bad battery? bad alternator? both?

Shortcut

Golden Member
Jul 24, 2003
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hope you guys can help me out:

about two months ago, i installed a new battery in my car.

recently, i left my car unused for a week. when i tried starting it a few days ago, i noticed there was no electricity available in the car (couldn't use powerlocks, cabin lights wouldn't turn on, dash lights wouldn't turn on, no radio, nothing!).

anyways, i jumpstarted the car, and everything seemed to work fine afterwards. i went out for a drive to make sure everything was ok. everything _seemed_ ok.

i left the car in the garage again until today. again, the car seemed to have no electricity (couldn't use powerlocks, no lights, yada yada yada).

i'm thinking either the battery and/or the alternator is at fault. any advice on how to easily identify the culprit?
 

BobDaMenkey

Diamond Member
Jan 27, 2005
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Batteries should last longer than that, even if the alternator is bad. You have a bad ground somewhere that's sucking out juice from the battery when the car is off.
 

Shortcut

Golden Member
Jul 24, 2003
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Originally posted by: cavemanmoron
take battery,and car, to Advance Auto Parts
ask them to Please test them.

:)

;) haha - that's a fine idea. i was hoping to save myself some cheddar. but i will definitely keep this in mind.
 

Shortcut

Golden Member
Jul 24, 2003
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Originally posted by: oldsmoboat
Why did it ned a new battery?

the old one was going on its sixth year of service, and the little round window on the battery said it was running low on juice.
 

SaturnX

Diamond Member
Jul 16, 2000
3,415
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76
I had a similar issue, where I'd leave the car for a night, and the battery would be dead. Turned out to be a faulty Day-Time Running Light module that I had replaced earlier was shorting and draining my battery.

Also, if you're driving and the battery meter is going up and not dropping down, especially with things like the radio and such on, then your alternator's fine, and your battery is probably fine.

Like mentioned above, you probably have a power drain somewhere.

--Mark
 

classy

Lifer
Oct 12, 1999
15,219
1
81
Start the car. Get a standard volt meter. While the car is running test the voltage across the battery. You should see at least 13 volts and most newer cars have 14 volts across. If you see that, then your alternator is working fine. If you see around 12 or less your alternator is bad or not functioning properly.
 

compudog

Diamond Member
Apr 25, 2001
5,782
0
71
Originally posted by: classy
Start the car. Get a standard volt meter. While the car is running test the voltage across the battery. You should see at least 13 volts and most newer cars have 14 volts across. If you see that, then your alternator is working fine. If you see around 12 or less your alternator is bad or not functioning properly.



Exactly. Or take it to Advance/Auto Zone/Local garage and have it tested. Sounds like a bad alternator to me.
 

cavemanmoron

Lifer
Mar 13, 2001
13,664
28
91
Originally posted by: Shortcut
Originally posted by: cavemanmoron
take battery,and car, to Advance Auto Parts
ask them to Please test them.

:)

;) haha - that's a fine idea. i was hoping to save myself some cheddar. but i will definitely keep this in mind.

if by cheddar you mean money,
the local Auto Zone/Advance Auto parts stores test batteries and ALternators for FREE.

;)
 

Shortcut

Golden Member
Jul 24, 2003
1,107
0
0
Originally posted by: cavemanmoron
Originally posted by: Shortcut
Originally posted by: cavemanmoron
take battery,and car, to Advance Auto Parts
ask them to Please test them.

:)

;) haha - that's a fine idea. i was hoping to save myself some cheddar. but i will definitely keep this in mind.

if by cheddar you mean money,
the local Auto Zone/Advance Auto parts stores test batteries and ALternators for FREE.

;)

!!!
:)
 

cavemanmoron

Lifer
Mar 13, 2001
13,664
28
91
Originally posted by: Shortcut
Originally posted by: cavemanmoron
Originally posted by: Shortcut
Originally posted by: cavemanmoron
take battery,and car, to Advance Auto Parts
ask them to Please test them.

:)

;) haha - that's a fine idea. i was hoping to save myself some cheddar. but i will definitely keep this in mind.

if by cheddar you mean money,
the local Auto Zone/Advance Auto parts stores test batteries and ALternators for FREE.

;)

!!!
:)

 

mandala

Senior member
Dec 24, 2003
210
0
0
If you only took it for a quick drive after jumping it, even if your alternator is working properly it wouldnt have been able to fully recharge your battery (especially if it was totally drained). If you have a small short and leave it sitting for a long time, it would be enough to fully drain the battery. If it's a big short, it'll drain it really quick. Check the voltage across the poles, or if you don't feel like doing that, take the battery in and have it checked.

I had a similar thing happen earlier this week. Went to start up my truck Monday morning and I had power but the starter wasn't doing anything. But whatever it did do (switch throwing the solenoid got stuck or something) was enough to drain my battery in a manner of minutes. After smacking the starter, and recharging the battery, viola! it worked. I think it was bad karma.
 

Soccerman06

Diamond Member
Jul 29, 2004
5,830
5
81
Your problem could also be bad wiring to a light or something that will draw power for an extended period of time. Check both ends of the terminals on the batery to see if its corroded, also check the other end of the cables and make sure they are properly hooked up and making full contact.

If it was your alternator, your car would run out of power on the road. It could be a bad battery but I doubt it. Also, check the belt on the alternator to make sure that it is making proper contact.
 

conehead433

Diamond Member
Dec 4, 2002
5,569
901
126
As others have mentioned first clean the battery terminals. Get the car running with jumper cables and use a voltage meter on the battery to see if your alternator is working. You should get 13.5 to 14.5 volts with the car running if the alternator is putting out OK. If the alternator is charging OK then put the battery on a trickle charger to get it charged up good. After charging it take it back where you bought it and have them do a load test on the battery. If it fails they should replace it although it may be prorated; it shouldn't be with just 2 months of use though. If the battery checks OK and your alternator was charging then you'll need to find whatever is draining the battery when you're not using the car. If you can't locate the problem and don't want to take it to a mechanic you could always just disconnect the battery ground cable when not using the car. Hope this helps. That'll be $100. LOL
 

LuckyTaxi

Diamond Member
Dec 24, 2000
6,044
23
81
It's the battery. I had my battery changed a few months ago. I then went away for the weekend and my car didnt move for 2 whole days. I went to start it up and it wouldnt crank. I got a jump and took it to R&S Strauss. They said the battery had a bad cell. I got a new one and all is well.
 

CRXican

Diamond Member
Jun 9, 2004
9,062
1
0
Originally posted by: Kalvin00
Just hope you didn't kill that battery by letting it run dead..

the battery will need to be replaced along with the alternator