My mother inlaw recently started to have a problem with her battery dying. I can jump start the car and then let the car run with out a problem. I took a to the battery and it appeared that the alternator was working fine. The car didn't have a problem starting after that until the third day. The battery was completely dead. So I picked up another battery and the voltage on the battery was 12.65 w/out the car started. A little over 14 volts with the car running.
So I decide to see if there was a voltage leak by disconnecting the negative cable to the battery. Then using the voltmeter I connected one end of the voltmeter to the - post on the battery and the other end to the - cable. (the positive cable is connected to + post) To my dismay there was 12 volts reading on the meter. So my next step was to disconnect the cables on the alternator to see if it was the voltage regulator shorting out, but it wasn't. So then I started pulling fuses to see if I can find the short that way. But there was still a voltage leak some how. So I have all the fuses pulled and even the main relay and there is still a leak.
So my question is if anyone else has encountered this and has found a solution to find the short. I thought of connecting a switch to the battery so when the car is not running it won't drain the battery, but I'd rather fix the problem the right way.
Thanks a lot for reading my post and for any help anyone can give

DragonX

Does she have any kind of audio equipment inside with an amplifier?

Has anything happened to the car before it started having the problem?

No amplifier. The last thing that was replaced was the distributor because of the TDC sensor. But I did disconnect the two harnesses and did not make a difference. Im not sure about how the stereo was put in so tomorrow I was going to take a look and disconnect it.

Yeah, do that. The stereo might use some electricity to remember it's stored radio stations, or something...

Actually, I would be surprised if you DIDN'T have a reading of 12V using your technique.

This is because a voltmeter has a very high resistance- depending on its quality. As a matter, if the resistance of the digital voltmeter is higher than air, then the air itself would behave as a leakage!

In simple, your technique is flawed and does not prove there is any problem!

You should be measuring the current that the battery discharges when the car is turned off!

The car is turned off and the negative cable is disconnect from the battery. The + cable is attached still. You shouldn't get any voltage by taking the volt meter and touching one side to the - post and the other to the negitve cable. I get 12.6 volts by doing that. Witch usually meens there is a short some where. But I have yet to find it and if the batter is left connected it will be completely dead the next day. To me that's some sort of short in the car somewhere.

I'll repeat once again. "Don't measure voltage because a voltage reading is meaningless."

If I take my voltage meter and measure voltagte to ground on a healthy ungrounded 24VDC system, I get +12VDC on positive to ground and -12VDC on negative to ground. This reading is because my voltmeter is sensitive.

If on the other hand, I measure the current to ground, I get 0A.

Voltage leak is just potential and does not use any power. Current uses power and drains batteries. You can have voltage without current but you can't have current without a voltage!

You need to check current (amps ) you should have blow 0.04 I think which is enough to store memory etc.

Connect your voltmeter the way you are but use the amps setting and connections not voltage

Hi,

I have the same problem.
I had my distributer replaced, and since then, the battery goes dead very often.
Even a 5mins turn on of the head lamps, without turning on the engine, would discharge the battery.

I am thinking of replacing the battery as it may be old.