Need battery/charging help

[brazzle]

Hi all,

I know very little about cars compared to you guys, so I have come to you for help. Let me give you some background info:

About two months ago, it seems like out of nowhere my 2002 Explorer V6 4.0L wouldn't start. There was enough power to run the headlights and all internal lights, but when trying to start it all I would get was a very rapid flickering until I released the key. After cleaning the rather corroded contacts and charging for 10 minutes it ran fine. We checked the charging meter and it was right in the middle and I never noticed it drop at all, so we assumed it wasn't the alternator.

Well, two days ago while getting my oil changed, the technicians ran into the same problem and had to jump and charge it. They noted on their sheet that they believed I had a bad battery.

Today (two days later), I tried to start it after not having driven it since the oil change and I had the same rapid flickering. I assumed I needed to get a new battery so I jumped it and took it over to Autozone. The guy pulled out his machine and set forth on testing the battery while my Ex was off. He said it fell from 12V to 8V and that he believed I had a bad cell in the battery; however, the machine read "Charge and Re-Test" so he had me start it up while he tested it some more. After asking me to hold the RPMs at 2K there appeared to be a bit of flickering and I caught a glimpse of my charging meter rise from Medium-Low to Medium. I wondered if that could be a result of the machine since I had never had such a thing occur before. After that he told me the battery was fine but it seemed like my alternator was bad.

Ouch. Thats not good for someone like me who can't change it himself.

My question is, except for that one fleeting moment, I have never noticed my charge be low at all and while driving home I ran a system check and it said the charging system was "OK". Is it possible the Autozone guy/machine were wrong and it really is a bad battery like he originally supposed?

I really don't want to have to replace my alternator, but above all I don't want to waste money on something I don't need.

 

[crash594]

1) if the battery drops from 12 to 8 volts it is toast. I would replace the battery and drive it for a couple of days and have it re checked. I bet the ALT passes

2)Your amp meter moving is from the test

 

[DirtyDog]

Once your battery goes dead (two months ago) you need to fully recharge it with a charger because no matter how good your alternator is, it will never fully recharge the battery.

Do you have any accessories that you leave plugged into power points like a sat radio or phone charger? These kinds of things can slowly drain your battery

 

[brazzle]

thanks for your help guys.

DirtyDog,

I try to never leave anything plugged in, but sometimes mistakes happen. I think the oil guys actually left the lights switched on because they were went I tried to start it yesterday.

So you guys think its pretty safe to say this is simply a bad battery? Any good ways to check and rule the alternator out?

EDIT: As a side note, the Ex started fine this morning.

 

[brazzle]

Hey all, just to revise my question a bit:

Is the amp gauge in the Explorer accurate? Can I assume that if it is riding in the middle that my Alternator is providing a good charge and that the battery is bad?

Sorry if I'm being pushy, I need this vehicle (and I love it) and would like to go and get the battery replaced today if it seems like a battery problem.

EDIT: kind of sounds like i'm ignoring the input above, actually I'm just trying to find out if it is possible that both the battery and alternator could be bad or if there is any way a bad alternator could cause these symptoms (like the voltage drop from 12 to 8)

Thanks,

Braden

 

[jrford]

I have a '04 what you are describing sounds like a bad/dead Battery.

About 2 years ago my then 3yr old daughter really liked to watch a movie while camping, so 2 hours of running the radio, the truck wouldn’t start in the morning, twice. So I took it the Battery to Autozone they tested it OK too, but I knew it wouldn’t hold overnight so I bought one (Gold) anyways. Well two years have gone by and many movies but the truck always starts, never a problem. I would do the Battery First and you should be all set.

However, many years ago, when gas was about $1 and my car was an AMC it wasn’t uncommon that if you fried your Battery the Alternator would go soon after as they are dependant of each other, the opposite is true if the Alternator is failing your battery would die soon also.

 

[jrford]

And you might want to get it fixed sooner than later, some guys had problems when their battery went completly dead. The truck would not start at all, flashing security light, as the PCM forgot what keys where programmed with the dead battery. They had to have it towed to the stealership to reprogram the keys.

 

[brazzle]

jrford,

thanks for your input. its a relief to hear from many others that it sounds like just a bad battery. i picked up a gold from Autozone this afternoon and will install it tonight when I have access to my wire brush.