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Posted: 9/24/2004 3:19:46 AM EST
How many volts should an automotive battery put out on it's own, without the vehicle running?
Link Posted: 9/24/2004 3:23:08 AM EST
[Last Edit: 9/24/2004 3:24:23 AM EST by gotm4]
Usually about 13.8volts. But the voltage varies and what you really need to know if its working correctly is the cold cranking amps.
Link Posted: 9/24/2004 3:47:28 AM EST
Most of the time it is higher, 14 to 14.5 volts. 13 is OK. 12 is low. Shut off your engine, turn on your headlights for about 30 seconds, turn off, measure the battery. If it has a good charge, it should remain over 12 volts.

Sears will check it for free.

If you need a battery, buy an Optima (Sams, Costco, PepBoys)
Link Posted: 9/24/2004 3:51:21 AM EST
A more accurate way of seeing what kind of load there is on the battery. Use an inductive (clamp) style Ammeter.
Link Posted: 9/24/2004 4:23:38 AM EST

Originally Posted By bung:
How many volts should an automotive battery put out on it's own, without the vehicle running?



A fully charged batt. with the surface charge removed will read about 12.6
Link Posted: 9/24/2004 5:39:33 AM EST
[Last Edit: 9/24/2004 7:50:18 AM EST by warlord]

Originally Posted By bung:
How many volts should an automotive battery put out on it's own, without the vehicle running?


Each cell puts out 1.2V. If you have six cells, that's 12.6V.

When the vehicle is running, it should be about 13.8-14.5V.
Link Posted: 9/24/2004 7:35:36 AM EST
It wouldn't start this morning. I put the voltmeter to it and it read 10v. I can;t think of any reason that the battery would be flat this morning (nothing left on over night). It looks like my alternator may be bad. I'll recharge the battery and then check the output of the alternator.
Link Posted: 9/24/2004 7:44:57 AM EST
Pull one cable off the battery (I recommend the black (-) side). Put a voltmeter between the connection on the cable you just removed, and the terminal that it was just connected to. With your keys out of the ignition, and everything 'supposidly' turned off, if you read any voltage at all, you have a small current leak somewhere inside the car. If you dont have a voltmeter ($10 from any autoparts store?), then two wires connected to these two points, and touch the 'open' ends of both wires to your tounge. You will taste a tangy-sour. That's the taste of electricity.
-I can hear it now... a bunch of wussy's telling me "Oh, that's just dangerous!"...
Link Posted: 9/24/2004 7:50:35 AM EST
Link Posted: 9/24/2004 7:50:59 AM EST

Originally Posted By bung:
It wouldn't start this morning. I put the voltmeter to it and it read 10v. I can;t think of any reason that the battery would be flat this morning (nothing left on over night). It looks like my alternator may be bad. I'll recharge the battery and then check the output of the alternator.



How old is your battery? I usually replace mine every 4 years if they haven't gone bad by then. Just so one day I'm not in a position of it won't start in the morning. Cells go bad in batteries. It'll make it not hold a charge. With your car running check the voltage.
Link Posted: 9/24/2004 7:54:08 AM EST
Link Posted: 9/24/2004 7:56:02 AM EST
The battery is about 2 years old. Yesterday while driving I noticed the truck "stumbling". It felt like it was losing power. Now, this morning the battery is flat. I hope that it's related. I can barely afford one problem right now.
Link Posted: 9/24/2004 7:57:05 AM EST
Link Posted: 9/24/2004 8:02:23 AM EST

Originally Posted By mike_of_austin:
Pull one cable off the battery (I recommend the black (-) side). Put a voltmeter between the connection on the cable you just removed, and the terminal that it was just connected to. With your keys out of the ignition, and everything 'supposidly' turned off, if you read any voltage at all, you have a small current leak somewhere inside the car. If you dont have a voltmeter ($10 from any autoparts store?), then two wires connected to these two points, and touch the 'open' ends of both wires to your tounge. You will taste a tangy-sour. That's the taste of electricity.
-I can hear it now... a bunch of wussy's telling me "Oh, that's just dangerous!"...



Butttttt... If he has a clock, or any radio with channel memory, it will show voltage. You need to check the current draw.
Link Posted: 9/24/2004 8:03:51 AM EST
"hell, i'm overjoyed if a battery goes three years for me"

Buy an Optima. I have two. One is 6 years old and the other is 4 1/2 years old. Best battery you can buy IMHO.
Link Posted: 9/24/2004 8:04:39 AM EST
Dead cell! Take it to the bank!!
Time for a replacement.
Link Posted: 9/24/2004 8:06:45 AM EST
-Yea... what I did one time, was put a wire (actually, it was a coat hanger), inside a spark plug boot, then told me friend to (hold this so that the "this black cable looking thing", doesnt touch any part of the engine... while I try to start it.... HehehHEheHHEhHehehe

- oh, and I always loved the, put your ear near the radiator while I operate the ' ____ ' from inside the car, and see if you hear any bubbling sounds... ( HONK! )

//I do love a good prank.



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