Originally Posted by siberian

A similar thing happened on the wife's 2020 Macan AGM battery. A month old and following a weekend of not being driven, everything was dead. Nothing worked. Won't bother with recounting evertying I tried, as it was extensively covered in the Macan forum but it took near 4 days on a CTEK AGM battery tender to slowly bring it back to life.

No idea what happened but a couple of months later, the headlights started strobing - no idea why. Had to flat bed the car to Anchorage 375 miles away and since the dealer couldn't find the problem they were told by PNA to just reset the system. I would truly hate to work for a company that doesn't explain anything and simply tells you to reset; don't think, just do what we tell you.

No clue why a battery on a new car that had just driven up from Anchorage 375 miles would do this nor the subsequent problem. But the Macan and 992 if not driven more than 2 days are on their respective CTEK chargers, the only one I never have any issues with is my 2008 V8 Touareg on a regular Interstate wet cell battery. Oh and the AM band works...

siberian

Originally Posted by siberian

It's time we all migrated to 48v systems...

siberian

Originally Posted by Mikster

It says on page 4 of the 31/20 Service Bulletin pdf above:

If a standard AGM battery is installed in the vehicle, a warning message will be displayed because there is no LIN communication. The power supply network switches to emergency operation.

Implying maybe there is indeed a limp-home, fail safe mode to use non LiOn batteries, in a pinch.

M

Originally Posted by German1967

Same here: not driven for as few days and I connect the CTEK. I wonder, if the battery capacity is just inadequate for the performance needed? If I am not mistaken the 992 AGM battery is 70Ah. The one in my 4-cyl X3 is 105Ah.

Originally Posted by Antigravity

70Ah of Lithium is a massive capacity actually for a Car being that it holds much more energy density than Lead/Acid. I have to assume the Parasitic draw on these Cars is extreme to be draining a 70Ah Lithium over the course of a few days. I know the Ford Mustangs and many other manufacturers have their cars set to update, and reach out to Ford, or whomever if you connect you car to any wifi.... We saw that when we had a few of our Battery Trackers connected to some of these Cars and it created a fairly large draw for about 15 minutes around 2 in the morning every few days. I had a 991 RS and it obviously didn't have that going on, but perhaps the 992s do.... the bottom line is if a 70Ah Battery is draining in a few days there is a massive draw on the battery.

Originally Posted by jpoint

I don't own a 992 but thought I'd share a recent experience reviving a friends car that appeared completely non responsive. That means nothing from the remote fob, no dash lights, no frunk latch access, nothing. I'm posting this because - assuming the car is locked - you won't have access to the owners' manual that explains any of what follows - like how to get into the car to get the owners' manual. The first step of using the emergency access key inside the remote fob to open the door was pretty straight forward. There's not much room to insert the key under the driver's side handle so you have to fully extend the handle to get the key inserted. You can unlock and get the door open but if you close it - remember the retracting window won't function so you'll bang the window against the weather stripping. Since the frunk release is electronic you'll need to get power to the car to get anything to open. Following the owner's manual - you pull a cover panel above the driver's side foot rest to reveal a fuse panel that has a red jumper plug that extends out of the panel when you pull it gently. It will subtly click when fully extended. Using this plug you can attache a jumper box or battery to provide enough power to open the frunk. The plug accepts the positive side of the jumping source - you can use the door hing for the ground. When properly connected - the tail lights blinked. This set up will NOT provide enough power to start the car ONLY open the frunk. Here's the odd part - on this car the frunk would not open when jumped using the switch on the door threshold. We ended up having to use the key fob button for the frunk. This might be the method for all cars - I don't recall what the manual says. Also - on some jumper boxes (digital) the box may give a message that the battery is protected. If so - disconnect the jumper box and reconnect it.

Even at this point the car still appeared to be completely dead - except for the blinking tail lights. However, when the jumper box was attached to the battery the car came alive and was able to start - even without the jumper box. SOOOO - what happened. I'm not sure but I think the battery tender that was on the car caused the lithium ion smart battery to go into protection mode - essentially shutting down the car. Once awakened - the battery actually had a full charge. In all of this - the only part that wasn't clear was the need to use the key fob to open the frunk instead of the frunk switch on the door threshold. I don't know if that was because the fob was too far from the car when we tried the threshold switch or if I missed something in the manual that said use the fob button NOT the switch. Maybe no one else will ever need this but we were about to have Porsche service come and pick up the car. The reason I persisted is because - without power to the car - you also can't get it into neutral to roll it onto a flatbed.

I also suspect that I'd be pretty frustrated if my new 992 went into full sleep mode with what should be a fully charged battery. It also appears these cars need a battery tender that is switchable to Lithium Ion mode. Really neat cars with LOTS of tech to understand. . . . and maybe a bit of "mind of its own".

Originally Posted by jpoint

I'm posting this because - assuming the car is locked - you won't have access to the owners' manual that explains any of what follows - like how to get into the car to get the owners' manual.

Originally Posted by rhr992c4s

When connecting the booster pack to the post in the fuse panel, make sure to connect the ground to the exposed metal loop that latches the door. Don’t use the door hinge, it is painted and may not work for ground. A noco booster has enough juice to open the frunk.

Originally Posted by Mikster

This is annoying tech from Porsche.
I had my battery go into “sleep” mode for the SECOND time, on a brand new battery Porsche had previously replaced under warranty.
I did all the steps above.
One caveat: that stupid red fuse/attachment point in the fuse box will easily retract into the fuse box if you are a bit clumsy. And then it’s impossible to pull out without something like a fuse puller or, in my case, a paper clip.
I ended up trying to get the frunk open using a NOCO brand portable boost battery. No go. Didn’t work. Not enough juice it seems. I had to rely again on Porsche roadside assistance. They got the frunk open easily. Battery then boosted, car started, and this time no battery PCM error lights.
What I can’t understand is what caused the battery to lock down in the first place. I had just driven the car a few days prior.
Certainly frustrating.
M

Originally Posted by achilleas101

which Noco boost did you use? Did you hook uo the neg terminal to the nattwry or the poat by thr driver side? And did you let it sit, hooked up to the battery, turned on for 30 seconds+ before trying to start?

Wondering because i got the Noco XL GB50 which has 1500 amps, so curious if thats not enough if the time may come for me to need it.

It's disheartening to see this post, i saw your post in the other thread. I have an appointment to get my car checked out as I'm still getting the low battery warning even though it seems to be operating normally. So i hope its juat a bad battery (or bcm or warning indicator that is part of the battery) and not something that will happen again with a new one.