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Battery 01 C2

 
Old 05-10-2019, 01:34 PM
  #46  
peterp
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Originally Posted by NickHolloman View Post
I put an Autozone battery in the car last year some time and I noticed the other day when I drove it that cranking was slugglish. By the end of the day it was dead.
Were you using the rear defroster that day? The more I think about it, the more that makes sense as the cause. If the defroster relay is fused, the interior defroster indicator light would still go out when you shut off the car, and it would not turn back on when you restarted it, but the defroster would keep running whether the key is on or off because the high-current supply side of the relay is stuck on.
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Old 05-10-2019, 04:15 PM
  #47  
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Originally Posted by peterp View Post
Were you using the rear defroster that day? The more I think about it, the more that makes sense as the cause. If the defroster relay is fused, the interior defroster indicator light would still go out when you shut off the car, and it would not turn back on when you restarted it, but the defroster would keep running whether the key is on or off because the high-current supply side of the relay is stuck on.
I don't think I've ever used it to be honest. definitely not lately, I live in Alabama. Though, this did seem to start after I got it our of the body shop, maybe they flipped something
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Old 05-10-2019, 04:15 PM
  #48  
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Originally Posted by peterp View Post
In the old days, you could pull fuses one-by-one to find out where the current drain was, but I don't know if that is such a great idea for newer cars with ECU's. The only thing I can think of that would draw that many amps without any visible sign is the rear window defroster. The defroster should shut off with the key, but if the relay is stuck then maybe it would stay on. There rear window would be slightly warm if that is the case.
Def on the list to check now
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Old 05-14-2019, 11:35 PM
  #49  
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Ok update. Havenĺt had much time lately so today I had a few minutes and I jumped it off. Let it run for a few minutes and checked the alternator. Battery was showing 13.9-14.1 consistently with no ac or stereo on. After turning the car off the battery was only at 11.3 and I watch it tick down to about 10.5 before I stopped watching (about 30 secs).

Thoughts?
How do I test the cable that runs from the alternator to the battery?
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Old 05-15-2019, 08:03 AM
  #50  
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I just had a battery replaced, thinking back a few weeks ago I should have realized that the engine was cranking slowly.... Sunday we were going to take a drive and have lunch along the beach...

click.....click....click....DED....I looked up the battery, replacements they ran from $150 to over $200

OK, I can do that, wife says call and have it done Mr Macho man...you ain't as young as you used to be

Called AAA and they would replace the battery for $180...so, they come to you, check the system with a computer, provide and install the battery, use a device that saves your programming, and give a 3 year replacement and 3 additional years of pro rated guarantee .. AND no breaking my back lifting a 50+ # battery out and bringing to back to the store for credit.....

DEAL....CANT BE BEAT

Listen to the wife....she's right....

And...if your battery is 5 or 6 years old just replace it,,,because you know it's "on it's way out" and it will generally leave you stranded at the worst possible time....cheap insurance....
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Old 05-15-2019, 12:30 PM
  #51  
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Originally Posted by NickHolloman View Post
Ok update. Haven’t had much time lately so today I had a few minutes and I jumped it off. Let it run for a few minutes and checked the alternator. Battery was showing 13.9-14.1 consistently with no ac or stereo on. After turning the car off the battery was only at 11.3 and I watch it tick down to about 10.5 before I stopped watching (about 30 secs).

Thoughts?
How do I test the cable that runs from the alternator to the battery?
You really need to have a professional check it out because they have the equipment to identify the cause very quickly. Just about any competent that sells batteries can do that -- it isn't a specialized Porsche-specific process to identify the cause. If you have AAA, that would seem to be a good solution given the comments that they do analysis to figure out the cause before taking action. I assume with AAA you could choose to decline the battery replacement if you wanted to buy it somewhere else.

If you have a dead cell in the battery, it will likely still jump start and show higher voltage due to the alternator output, but when when you shut off the car it will show voltage a little over 2 volts down. I would try disconnecting the battery from the car, then check the voltage. Then charge the battery while still disconnected and see what the voltage goes up to (if you have a faulty cell, it will stay low -- or maybe go to normal voltage but then drop down again with a moderate current draw).

