Bad Charging System or Crappy Batteries?

[Twister]

I have had a problem with keeping batteries in both my Bronco II's, i bought a walmart battery about 3 years ago because my brother has had excellent luck with them, i wish i could say the same. I have had to get them replaced under warranty about every 7-8 months. I just got it replaced about a month ago and this one is already dead . Could this be just crappy walmart batteries or is there something seriously wrong with both my truck, and if so, how can I find out what is wrong?

I dont think they will replace it a second time when i am out of the warranty period.

 

[adsm08]

Test AC and DC voltage, at the battery, with the engine running, all accessories on.

 

[shane96ranger]

It could very well be a weak alternator. Get it bench tested. I've had the POS that Autozone brings out to your car tell me my alternator on my Escape was bad. I put a new battery in it (warranty), and oliver sudden it tests good now.

The alternator is a PITA to pull, so I didn't bench test it.

 

[Twister]

Well recently it has started making this horrible squealing noise every once an awhile, i haven't driven it much because of that. Wonder if that could be the alt.

 

[shane96ranger]

Well recently it has started making this horrible squealing noise every once an awhile, i haven't driven it much because of that. Wonder if that could be the alt.

Or the belt?

 

[Twister]

Well after it sat over night, the battery dropped to 3.5v.

So after jumping it, running with no acc on it read 13.9v DC and .02 AC, with acc on it read 12.9v DC and .02v AC. After turning it off it dropped to 12.2v and would steadily drop.

I am going to take the battery and the alt in to get them tested on Friday.

 

[adsm08]

Alternator is bad, regulator/rectifier are working properly. A bench test will probably tell you the alternator is ok because most of those machines only look for 12 V. You should ideally have at least 14 with accessories on.