Battery not charging--open circuit?

[CarFreakGT]

Hi, guys--thanks in advance for any input that you have. Sorry so long. Here's what's going on:

My battery is not keeping a charge--dying after a couple trips out in the car. The battery is new and has been checked--it's good. Alternator has been tested off of the car--it's good. New belt has been put on for good measure--old one was 4 years old and in good shape. Everything is grounded and connected.

I'm getting ready to go double-check that all connections are good and clean, and I'm going to take the alt. and battery to have them checked again, just to make sure all is well.

Anything else that anyone can recommend checking? Could I have an open circuit somewhere that's constantly draining my battery? If so, what's the best way to go about checking/finding it?

Thanks again--Bryan

 

[blackcloud50]

what year car and have you taken voltage readings with multimeter?

 

[kr8zstang]

When you start your car, does the battery dash light come on? If not, thats your problem. I had the same problem a few months ago and it took me forever to figure that out. When the light comes on, it tells the alt. to start charging. If it doesn't come on, you will get nothing from the alt., even if it's fine. Hope this helps.

 

[TheUser]

I'm with these guys: Take a voltage reading from the battery with the car running - watch it for a few minutes and see if it decreases. It should be 14+ volts or so at the battery with the car running.

If it is decreasing, I would suggest checking out the wire that goes to from the starter solonoid to the alternator...the fusible link that connects to the starter solonoid could also be bad, so see if it's melted or anything (it's the green 14ga wire connected to the starter solonoid - same side as battery pos. cable).

 

[CarFreakGT]

Thanks, guys! I'm off work today and under the hood. I will check these things out.

By the way, since I forgot to mention: it's an 89 GT, 5 spd., stock except exhaust.

 

[88GT17MA]

Check all your small interior lights, make sure one isnt stuck on.....even the small bulb in your glovebox could be draining the battery when the car is not on.

 

[CarFreakGT]

One more question. When the alt. is checked, it also checks the voltage regulator, right? I assume that it does, since the voltage regulator is on the alt.

 

[bobbyd]

I have teh same problem same scenario as you. Im also gonna check this out today as soon as my battery finishes charging

 

[CarFreakGT]

bobbyd--let me know if you figure anything out. My alt. and battery checked out fine. All wires look good. I bought a multimeter this evening, and I'll check my battery w/ the car running when I put it (the battery) back in tomorrow or Thurs. If it's draining, I'll check the things that were mentioned by others above. If anyone has other ideas, please let me know.

Thanks, everyone.

 

[bobbyd]

bobbyd--let me know if you figure anything out. My alt. and battery checked out fine. All wires look good. I bought a multimeter this evening, and I'll check my battery w/ the car running when I put it (the battery) back in tomorrow or Thurs. If it's draining, I'll check the things that were mentioned by others above. If anyone has other ideas, please let me know.

Thanks, everyone.

Will do. I didnt get to do it yesterday but i'll do it today and if i figure out the problem ill let you know and if you figure it out before me let me know thanks

 

[CarFreakGT]

By the way, what should the voltage be cold? Sorry if this is a stupid question, but I'm electrically-challenged.

 

[blackcloud50]

By the way, what should the voltage be cold? Sorry if this is a stupid question, but I'm electrically-challenged.

Really depends on the state of charge your battery is in to begin with and outside temperature. But in general, around 12.5 - 12.6 V

 

[blackcloud50]

this may help you...Scroll down the page see what I have referenced in above post.

http://www.uuhome.de/william.darden//carfaq4.htm

 

[bobbyd]

well last night i disconnected the wire that goes from my battery to the capacitor to see if that was my problem ill try to start the car later today.

 

[jrichker]

Troubleshooting battery drains...

Typically it is something draining the battery. Small things like glove box or courtesy lights are often the culprits. If you have an aftermarket stereo or alarm system, it is also suspect.

The ideal method is to disconnect the positive terminal, and connect a Digital Multimeter (DVM) between the positive terminal on the battery and the positive cable. Set the DVM on a low current scale of 2-5 amps if it doesn't auto range. Watch the current draw, and then start pulling out fuses. When you see a sudden drop in the current, that circuit is the likely culprit. Note that the computer, radio & clock will draw less than 1/10 amp to keep the settings alive.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf. You will need the Adobe Acrobat viewer which is also a free download – http://www.adobe.com/products/acrobat/readstep2.html

 

[CarFreakGT]

Oh my gosh--could it be this easy and could I be so lucky?!!? Jrichker, you reply may be perfectly timed as well as correct. I just logged on to say that my passenger side sunvisor vanity mirror may be the culprit. At times, I have noticed that the velcro is showing its age and not holding the flap that covers the mirror closed very tightly. Of course, this same flap in turn holds the button down that turns off the lights by the mirror when you close the flap. I have a very 'high-tech' electrical tape rigging holding the button down to keep the lights next to the mirror from staying on.

Right now the car has been running ~5 minutes and the battery is consistently holding 14.6-14.7 V at idle. I'll let it idle 5-10 more minutes and see how it does.

PLEASE let this be the answer . . . it has been driving me nuts for weeks now! Thanks!

 

[bobbyd]

When you start your car, does the battery dash light come on? If not, thats your problem. I had the same problem a few months ago and it took me forever to figure that out. When the light comes on, it tells the alt. to start charging. If it doesn't come on, you will get nothing from the alt., even if it's fine. Hope this helps.

mine comes on when i turn the key but as soon as I turn on the car it dissapears.....does the light have to be on when the car is running?

 

[Saleen0679]

No. The Charge indicator illuminates briefly at startup and should not come back on unless you have a charging problem.

 

[bobbyd]

No. The Charge indicator illuminates briefly at startup and should not come back on unless you have a charging problem.

coo thankx then hopefully i have fixed my problem by changing the cables on teh battery