runbuh

I have a 75A PowerMax 12V external power supply that I use when I'm coding via PIWIS. That same power supply does a great job of resetting the battery. One time, the battery would not "stay" reset, even though it appeared to have a good charge. As soon as I shut off external power, it would disconnect itself. I had to use PIWIS to clear some errors on the car before the battery would stay connected (ran PIWIS with the external power attached.

I can tell you for sure that no low amperage Ctek or NOCO 5 is going to be able to reset the battery. I tried the special modes on both chargers. Spend the $ and get the PowerMax, make sure it comes with the cables/clamps (some people only sell the power supply itself). They're not cheap, but it beats waiting on the tow truck. Now, if you have another car in the garage, just hook up some jumper cables...

ThaiGuy

Thank you! So by hooking up jumper cables from another car (which has lead-acid battery) will 'reset' the lithium battery on Cayenne? My car can still start fine, but it has that annoying warning light and noise when starting.

rjk25

I have same issue, yellow warning on dash when started... but runs fine I'm not sure if I should take to dealer or is there something I can do to reset it.

ThaiGuy

One difference I noticed between pre-yellow light and yellow-light is how the voltage is read on the dash. Before I got the light, when driving, voltage went up and down between 12.9v and 14v and now, with the warning on, it pretty much stays quite steady at 13.5 +- 0.1. I am not a car tech guy and not sure what this difference implies.

PorscheACC

I wonder if it is a BMS software charging issue that happens somehow..

Personally, I would first reset the BMS charging state of the battery, by re-registring the battery. You can just replace a digit from the serial number.

The outcome may be a different charging pattern, as if it was a new battery, or the same, if the issue is with the internal controller/sensor in these highly defective LG Chem company batteries..

enzowhatever

Hello Everyone,

I received my module about two weeks ago, but I was lazy since my lithium battery is still working. Until three days ago my Cayenne is completely dead, not even jumpable and the lithium battery is open circuit. I guess this almost 5-year old LG chem battery finally gave up (seems like the quality is okay with this one). So I went to Costco bought the H8 group battery and did the conversion. After the installation, I used the supplied OBD device to flash the car, which I have no idea what happened, but it only took three minutes. I have an iCarsoft, and I didn't see any fault code related to the battery. The overall cost for replacing the battery is around 500bucks (battery 200, 300 something for the module).

The module is mounted on the original negative terminal of the frame and the negative terminal cable is in series with the module and the battery negative terminal.


The conversion is done.

The module connects to one of the unused positive terminals on the positive cable and you just need to hook up the LIN cable.

enzowhatever

The only disadvantage I noticed is that the Start/Stop cannot last as long as the lithium. The battery quickly dropped to 12.3V ish when the start/stop worked, but this is the nature of the AGM, it cannot hold the high voltage like the lithium. Overall I am happy

George718

My question is how much longer for a class action or even better for Porsche to bite the bullet and issue a costly recall

PorscheACC

Congratulations.!! Great find and solution..

Can you post the website where can buy this device?

What kind of OBDII device and software medium did you use to flash the vehicle?

How did they send you the software patch to apply it?

I have my Start/Stop disabled years ago. Best thing I ever did on my Cayenne S..

enzowhatever

I am a Chinese, so I found some people on Chinese TikTok when I saw somebody on the forum mentioned some Chinese guys managed to bypass the thing, initially I thought it was sketchy, but I found those people actually have done with like hundreds of those conversion. I also found found a guy did the wireless full screen carplay update for me, mine is a 2019, those guys can do a lot of things.
I think the OBDII device is 800CNY, the module is 1500CNY ish. And you can use the OBDII gadget repeatedly to flash as many as cars you want. The OBD2 device is ridiculously simple, just a OBD2 port with a USB port, and I just plug the flash drive thing on the OBD2, then plug into the car.
I will ask the seller if he wanted to do internationally business.
BTW, how to disabled the START/STOP?

There is a flash drive thing came with this OBD2 thing, and you need to charge the flash drive with type C cable while flashing. I have no idea what happened, but it was quick.

PorscheACC

What state in the US are you in..

It will be great to have that guy in China expand his bussiness internationally. There are so many screwed Porsche owners here in the US with that $2,200 battery plus $1,000 installation charges by dealers.

Below is a post where I explained how to didable the Auto/Start/Stop using an Autel device.

I really don't like the Autel company, since I found that they disable all online features in addition to the software updates if you don't pay for a software subscription every year.

Autel charges half the value of the $1,000+ device for software subscription.

Autel deceptively only advertises that they will only stop software updates, but again in reality, your $1,000+ device Coding, ECU, etc. online features become disabled without a software subscription and practically useless.

Thanks for all yiur information.. It's great..


https://rennlist.com/forums/cayenne-...l#post17826024

enzowhatever

I'm in Madison,Wisconsin. If you are close, you can stop by and I will explain in detail and maybe borrow the OBD2 thing to you later.

PorscheACC

It's about 1,143 miles from where I live in Texas..

Too bad that we are in a tought winter right now, too.. Although, Texas freezing winters here only last a couple of days..

But, maybe I'll take your offer and fly with my wife to Madison some time later, and go get a coffee or dinner and talk about it.. We have not been in Wisconsin yet.. Perfect opportunity to visit Wisconsin..

chassis

@enzowhatever Thanks for your posts. Unfortunately the photos do not show the device entirely installed. The photos do not show necessary information.

The product module is connected to the battery negative post. What precisely is this module doing? What is its function?

The product positive wire connects to the battery positive post.

The product LIN connector connects to the vehicle-side LIN connector.

What is the purpose of the ODB device? Why is it included in the product?

As can be seen below in a MY24 .2 Cayenne, the vehicle-side LIN connector attaches to the battery negative post. This photo was first posted in this thread in July 2023.

I hold the view that a MY24 .2 negative cable would facilitate a .1 Cayenne originally built with a LiFePO4 battery to use an AGM. It's a several hundred dollar investment to potentially save $2,000 per battery replacement. It would also likely void the warranty, for any vehicles that are covered under warranty.

RG928

Is there a temperature restriction on keeping these batteries on maintainer? We are in a cold snap and it’s been on the maintainer for days but temps are supposed to get to 0 or below. Just wondering… it’s in the garage but still pretty cold.