Ok, is my alt going crazy or is my battery just retarded. When I start the car and disconnect the battery, the voltage says 12v (w/ only dash and parking lights on). However, when I connect the battery, the gauge drops to about 10 and stays between 10-11v. and the lights and gauges flicker. I know think that my battery is going bad because its not too cold here in Fort Lauderdale, FL (50 degrees is freezing for us) but even still my battery is dieing overnight. Its died 3 times so far over the last two weeks. What should I do?

 

That battery probably has an internal short.
Also you may have some intermittant/weak primary cable connections.

VOLTAGE TEST
Engine running, headlights & heater fan on high:
Alternator post to alternator frame = 13.5-14 volts (verifies the alternator output)
alternator post to battery (+) = 0 volts (verifies the primary + wire)
alternator frame to battery (-) = 0 volts (verifies the primary ground)
Turn off the motor, but leave the lights on.
Battery (+) to battery (-) = ~12.5 volts and holds steady. (verifies battery)

 

OK, I dont have a voltometer right now, but I know that Im not getting 12.5v when the car is off. Thanks. I just didnt know that a battery could have an internal short like that. When I finish work, if the car starts, I'm gonna go home and check the voltages like you said. Thanks again

 

Got a Harbor Freight store down there?
They have a basic DVM for about $6.
A cheap analog (needle type) voltmeter will do, and is even better for checking the TPS.

 

Yep, thats what I was getting to next. I am having idle problems but cant find any vacuum leaks. Yet, once my car gets to operating temp. it idles at like 600rpm and when you try to brake to a stop the car tries to stall or actually does. I think the problem, since pressing the breaks make it worse, might be with the brake booster, but I cant find any vacuum leaks. Do you think that if the booster was going bad it could cause this? Thanks for all the help.