Normal Battery Voltage

[scchang]

Originally Posted by FSETH

Do the numbers fluctuate when you are testing at idle? If they are changing more than half a number or so, you are more than likely having an issue with your voltage regulator/alternator.

Good question. There is a little fluctuation, no more than 0.2V though. While driving, I'm seeing 13.4-13.6V.

What I don't understand is how it could start after sitting for a couple days, be driven 12 miles, sit for five hours and then not start.

Then, after being jumped, driven home another 12 miles, sit for a couple days and start again.

It doesn't make sense that this little bit of driving would adequately charge the battery, but what do I know!

[FSETH]

Originally Posted by scchang

Good question. There is a little fluctuation, no more than 0.2V though. While driving, I'm seeing 13.4-13.6V.

What I don't understand is how it could start after sitting for a couple days, be driven 12 miles, sit for five hours and then not start.

Then, after being jumped, driven home another 12 miles, sit for a couple days and start again.

It doesn't make sense that this little bit of driving would adequately charge the battery, but what do I know!

The alternator on my e36 fried out, I replaced with a remanufactured unit and noticed that my lights (interior/exterior) were pulsing a little. Went down to Autozone and had them test the alternator and they found it was fluctuating about 0.50 - 1.0. Ended up being the voltage regulator.
I put in another remanufactured alternator and all is well.


I just replaced the battery in our X a few weeks ago. One morning (after sitting all night) it started up fine. Then my wife shut the car off at a gas station about 2 miles down the road and the car would not crank. I was a little surprised it started normal just a few minutes earlier then would not start at all in such a short period of time. There really wasn't much of a warning that the battery was loosing charge.

[scchang]

I'm Autozone-bound this afternoon...

[FSETH]

Originally Posted by scchang

I'm Autozone-bound this afternoon...

Well, did you find out anything? They will test your battery and alternator on the spot with a small hand held load tester. It only takes a few minutes as you may already know.

[scchang]

Originally Posted by FSETH

Well, did you find out anything? They will test your battery and alternator on the spot with a small hand held load tester. It only takes a few minutes as you may already know.

I'm on Pacific time, still at work. I'm going as soon as I get through and will post back. Good to know that it is a quick process! Do they access the battery directly, use the under-hood terminals or do something else?

[FSETH]

Originally Posted by scchang

I'm on Pacific time, still at work. I'm going as soon as I get through and will post back. Good to know that it is a quick process!

Ah, west coast...

Yeah, it is a quick process. They connect the tester to the battery jump contacts under the hood while the engine is running. That is pretty much it. They can switch back and forth between your battery and alternator to see what is going on.

[scchang]

Originally Posted by FSETH

Ah, west coast...

Yeah, it is a quick process. They connect the tester to the battery jump contacts under the hood while the engine is running. That is pretty much it. They can switch back and forth between your battery and alternator to see what is going on.

Nice. Free information, such a deal!