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Discussion Starter #1
Each morning the car is hard to start. Acts like a dead battery. It seems to have gotten worse lately....it won't crank at all after about 12-14 hrs.

Lights dim when I crank it. Battery measures 12.4 volts.

Adv Auto says the battery is fine and alternator is too.

With the key off, it drains 0.25 AMPS. Is this reasonable/normal? I am not running any aftermarket electrical stuff but an in dash stereo.

When I pull the 40A fuse (12FL) in the engine bay, the drain reads 0. I have systematically pulled each fuse under the dash, but cannot get it to read 0 however.

I was assuming I had a drain somewhere, but I am beginning to suspect that the battery is not holding the charge. I would have though Adv Auto would have caught that though.

I am curious why the 12FL fuse will kill the drain, but none of the under dash fuses will. Any ideas?
 

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WOT Junkie and avid corn burner
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Hmm, my Mustang did something similar. It had gotten to the point that I had to jump start it every time. Bought an Optima dry cell battery, and all was cured. It seemed I had a drain too. However, a bad battery is not your problem since you said it checked out okay. Ugh, I hate electrical stuff. Hopefully, some one else here can help ya out.
 

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Discussion Starter #3
i charged up the battery this morning and then left it disconnected all day. its dead now. so i dont think the battery is holding a charge, regardless what adv auto says.

i still would like to know if 0.25 amps is normal drain for key off. does anyone know?
 

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WOT Junkie and avid corn burner
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That would make sense. The Anti-theft is always hot. Same goes for the locks, radio clock, dash clock, and lights. Worse comes to worse, if you buy a new battery, you'll know for sure it's not the battery. The only reason why I bought the Optima battery was because it was cold outside, and I didn't want any reason to jump start the Mustang when it's below 20* outside. I think the water was starting to freeze in my old battery.
 

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I would think .25 amp is normal to power the memory in the radio, clock, security system etc.

.25 amp is nothing, a good battery should be able to handle that for weeks. If you disconnected and it is dead, then there is no question the battery is not holding.

A single bulb like in the glove box will draw about 1 amp. Take it to a different auto parts and see what they say. The tester where they but it in a box is usually better than the hand tester.

I had a battery from O'Riley that I was sure was bad and under warranty, so I took it back. He said it was good and not enough amps for my car. I told him they were the ones who sized it and it worked fine for 2 years.

Ended up just buying a new battery somewhere else and it has been fine for a couple of years so far.
 

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Bill,

How are things in Savannah?

You may want to check the alternator output voltage while you are driving around especially at night (with the lights on of course) when the alternator should be able to take the voltage up to the 'float' which indicates full charge around 13.7V to 14.0V for 'regular' automotive batteries. Deep Cycle batteries are probably higher because of the other metals alloyed into the plates.
You may want to check the alternator brushes for wear and the slip rings for wear and 'roundness'. The voltage regulator charging set point would have been checked earlier when you did 'float voltage test' right?

Winston.
 

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The test for a bad battery is to fully charge it, after checking the water level. (distilled only!)

Let it sit overnight, as you did, disconnected, and measure the voltage. Be careful not to shake it up; it will affect the reading.

It should be over 2.2V/cell; 6x2.2=13.2 The higher the voltage, the better the battery. It should never be higher than 2.3V/cell after sitting overnight.
 

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Discussion Starter #9
Hey guys,

Thanks for the help. It was definately a bad battery. Numbnuts at advanced auto misdiagnosed it....I think that threw me down the wrong path. Occam's razor eh?

New battery and all is well.

Thanks
Bill
 
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