Mechanics - help needed (1 Viewer)

[bonnjer]

Here's the story:

2004 Jeep Grand Cherokee, bought it used about 2 1/2 years ago.

5/12/09 - original (as far as I can tell) battery died, replaced it with a Duralast from Autozone
July 2009 - original alternator (as far as I can tell) went out, replaced it
12-2-09 - Duralast battery that was put in May 12 died, had a bad cell, cold weather finished it off
12-22-09 - Duralast battery that was in Dec 2 died, pulled it, brought it to Autozone, swapped it out, working fine

Guy at Autozone said that since I had just replaced the battery, it might be the alternator. That's when I told him I had replaced that back in July. On the display panel, the battery gauge shows a steady 14 whenever the vehicle is in use. Any ideas on what this could be? Bad luck with getting bad batteries?

 

[BullDawg]

If you have a multimeter, put it across the battery terminals with the engine running. You should read 13.8 volts.

 

[mikaloyd]

Im guessing bad luck.

 

[soggymoss]

One very good possibility would be you might a wire shorting out somewhere. First places to check for that would be around the lights and other places where it would be easy for a wire to pinch.

 

[DadsDream]

Is there an under-hood or trunk light that is activated by a switch?

I went through two batteries before finding out that the ON/OFF light switch on my trunk latch was misaligned and the trunk light stayed on all the time. If I didn't drive for a couple of days, it was enough to drain the battery completely.

 

[parlorcitysaint]

You may have a flukey alternator. Many years ago, the regulator was a separate entity from the alternator. Nowadays they're in one unit. If the regulator part of your alternator isn't working properly, the alternator may be working properly in that it's producing juice, but working improperly in that it's not recharging your battery.

 

[Saint77]

Not to knock on Autozone's good name int he parts bisuness, but its entirely possible you got some back picks of the litter. I take it the belt is in good shape?

It may be hard to determine if you have a drain somewhere. Problem is, in most cars today, they all have a drain on the battery as normal. For instance. the radio, ECM, and various other computers like the one of the antilock brakes often need some juice.

What I used to do was disconnect the negative battery cable, and connect one end of a test light to the terminal, the other end to the the cable end, if it lit, you had a drain somewhere, if it didnt, then you dont.

 

[BHM]

Well, it sounds like your battery is not just being discharged by some random load remaining on. A light left on will not generally cause a bad cell.

It could be a missing heat shield around the battery. Excessive engine heat could be killing the battery. AutoZone should also be able to run a full check on the alternator. A faulty regulator could overcharge the battery and damage a cell.

 

[txhal9000]

So...did you figure it out yet?

 

[bonnjer]

Haven't figured out what the problem is. It seems as if there are a lot of different possibilities here. I will bring it by Autozone for a full check on the alternator.

I did check to see if all internal lights were going off after closing the doors. They all went off properly. My wife did have a cell phone charger plugged into one outlet and a VCR/TV combo for the kids plugged into another outlet, but the charger wasn't connected to a phone and the VCR/TV combo was off. I have those unplugged now. Could those being plugged in cause something like this?

 

[BullDawg]

Haven't figured out what the problem is. It seems as if there are a lot of different possibilities here. I will bring it by Autozone for a full check on the alternator.

I did check to see if all internal lights were going off after closing the doors. They all went off properly. My wife did have a cell phone charger plugged into one outlet and a VCR/TV combo for the kids plugged into another outlet, but the charger wasn't connected to a phone and the VCR/TV combo was off. I have those unplugged now. Could those being plugged in cause something like this?

It's doubtful it would have that much of a drain on the battery.

 

[bonnjer]

Didn't think so.

Right now, I'm leaning toward bad luck on batteries, with something up with the alternator/regulator as the backup explanation. Of course, I could be wrong and further thoughts would most definitely be appreciated.