To start off with I am a newbie to the forum and to doing my own work. I just found this site after getting screwed at a dealer for some work on my 92 pickup. Thus, I need to get my hands dirty and do some work myself.

Problem:

I have gone through 3 batteries in the last 2 months. Luckily they are under warrany and they replaced them. I need to know if there is somehting that can be burning up the battery? I took it to Checker for the free test on the battery, alternator, etc... He said the battery was low, thus I took it in and replaced it. He said the alternator was ok?? But I thought I would turn to you all as you seem to know what you are doing.

What should my next step be?

Thanks

 

check it yourself.

make sure the terminals are clean before you install it. Check the voltage at the batt with the engine off (should be 12.something). then check it with the truck running should be 13.8ish. If its not then its not charging.

If thats good then you could have something draining the battery when the truck is off

 

I haven't done it in a looong time so I may be a little off base-but-if you put a multi meter between the negative cable and the negative post on the battery and voltage (either negative or positive, I can't remember) is present you have a short. Then you can pull fuses one at a time to isolate the circuit the short is on.
Hey, its a start.

 

The alternator uses an electro magnet to get current to flow through the field. The battery supplies the current to the electro magnet. If the truck was run with a low battery in the past, and with two replacements, that is likely, the electro magnet does not work properly, and the alternator tries to generate current without a full magnet. This causes the alternator to overheat and die. Mr Alternator does not like a low battery.

 

The alt uses its own current once it gets going, it just needs a little to get going, so I doubt that's the issue.

 

Alex, I disagree. The alternator needs pretty strong voltage to work. Also, I would not be surprised if the battery was not run completly flat somewhere in this saga.

 

I dont doubt that the battery was killed somewhere in there.

I'm not an electrical engineer, but in my class in marine systems (mostly electronics) I was taught that you just need a little current to get it going, just enough to create enough EM force to induce a current in the stator, which can then be fed back through the system to create an ever larger EM force in the rotor->more current induced in the stator. until the voltage regulator limits it.

that was written confusingly, but that was my understanding.

The current the battery can produce is more important than the voltage

 

As silly as this seems, I had a battery go dead for no apparent reason. After thorough inspection of the motor and much frustration ...... the interior light was on, that's it. The thing was so dim I never noticed. So hey, give it a look!

 

new brushes on the alternator maybe??
is your brake/ batt light on???

if so you brushes are prolly worn
pm this guy
https://www.yotatech.com/members/30002.html
$15 for new brushes

 

Advance or autozone can run a free electrical system check that (if I remember correctly) can tell you if your alternator or battery or something else is not acting properly.

If you are having dead batteries then most likely there is a small drain somewhere. I have seen things like trunk light or glovebox lights that have stayed on (hard to tell unless you are in there).

 

this might be off base but....
There's a practical joke going around that if you put a dime in the cigarette lighter, it'll short it out and drain the battery slowly. It's not something one looks for when trouble shooting but....who knows. Maybe you have comedian friends.