Group, in these times where some of us are not daily driving their 992s as often, what is the read in your battery before you start? Mine (AGM, not Lithium) is at 12v give it or take, what I find to be too low.

Trying to get a RL consensus on what is common for the 992. I have the impression that the AGM battery is undersized for this car, if not driven more often. My prior P-cars would sit easily up to 3 weeks and start without issues. Same for beemers and mercs. This car was dead 2 days out of the trickle charger (3 phase 50A). At least I had the presence to hit the trunk button immediately. Dealer found nothing wrong, as usual.

 

Get a battery maintainer. When parked in your garage, plug in. Very simple task.

 

An externally fully charged battery should hold for more than 2 days. That's my issue. Besides, I'm still driving the car, albeit not daily, at least 4x per week, 30 min minimum.

 

That's not enough. It's even covered in your Owner's Manual.

 

Where does it say that in the owner's manual?

Here are the pages from the 992 Manual for both lithium and lead battery care.

 

This is definitely unusual.

My friend's 992 C2S can go for a week sitting in the garage without any issue re: battery. Fires right up.

 

I'm doing exactly like the manual and the warranty manual says - If you drive less than 6000 miles per year you need the tequipment charger. But once charged, 2-3 days is too little for the battery to be dead. It still gets charge and the dealer said - no PIWIS errors, battery took charge. They close the door with that.

It's dropping an average of 0.4v in the first 24-36 hs. As I'm driving, it sits around 15v. When I shut off the car, it goes up to 12.3v. After 24-36hs, it drops to 11.9-12.1v.

From the warranty book:
Your Responsibility for Normal Vehicle Use Your Owner’s Manual (which includes specific recommendations against using your car in certain ways) was written with the assumption that you will use your car only in ways for which it was designed:
• To carry passengers and cargo within specified load limits. (The load limits are specified on labels located in different places depending on your Porsche model. Your Owner’s Manual gives the locations.)
• To be driven on reasonable road surfaces within legal speed limits. Porsche Guidelines specify reasonable mileage to be at least 15 miles / 24 kilometers per day or 6000 miles / 9600 kilometers per rolling 12 months.
• If you drive less than the above-mentioned limits, or in the event of prolonged storage, contact your local authorized Porsche dealer for instructions. (Note: A battery maintainer is available at your local authorized Porsche dealer. It must be used to maintain your vehicle’s battery state of charge if your vehicle will not be used for several days.)


Battery Jump Start If your Porsche vehicle won’t start due to a weak battery, Roadside Assistance will send an authorized service provider to “jump start” your vehicle.
If your vehicle is not driven on a daily basis or has not been started for more than six (6) weeks, the battery may need to be replaced. This will not be covered by Porsche’s New Car Limited Warranty.
Porsche Roadside Assistance can arrange transportation to the dealer for battery service, at your expense. If the Porsche dealer determines that the battery failed due to a warrantable issue, your tow expenses will be reimbursed by the Porsche dealer.
Please remember that proper maintenance of the battery includes operating the vehicle on a regular basis to keep the battery charged and/or utilizing a Porsche Battery Charger/Maintainer.



Helpful Tips Maintaining the Life of Your Battery
• Start and drive your Porsche vehicle on a regular basis.
• After parking your Porsche vehicle, always remove the key from the ignition and lock the vehicle.
• If you drive less than 6000 miles/9600 kilometers per 12 rolling months, or if the vehicle will experience prolonged periods of storage, Porsche recommends using a battery maintainer, available from your authorized Porsche dealer.


Remote Control Standby/Sleep Mode (Sports cars only) In order to extend the life of the battery, your Porsche vehicle will automatically go into a remote control standby/sleep function if it is not unlocked or started within 5-7 days. To wake up/reactivate your remote:
• Unlock the driver’s door at the lock using your vehicle’s key. • Leave the door closed to prevent triggering the alarm system. • Press the lock/unlock button on the remote control. The remote control is now reactivated.
Vehicle Storage Procedures • Fill up the fuel tank. • Increase the tire pressure to 58 psi. • The vehicle should be moved slightly, approximately every four weeks, to prevent flat spotting of tires. • Windows, doors, lids and top must be closed. The air vents should be opened. • Change the oil and oil filter, and run the engine for several minutes. • Check and correct coolant/cleaning solution level as necessary. • The air conditioning system should be in good working condition and fully charged. • Lock the vehicle. • Note: It is not recommended to lift the vehicle, due to the possibility of corrosion on shock absorber piston shafts. The staff at your authorized Porsche dealer will be glad to advise you on the most suitable and necessary storage methods.

 

Are you locking the car in the garage? Where do you leave your key fob??

My battery was replaced under warranty when it was about 18 months old. It can happen. Go to another dealership.

 

Car is locked, keyfob away from it. I'm dreading another dealer due to the distance, but it's going to be the case.

 

Were we not supposed to drive them so often? I am coming up to 16k miles and just came back from some errands in the snow.

 

Ok, so my C4S so far has no issues with battery, driven a couple of times a week, 15 - 40 miles at a time. 650 miles done so far. It’s a lithium lump BUT I didn’t enable the tracker and don’t use the telematics stuff.

I had a loaner C2S convertible for a week. Lead battery, died in 3 days in the garage. Dealer called saying the tracker had been set off and they couldn’t see the car on telematics......

AA man turned up pretty quick, “Porsche, with a dead battery, yeah, I get a lot of these. Something in these cars nails that battery when it isn’t driven!”
Opened the frunk from the pull out in the fuse box, started the car from his jumper box. Asked me to give it 40 minutes running in the drive before switching off.

I’m not saying they drain out only because of the tracker etc, but it sure as hell doesn’t help matters.

 

I suspected that, but the dealer said my car doesn't have a tracker. I wish I could verify that myself, but apparently it's somewhat hidden (I doubt, I trust people's laziness).

The telematics is expired, not missed. My prior 991.2 had it and I didn't have battery issues, even having it parked for 3 weeks several times.

 

Do all of the 2021 911 models have the lithium battery?

 

Well, here, from Europe, is what I can bring to the discussion:

• 992 Turbo S with 60 Ah lithium battery.
• Car is in a garage below ground, so tracker cannot connect to GPS signal or cellular phone network.
• Car sits in a garage for two or three weeks (locked) and starts with absolutely no problem.
• Each time I have put the battery on the Porsche Charge-O-Mat Pro, it has reached full charge in less than 12 hours, which indicates battery was far from "fully dicharged".
• Previously I had a 991.2 Turbo S with a 95 Ah battery; in one instance, it sat over two months without recharging and started with no fuss.

I suggest you peruse the following article on car batteries:

How Long Can A Car Battery Sit Unused?

 

I'm going to find out later today...car has sat locked and undisturbed in high rise garage in Chicago for over a month now...

PS, my little red alarm LEDs by side mirrors are still flashing tho!