Battery Issues

[Synned]

Whats up guys...
So I havent been able to be with my stang a lot since I'm at college, but theres one thing thats driving me nuts.
When I go home, if the car hasn't been started for 2-3 days, its dead. Completely dead. So everytime I gotta take out the **** and jump it.
Anyway, I'm trying to think of what the leak can be. Today I drove 40 minutes somewhere, get out of the car for 10 minutes while my girlfriend is in there listening to music. I go back to start the car, and nothing. Two cranks, at best.
After 40 minutes, wouldn't you think the battery would be sufficiently charged?
So by now its probably practically a dead battery, correct? By dead I mean doesn't hold charge for ****.
I'm thinking the leak is in my alarm system, but how can I know for sure? Just hunt around for exposed/touching wires?

Thanks guys
Joe

 

[94' Five.0]

You can test the parasitic drain by using an ammeter(DMM). Pull off the negative battery lead and put your meter between the bare terminal on the battery and the lead you just took off. Make sure everything is off when you do this test...ignition, dome light, engine compartment light, etc. Now you can pull fuses one at a time to see if anything is drawing abnormal current.

Of course this test is pretty much a moot point if the battery or charging system is faulty. Charging up the battery and isolating it from the system for a few hours would make a good load test more effective. Once you know you have a good battery that can hold a charge you can move on to testing the charging system. Make sure you have 12v on the battery with the engine off and around 14-16v when it's on. If the voltage is lower than 14-16 then try replacing the regulator. If this still doesn't bring you to 14-16v then you may have an issue with the alternator.

 

[HISSIN50]

I like the above test. There's a decent chance the battery simply crapped itself. If it acts dead and then you can put a charger on it for 10 seconds and all of a sudden it acts cool, that's another sign the battery is toast (probably sulfated).

Good luck.

 

[5.0 from 95]

I have the same kind of problem. Sits for days at a time and mine actually drops a cell in the battery. I have tried pulling the ground off and testing it this way and mine never changes on the read out. It reads the same regardless if 1 fuse is pulled or they are all out. Is the regulator part of the alternator or is it a seperate piece? That is the only part I have not changed on my car looking for this ghost?


Paul

 

[HISSIN50]

I have the same kind of problem. Sits for days at a time and mine actually drops a cell in the battery. I have tried pulling the ground off and testing it this way and mine never changes on the read out. It reads the same regardless if 1 fuse is pulled or they are all out. Is the regulator part of the alternator or is it a seperate piece? That is the only part I have not changed on my car looking for this ghost?


Paul

Paul, what is the reading when you test for current-draw?

The regulator is part of the alternator but it is servicable. Quick test if your current draw reading is high: Test it with the alternator charge cable disconnected from the PDC. If the reading drops, there's a chance the alt has a bad diode. A parts store can test this. If the reading stays the same, the alternator isn't parasitic.

Good luck.

 

[Synned]

Thanks for the suggestions guys. I do think its the battery...I'm just going to swing by az and have em test it for free.