Schnave

Great news! And yes, your e-Hybrid has an alternator — it’s just not mounted on the engine as in ICE vehicles. Your traction motor is normally driven by the HV battery. It is located in the transmission in place of the torque converter. But when the engine or regenerative braking drives the motor, it switches to alternator mode and charges the HV battery. A DC/DC converter is used to charge the 12V battery.

That same traction motor is also what starts your engine. It does triple-duty: traction motor, alternator, and starter.

Lphiesmacks10

So our 12V battery died again this past weekend. We left it locked and plugged into the Porsche Mobile Charger Connect from about Friday evening till Saturday evening. I am wondering if maybe something about leaving the charger plugged in after charging is complete might be draining the 12V battery somehow. This is just based on what happened last time, except I had the car unlocked. I'm going to test again this weekend with unplugging the car after charging is complete to see if the 12V battery dies after 24hours without being left on the charger.

I had an appointment with the dealer yesterday to change out a tire and they did a diagnosis on the 12V battery and came back with nothing. I do have another appointment scheduled on March 7th with a loaner, so they will have more time with the car to diagnose.

normp

Something is certainly not right here- vehicle sits for about 24 hours and is DOA, it shouldn’t matter if it’s plugged in or not, locked or not. It will be interesting to see what the dealer finds when you’re able to get in there.

My ‘19 e hybrid sits on the charger, in the garage, unlocked, for as long as 2-3 weeks without any problem, probably jinxed it now, dang.

Lphiesmacks10

Yeah, I'm still troubleshooting myself until our appointment next Monday. We haven't had any issues since the last time it died. I've been using the departure timer to charge and take the plug off after charging. Also been disconnecting the dashcam after driving. The outlet does turn itself off after 30min if I leave it plugged in, but I wonder if it still has a parasitic draw.
I'm curious if maybe my wife or I had left the My Porsche app open in the background on our phones. I've read that that might keep the car awake if left open.

Schnave

First mention of the dashcam. That would be my prime suspect. Was the dashcam plugged in when the battery died? And now that you unplug it you’ve had no problems? Hmm . . . Still, I wonder why the DC/DC trickle charger couldn’t keep up with the dashcam’s current draw. Curious what the trickle charge profile looks like.

Lphiesmacks10

That's what I can't remember. But prior to all this trouble, I would leave a CTEK trickle charger on with the car unlocked and the dashcam plugged in with no issues. We drove it a lot this weekend, so I wasn't able to test leaving the car undriven for an extended period of time.

Do you have comfort access? One thing I've noticed is that leaving the car locked overnight, the comfort access will be shutoff the next morning. I have to open with the key fob, which is no big deal, but I wouldn't expect the comfort access to be shutoff only after several hours. Just something else that makes me wonder if the 12V battery is being drained. I think I should test by locking the car, connecting the CTEK overnight, and see if comfort access is active in the morning.

Miggytosh

Hmmm…. Sounds like something is definitely up with your Cayenne or 12V battery. I have a ‘19 e-hybrid and after recently leaving it for over a week with it plugged in to the hybrid battery charger but without a trickle charger on the 12V battery I had zero issues with the first start afterwards. Original 12V battery and Comfort Access/locked. Also had Garmin dash camera and chi charger for my phone, all wired and live.

Schnave

Sorry to resurrect an old thread but I just found good info and remembered this post.

Your eHybrid has an emergency release for the charge plug:.

• Access through the fuse panel located on left side of cargo area.
• Pull the blue emergency release lever.
• The red lever is used to manually unlock the charge port door.

Lphiesmacks10

Thanks for this! Very helpful!

Good news is we haven't had any trouble with the 12V battery dying for awhile.