Good info and you're right, these rolling computers can do some odd stuff..

Mine is fine know, took some measurements over a week, was dropping the voltage by about 0.01 to 0,02v each 24 hour period, looks like it was either just a bad battery or something didn't shut off when it should have.

 

Hopefully this thread isn't old enough for this to be considered a resurrection...but my battery is starting to show signs of EOL. Chassis failure indications, slow cranking. I checked the age this morning - November 2009! That thing has done it's job!

 

Sounds like you got your money's worth
incredible that you are still on the original battery

 

Since I posted back in October I’ve been keeping track of things. To recap MY 2018 971 P4 new in service 11/15/18, battery completely drained dead after sitting in garage 8/19 locked after ten days (away on vacay). Flatbed to dealer after discovering, their response was that everything was “ok”. Yeah I know, ten month old battery croaks inside garage locked up in summertime with no draw.

Anyway, since then I’ve been keeping an eye on this and noted the following: starting voltage is consistently 11.8 and less volts and the only time it is over that is when car is restarted within a few minutes of being turned off. When driving voltage is constantly 14.7 to 15.1 volts and since August has only dropped to 12-13 volts once while driving once (four highway trip). I’ve double checked voltage with a good multi meter and voltage matches dash voltmeter. It’s almost as if battery will only hold a charge to 11 volts, or below threshold of “charged” voltage level causing system to constantly charge.

so my question to the group is what are your experiences?

hank

 

Actually there is always a draw on the battery in these cars especially if you have something like enter and drive, but if they didn't replace the battery it is probably less than stellar as AGM batteries really do not like being completely drained.

 

I didn't think a one time drain would have that effect, but you have given me something to consider. The good news is the car is going in for transmission warranty work after Christmas, so I'll add this to the list.

nb If anyone saw the earlier version of the post, I realized afterward I was comparing deep cycle AGM performance to starting battery AGM, two entirely different critters.

 

Hey Hank, something I wanted to mention as well is that we do have a battery tracker that might help you see what's going on when the car is sitting as well as when it's being driven in a little more detail, it's a nice little tool you can use to see what's going on with parasitic draw as well as measure the output during start attempts. Nice thing about it is that it will retain the data for 30 days so you can visually see what's going on with the voltage over that time and then it sends the info via bluetooth to an app on your phone.
https://antigravitybatteries.com/pro...ker-lead-acid/

 

Had the same experience with my 2010 Panamera S last year when I couldn't start the car and Battery measured very low Voltage.
Replaced the Battery with a new Sears Diehard. Within 2 Weeks I had the same problem on the new Battery - No Start and Low Voltage.
Put my Ammeter in Series and it showed 8 Ampere Draw with the Car OFF. Flat bedded Car to Porsche Dealer and asked them to
Recharge and re-install the Car's programming. After doing that, Dealer said Everything checked Normal. Drove home with no further problems.
I concluded these rolling Computers masquerading as "Cars" eventually "Crash" and require Re-Booting. after doing all sorts of "funny-stuff".

 

Seems like a good idea, however I tried to buy one using PayPal. After going around three times to PayPal and returning to order page with no error messages, or button for “place order”, I called it quits.

 

Hello Hank B.

I experienced a similar issue with my 2018 Pan Hybrid. Measures only 2v and will not take a charge.
So I will have to call and arrange for flatbed. Did they actually replace your battery? Curious if there is
a way to open the hatch with no juice on the 971s. The 970's supposedly have a release inside.
Looks like the Grinch got to my car..

Happy Holidays
Doug

 

Battery wasn’t replaced, I’m working on that now. As for the hatch I couldn’t find a mechanical release. The good news is there are terminals under the hood in the engine compartment for connecting jumper cables/jump battery. If I needed to raise the hatch I suppose in could plug in a battery through the cigar lighter and use that to power the hatch lift. I’ve done that in the past with electric boat hatches.

H

 

Replaced the original Batteries in my 2014 Mercedes AMG E63S a few days ago with New Mercedes Batteries.
Large Battery was $ 320, Small Battery was $ 215.
To my surprise, both NEW Mercedes Batteries now include a LIFETME Warranty from Mercedes.
They are replaced free of charge as long as the Battery Buyer remains the owner.
Be nice if Porsche could do the same with their Batteries.