Need help quick! Battery won't charge!

[sumenlo]

So coming home from the bars the other night, my headlights, interior lights, and all my accessories start to go really dim like my car is having trouble charging the battery. Obviously, my first guess is that the alternator is going bad and needs replacing. So after barely making it home that night, I replace the alternator the next day. We push start the car, and I let it run for about 10 minutes to get the battery nice and charged. Everything seemed fine up to this point. Well this morning, on my way to work, my car won't start. I get a guy to help me push start it again, and everything is fine. Until I get to work that is. As I'm pulling into work, my car starts idling really low and my stereo goes off. Same thing that happened the first time around. I'm confused here. Brand new alternator, battery should be fine. Even if the battery isn't holding a charge, shouldn't the alternator keep power to the car while it's running? I need some help here guys. My car is stuck here at work and I gotta leave in 8 hours. Thanks.

 

[weith1111]

You can't successfully charge a dead battery off an alternator with the car idleing for 10 minutes. In addition you can destroy a new alternator putting it on with a dead battery. Get the battery tested and charged to full, or get a new battery.

 

[sumenlo]

I don't really understand how you can destroy an alternator if you connect it to a dead battery. Doesn't the alternator act as a battery charger? Plus, my battery had just enough juice to provide spark to push start my car. So it wasn't completely dead. Just not powerful enough to turn the starter.

 

[jasoncitrano]

Same thing happened to me thought i was going crazy. Check your voltage while the car is running.

If it's under about 13.8 volts alt problem

If it's at 13.8 or higher volts look into the battery.

My alternator fuse was blown, i think it's an 20amp block fuse under the hood. You could have been just running your car on the battery...i think that becuase the radio shut off.

Recap: check to make sure the alternator is actually charging the battery. Check the alternator fuses and the battery terminals are clean and tight. Make sure no oil gets into the alternator either cuz oil kill's em.

 

[weith1111]

Most likely the alternator is fine, but it is not designed to charge a battery from dead to full.
I'm not going to go into great detail about alternators, but their use is to replace the power the electrical system is using. If you want to charge a battery, get a battery charger!

Batteries are a little more complicated than just alive or dead. It may not hold a charge, it may be damaged, it may never accept a full charge again. The easiest and cheapest way would be to take it to Autozone and have them check it out, and they will charge it for free if it is fine! Chances are, if your battery is a few years old, and had to put up with a dying alternator the last 6 months, it isn't doing so hot.

 

[c5chris]

Disconnect the battery and take it to Pep Boys or Autozone. They will check the battery and for a minimal amount of $, recharge it.

You can drain a battery to a point that it will no longer hold a charge. Some chargers can revive it by feeding it a minimum amount of current and slowly building it up to full charging capacity.

 

[sumenlo]

sounds like i have some things I can try. I'm probably just gonna replace the battery anyway just to be safe. I'm not sure exactly how old it is but chances are it's over a year. (I've only had the car for about 5 or 6 months and the battery wasn't new when I got it.) I'm thinking that the fuse could be the problem. I currently have the fog light mod done to my car and have a jumper wire running off of that block fuse. It's been giving me problems the last week and I've been messing with it so maybe I shorted out the fuse. Sounds like I have some different things I can try anyways. I'll keep everyone updated.

 

[sumenlo]

okay, so i just replaced the battery (thank god for wal-mart). Hopefully that will do it. If not, it should be enough juice to at least get me back to my place so I don't have to leave the car in the mall parking lot. I also pulled the alternator relay block fuse to check it. How do you know if it's blown or not? does the black plastic cover come off of the rest of the fuse? I don't want to really mess with it and accidentally break it. From the looks of it, it's something that I would have to get at the dealer.

 

[Defiant]

Bolt the battery down and put a vinyl cover over the positive terminal so it can't short against the hood or strut bar again.

 

[sumenlo]

That's a good idea, thanks Defiant. But, does anybody know how to test that alternator relay? I want to make sure that is the problem before I spring for the dealership (you know how we all love that). There's no way to visually inspect it from what I can see. There is like a black plastic cover over it. It looks like it might come off, but I don't want to start prying at things and regret it later.

 

[talonTSIDriver]

I am putting my money on a battery. I had a simular problem on my 95 talon and I bought a new battery for $40 (after core deposit) and all was good.

Do what everyone else says, take it to autozone/advanced auto/pepboy and let them test it for free. Otherwise just buy a new battery, $40 is nothing these days.

 

[sumenlo]

replaced the battery last night, then tested it with a volt meter. The alternator isn't sending any power to the battery. Sicne the alternator and battery are both brand new, my guess is the relay now.

 

[akdsmer]

replaced the battery last night, then tested it with a volt meter. The alternator isn't sending any power to the battery. Sicne the alternator and battery are both brand new, my guess is the relay now.

You don't need to guess. Just check the two prong connector to your alternator with your multimeter. Both of these should have power with key on. One runs from the ignition switch (thus key needs to be on) The alternator relay is wired into this circuit. The other comes from a fuse-link (I don't remover which fusible link). If you don't have power at both of these, you are not going to have functioning alternator. Start there.

 

[boostedfwdtsi]

its prolly grounding out on your hood mine did about 5 times then the termanel welded it self to my hood and snaped off when i opened it grrr so know its coverd in carboard and duckt tape till i get one of them vw battery wraps of a jetta so make shure you cheack to make shure its not touching your hood your symptoms are what happend to me to good luck