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View Full Version : Volt/amp question...

martopg
02-25-2003, 01:20 AM
Ok, I've been having some problems lately and I believe there is somethin draining my battery when the car is off... I checked the voltage right after driving it, and it was 12.79. about four hours later the voltage was down to 12.45. What's the battery supposed to be at and how low is 12.45? How high does the voltage have to be to start the car?

I also measured the current going from the battery to the cable when the car was off. I had it vary between 60-75 milliAmps. Anyone know if this is normal? If not, could someone do me a favore and measure theirs? (I just put one end of the multimeter on the battery terminal and the other on the battery cable, after i disconnected it, of course). Thanks a lot!
iceman
02-25-2003, 01:44 AM
It is very normal for the battery to read around 12.0-12.5 volts when the car is off. Most batteries are made to output 12 volts... However when the car is on, your alternator is suppying your 14.4-13.8 volts.

Milliamps of current, I wouldn't worry about... If you can leave your car parked for overnight, even a day or two, and you have 0 starting problems, I wouldn't be worried.
martopg
02-25-2003, 01:58 AM
Well I have had starting problems and that is why I am asking...
99GrandAMSE
02-25-2003, 06:53 AM
Originally posted by martopg
Well I have had starting problems and that is why I am asking...

Do you have an amplifier? With a little trial and error or removing fuses, you should be able to locate an excess battery draw :)
martopg
02-25-2003, 05:47 PM
Nope, no amp... all elctrical parts are bone stock except for the headunit and the front speakers, and neither of these are very power-consuming.

I guess I'm just trying to figure out if it is normal for the current to be around 60-75mA when the car is off... anyone else?
99GrandAMSE
02-25-2003, 06:13 PM
Here is some test procedures for you ...
99GrandAMSE
02-25-2003, 06:13 PM
Yet another ...
martopg
02-28-2003, 03:35 PM
Hmm... could someone better explain to me steps 5-7 in this guide (first file)...

"5. Connect the negative battery cable" <-- i think i can do that...

"6. Remove voltage from the PCM memory" <--hmmm? how do you do that?

"7. Connect the milliammeter between the terminals" <-- does this mean between the negative battery terminal and the negative battery cable? or somethin else?

Thanks a lot!