matthewr87

So the servicing dealership (Porsche Silver Spring) did me a solid and disconnected this POS and ran diagnostics on the battery without charging me anything. That was much appreciated. Supposedly one of their techs used to work for the dealership across town that sold me the car and he confirmed with the service manager at Silver Spring that they installed this crap on every car they sold. So I guess that probably helped my case. Also they said the battery seemed undamaged but I'm not really sure if you can check battery health on these things? Constant excess draw can't be good for it I imagine.

kenv

Does anybody happen to know the date Porsche began building 9Y0's with the AGM battery? Are these battery problems plaguing every 2019-2021 Cayenne basic or has anyone been able to dodge the bullet? I'm wondering if it is just a matter of time before all the early cars have these problems.

wageslave

AGM in 9Y0 seems to be localized to supply issues, ie: there isn't a point in time when production cut to AGM, followed by another cut back to lithium. So it's just your luck if you got one or not.

And many have asked those with AGM to provide more info on the adapter harness, but no one has been able to provide a Porsche part number or any further solid, actionable information.

BIG8

The Service Manager at my Porsche dealer told me that converting from Lithium to AGM is not possible. FWIW, I’ve a 2019 Cayenne and no battery problems so far. I do use a battery conditioner on it about once a week and whenever it’s not going to be driven for a couple or more weeks.

LSR

My 2022 base has an AGM. I can take a look inside the battery compartment. Glad to help sort this out. What should I look for? What does the adapter harness look like?

chassis

This is believable and expected that a dealer, who is a third party agent without perfect knowledge of the matter, would say such a thing.

It is a fact that site members have posted about 9Y0.1 vehicles with AGM batteries. This establishes the fact, if the posts are reliable (I believe they are reliable), that Porsche has a "solution" for 9Y0.1 with an AGM battery.

What has not been established is how to secure the parts and coding needed to install an AGM into a 9Y0.1. Porsche or an aftermarket solution provider needs to take the next step on this.

LSR

The posts about some 9Y0.1 cars having AGMs are reliable. See photo of my car’s battery.


AGM battery in MY2022 base Cayenne.

jl1975rs

A few weeks ago I got the dreaded low battery light on my 2019 Cayenne and took it to the dealer to be checked out. The dealer told me to contact PCNA as originally they didn’t cover the battery replacement under warranty. Wrote a nice note and explained my situation to PCNA and they helped me work with he dealer. Took my car in last week and got a new battery the next day covered under CPO. They said the sensor was bad and covered that under CPO and maybe a little explanation from PCNA. I tried to push the dealer/PCNA to work with me to convert the battery from lithium to AGM, but they currently don't have an official authorized procedure. I’m happy overall and the car starts much faster in the first crank.

E'TLS

There seems to be a sudden wave of 2019 Cayenne owners reporting warning lights or issues with their OEM LiFePO4 Lithium batteries. Is 4-year the life expectancy for this type of Lithium batteries. Lead acid and AGM batteries normally last 3-5 years.

wageslave

My understanding of this is limited. The best way to figure it out would be to note the differences from the point power leaves your battery and compare that with someone who has a Lithium battery. The lithium battery has a controller that sits between the main harness/compute and the battery. Does the AGM as well? What is that part number?

And that's entirely the crux. How many other Cayenne owners does any one person know? And it's not as if you can pop into the dealership and poke around under the floor mat and try to compare your own setup with the other.

LSR

A buddy of mine up the street from me has a 2020 base. I’m going to see if we can compare what’s connected to our batteries - his lithium and my AGM. Now I’m wondering whether my AGM has any special circuitry inside like the lithiums seem to have. Everyone’s complaining about the cost of lithium replacement, but does anyone know the cost to replace an AGM in these cars? Can any AGM be used, e.g. an Interstate?

chassis

On the contrary, I pulled up the floor panel of a MY24 .2 base to confirm it has an AGM.

chassis

Yes, if it meets the “group” (size, dimensions) and CCA, etc numbers. AGM prices at MB dealers are close enough to retail parts stores that I bought from the MB dealer. It must be a loss leader for them. It would be good to know what Porsche dealers charge for an AGM. The 958 crowd would know.

BIG8

My dealer told me that these lithium batteries should last about seven years. But who knows.

pinion

On the life of LFP cells the typical ratings are 5-6000 cycles rated with 80% capacity retained.

My suspicion is that the BMS (battery management system) computer in this battery has some extremely aggressive protection/limit logic inside the software that is the source of most of these issues…

Combine that with a very active car that uses the battery power for post run cooling, always on cloud connectivity, and wide ranging environmental conditions and it is pretty easy to understand how we get to where we are.