Previously you measured a current drain when the car was off (is that still the case?), but that would not affect your last scenario very much assuming you measured the battery immediately after shutting the car off.
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Old 05-15-2019, 02:46 PM
  #52  
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Originally Posted by peterp View Post
You really need to have a professional check it out because they have the equipment to identify the cause very quickly. Just about any competent that sells batteries can do that -- it isn't a specialized Porsche-specific process to identify the cause. If you have AAA, that would seem to be a good solution given the comments that they do analysis to figure out the cause before taking action. I assume with AAA you could choose to decline the battery replacement if you wanted to buy it somewhere else.

If you have a dead cell in the battery, it will likely still jump start and show higher voltage due to the alternator output, but when when you shut off the car it will show voltage a little over 2 volts down. I would try disconnecting the battery from the car, then check the voltage. Then charge the battery while still disconnected and see what the voltage goes up to (if you have a faulty cell, it will stay low -- or maybe go to normal voltage but then drop down again with a moderate current draw).

Previously you measured a current drain when the car was off (is that still the case?), but that would not affect your last scenario very much assuming you measured the battery immediately after shutting the car off.
I took the battery out and had it tested and it was fine.

Ill try your suggestion of charging it again out of the car and testing it. I think last time after it was charged I threw it in and it started the car without checking it.
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Old 05-15-2019, 04:31 PM
  #53  
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Yea it kind of sounds like u have something draing the bat not a charging issue. U may need to get an amp meter and pull one fuse at a time untill the amprage drops off when the car is not running. No real easy way to find a random draw
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Old 05-15-2019, 04:44 PM
  #54  
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Originally Posted by NickHolloman View Post
I took the battery out and had it tested and it was fine.

Ill try your suggestion of charging it again out of the car and testing it. I think last time after it was charged I threw it in and it started the car without checking it.
If it started on the battery alone last time after charging, you probably don't have a bad cell. You can measure voltage easily with a meter, but I don't think it's possible to measure amperage unless you have a serious meter (with battery cable size leads). You really to take the whole car and get the charging system tested rather than just having the battery tested.

Last edited by peterp; 05-15-2019 at 05:31 PM.
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Old 05-15-2019, 05:42 PM
  #55  
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He is getting over 14v when the car is running so its charging. The issue seams to be that something in the car is "on" with the car off and its pulling the battery quickly. This meter should work for dc amps. I think home depot and lowes both sell a version of this too.

Meterk Digital Clamp Meter Multimeter 4000 Counts Auto-ranging Multimeter with AC/DC Voltage&Current, Resistance, Capacitance, Frequency, Diode, Hz Test, Non-contact Voltage Detect
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Old 05-15-2019, 06:13 PM
  #56  
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Originally Posted by De Jeeper View Post
He is getting over 14v when the car is running so its charging. The issue seams to be that something in the car is "on" with the car off and its pulling the battery quickly. This meter should work for dc amps. I think home depot and lowes both sell a version of this too.

Meterk Digital Clamp Meter Multimeter 4000 Counts Auto-ranging Multimeter with AC/DC Voltage&Current, Resistance, Capacitance, Frequency, Diode, Hz Test, Non-contact Voltage Detect https://www.amazon.com/dp/B0721MKXBC..._3Jh3Cb0ASKPKN
That is a very cool meter -- have not seen a clamp-on that does DC current. Still, I recommend a charging system analysis. I think Autozone does them for free.

The symptoms don't really add up. That last showed that the voltage dropped immediately (if I understood his post correctly) after shutting off the car -- nothing can drain the battery that quickly without smoke involved I would think. If the voltage pops back up after removing the battery terminal, then maybe something is dragging it down, but I don't see how voltage could be dragged down without smoke somewhere. On the other hand, since he jumped it, rather than charged it, maybe the battery voltage was already low and he did not run it long enough for it to charge up (that would explain the result in OP's last update).

A previous post stated that the it had a 7 amp drain when shut off, but even that heavy load would take a while to drop voltage down. If that 7 amp drain is still happening, I maintain my belief that it's likely that the supply side of the rear defroster relay is fused on (because that's the only thing I can think of that will suck up significant amperage without any detectible sign).

All of this would be answered with a free analysis by Autozone or any other competent shop.

Last edited by peterp; 05-15-2019 at 09:02 PM.
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