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Got a battery warning light. I trickle charge religiously.
Battery holding a 13.4V charge but this is the lithium battery with the integrated battery management module/system.
Car starts fine but I worry that a faulty battery management system might lead to battery drain when parked off a charger.
The fix is replacing the battery because the BMS is part of it, not a separate part or module.
Here's the bad news and why some of you may be waiting for their new 992s and, definitely, why you don't want to have to replace your battery right now.
The battery is out of stock with no eta.
Oh , and it costs $2000.
And Porsche doesn't warranty the battery if you drive less than 6000 miles a year. My dealer, though, is pushing for warranty replacement because technically the battery didn't fail. The BMS did. And the battery was kept on a trickle charger.
Please say something to ease the pain. Summer's coming and I can't drive my favorite car.
Last edited by Bill Krauss; Apr 6, 2022 at 09:04 PM.
Maybe this is dumb but...there have been a lot of posts about the Porsche charger self-disconnecting after a short while. That seems to be especially true for the folks who are charging via the cigarette lighter. Are you sure your charger is actually charging your battery? And I thought we established that the idea of the warranty being void if you drive less than 6k miles is horse feathers.
I charge with a connecter directly on the battery terminals. I use a CTEK lithium charger. The battery is perfectly charged. The BMS is faulty. This is the system that the car uses to regulate battery usage when the car is not running. And the fine print about the warranty is definitely out there ("lack of normal usage"). I hope it's horse feathers. I'm aware of the battery issue, but the post is more about the shortage of what I'd consider a critical component.
Limited miles because where I live snow comes up to the top of the license plate bracket for 4 months out of 12. Besides, I have a bad weather option....
I know my lithium batteries for my RC cars have to be stored at 50% charge. You can’t store them at 100% or you risk damaging the cells.
There’s also a separate cable to balance the charges in each cell. Don’t know much about the lithium battery in the 992 with RAS, but just sharing what I know.
Decent chargers pulse the battery always allowing it to drift somewhere down from 100%. This isn't a charger/charging problem. This is a faulty control module built into a super expensive somewhat "overdesigned" battery and probably the reason the battery is so expensive. I love Porsche; but, their ability to overdesign a simple component like a battery is irritating. It would have been much better to separate the management system/control module from the battery.
Last edited by Bill Krauss; Apr 6, 2022 at 09:52 PM.
I charge with a connecter directly on the battery terminals. I use a CTEK lithium charger. The battery is perfectly charged. The BMS is faulty. This is the system that the car uses to regulate battery usage when the car is not running. And the fine print about the warranty is definitely out there ("lack of normal usage"). I hope it's horse feathers. I'm aware of the battery issue, but the post is more about the shortage of what I'd consider a critical component.
There was also a long thread about how you can ruin the battery if the negative lead of the charger is connected directly to the negative battery terminal. I cried foul, but was proven wrong by a document that someone posted. (Found this link. See post 22 here): https://rennlist.com/forums/718-gts-...-tender-2.html
Your link doesn't say anything about 6,000 miles. If anything it clarifies that the battery is covered for 4 years. There is no way that they could deny the coverage based on mileage alone.
Last edited by Denny Swift; Apr 6, 2022 at 09:54 PM.
Probably a dumb question but I don't know - if the car came from the factory with lithium ion battery are you REQUIRED to use that style or can you substitute an AGM?
this warranty document is where the 6000 miles comes from. "normal vehicle use" is subject to debate. I agree with you. I'm assuming it's under warranty and the SA has said that he'll push that through. You can't substitute an AGM. again, this is more about the national shortage of batteries than battery charging practices etc. I mispoke earlier, I use alligator clips with one mounted on the ground post and one on the anode. I gave up on the using the cigarette lighter socket a long time ago. and I think the reason that's a problem is because the charge-o-mat pro lighter adapter is not designed well. i think much of the time the charge-o-mat lighter adapter doesn't seat properly in the socket, leading to a dropped connection. when i did use a lighter adapter, the ctek adapter worked fine. I just didn't like the idea of running current to the battery through a bunch of vehicle systems so i switched to using alligator clips.
Last edited by Bill Krauss; Apr 6, 2022 at 10:08 PM.
Probably a dumb question but I don't know - if the car came from the factory with lithium ion battery are you REQUIRED to use that style or can you substitute an AGM?
Unfortunately, you can’t use an AGM battery in a Porsche that came with lithium ion from the factory.
this warranty document is where the 6000 miles comes from. "normal vehicle use" is subject to debate. I agree with you. I'm assuming it's under warranty and the SA has said that he'll push that through. You can't substitute an AGM. again, this is more about the national shortage of batteries than battery charging practices etc. I mispoke earlier, I use alligator clips with one mounted on the ground post and one on the anode. I gave up on the using the cigarette lighter socket a long time ago. and I think the reason that's a problem is because the charge-o-mat pro lighter adapter is not designed well. i think much of the time the charge-o-mat lighter adapter doesn't seat properly in the socket, leading to a dropped connection. when i did use a lighter adapter, the ctek adapter worked fine. I just didn't like the idea of running current to the battery through a bunch of vehicle systems so i switched to using alligator clips.
6k miles per year is easy to identify.
But 15 miles per day? How are they going to verify that to deny a warranty claim?
So if I decide not to drive my car one day, boom! There goes the warranty? WTF.
Battery woes
