouldn't hold a charge.

 

Do you have a PFC or a volt meter? If it shows 10v fully charged or imediately after you turn the key then the battery has a bad cell and needs to be replaced. If the voltage drops while cranking but returns when you let the key go, then a bad ground connection. If it shows 12v after cranking then you should have the alternator tested. If you can remove it and take it to a auto parts place they should be able to test it for free. If you can jump the car and it stay on then most likely it's the battery cause it would die if it was the alternator.

 

Just start the car and disconnect the battery if the car runs the battery is toast, if it dies get a new alternator.


EDIT* I am erasing my commas.

 

Yep.. That's true! Damn, that reminds me.. I need to start one of my car.. its been sitting since last year..

 

what kinda battery charger did you get? if you got a trickle charger, its nto gonna beable to bring back a dead battery



it should take about 2-3 hours at about 15-30 amps of charging just to charge a good battery correctly. it is true that our alternators do put out 100amps but remember, thats at 3000rpm and its not like you can really juice the battery in to accepting all that ampage. in anycase, id bet its your battery. BTW: you might wanna check your ghost amp draw just in case

lastly, did you test the specific gravity of all the cells of your battery? that and doing the test iluvmy3rdgen mentioned and getting a multimeter and testing the voltage to your battery should tell you what it is fairly quickly. the only thing i would change about this statement "Just start the car and disconnect the battery if the car runs the battery is toast, if it dies get a new alternator." is to disconnect only the negative side of the battery. dont touch the pos side when the car is running and be very carefull when handling it at all or your gonna do some welding, perhaps with a peice of your body...

 

Id probably say its your battery too. I had the same trouble with my car and bought a new battery...starts every time. Once the battery discharges, you know its time for a new one. Optimas are really good and dont discharge as easily as the regular sears or autozone standard batteries. just my .02 cents

 

thanks guys... I sure hope it's the battery too. I have to wait another month before I get her out on the road though The salt on the road will kill her...

Skunks: I bought a charger with maintenance/trickle charge, and one with a straight 6 amp charge. I charged her up last night, and it took the charge. Either way, I might still end up buying a battery this spring.

Goracer: sorry, I don't have a PFC or voltmeter. My mods are dp and catback...

ilumvmy3rdgen: my car keeps running for however long i start it. So i guess that means it's not the alternator???

 

Correct