Is this a sign of a dying battery? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

tolum · 08-03-2008, 05:14 AM

Guys, since 12 cars, it's my first experience with battery problem, so I'm a little green with those problems.

Battery still in the car and plugged. Engine off
Took a reading direct on battery last night: 11.54 vdc.
This morning, still 11.54 VDC

Before I go and buy a battery charger, is this a sign of need to recharge the battery or need a new one?

The only thing I can tell you, that battery was in place when the alternator failed. Alternator is 3 week old now and seams to charge well (14 vdc). Do you think battery suffer due to the old intermitent running alternator and now need some help to reach and maintain 12 VDC?

Thierry

tolum · 08-03-2008, 06:10 AM

Forget it, I'm on my way for a new OEM battery. I have an electronic volt meter & an amp reader that I normally use for AC. Is there any way I can use my amp reader on the main positive wire that is plug on the battery to look if there is current drawned out of the battery by something in the car? If not, is there another way to see it?

Tks!

blue2000s · 08-03-2008, 06:30 AM

Any auto parts store should be able to run an electrical load test, free, to tell you if it's the battery or the alternator. It sure sounds like the battery to me.

tolum · 08-03-2008, 11:09 AM

Battery change...
Now get 12.25 VDC steady when engine stop.
14.35 VDC when engine idle

Thank you all for your comments and help. Team work is the way to go!

Thierry

Jaxonalden · 08-03-2008, 11:36 AM

Tolum,

You did the right thing. You had a cell going out and even though, with a jump, the car will run-the battery was gone. There is a rule of thumb; 2% degradation (from 100%) per month from initiation (adding the acid). So anyone can figure out the % loss of their battery.

I had the same problem, my OEM battery was weak and was turning the starter over slow. After I replaced it the whole car seemed to wake-up and ran noticeable better.

9eighty6 · 08-03-2008, 06:06 PM

I just had this problem and a new battery will make a world of difference. The Porsche OEM batteries are too costly & not that great. Good luck in your choice!

Gary in BR · 08-04-2008, 11:52 AM

Almost the same topic,

The car has sat for 2 weeks, I know I know, it never sits but the MG needed to get driven.

Anyway, I drive the car Friday night after a few miles the battery and ABS lights comes on, after that the car drives fine. When the lights come on I notice the idle is going a little higher, after I give a little gas the lights go off.

It only happened a few times and all of them where at idle.

I assume a dying battery or alternator.

Hopefully a battery not a alternator.

What do you guys think?

OldBlevins · 08-05-2008, 08:12 AM

Quote:

Originally Posted by tolum

Forget it, I'm on my way for a new OEM battery. I have an electronic volt meter & an amp reader that I normally use for AC. Is there any way I can use my amp reader on the main positive wire that is plug on the battery to look if there is current drawned out of the battery by something in the car? If not, is there another way to see it?

Tks!

Ordinarily the way to check for a drain on the battery is to make sure everything in the car is turned off, disconnect the negative wire clamp from the battery, and put a tester between the clamp and the negative battery post. If there's no draw on the battery, no current will show up.

BUT... make sure you have your Radio Code (if your radio has one). Also, it takes awhile for the Boxster to turn everything off and I'm not as familiar as others in this forum with that element of this test.