Is anyone here able to get battery tenders to work with a lithium battery in a 992?

 

I am using the CTEK Lithium US battery tender with the quick connect hooked directly to the battery in my 2023 Carrera T with lithium battery. I hooked it up the day I brought the car home since I heard all the horror stories about flat batteries in these cars, now has been a year with no issues, even after not driving the car all winter.

 

I’ve been using this all the time when not driving it! It's also hard wired to the battery. I had one from HD and it has the correct connections NOT the European connection.

 

I, too, have been driven crazy by this problem -- my 2022 Cayman S works very simply -- plug the charger in and turn it on -- but my 2024 911 T kept charging for 1/2 hour or so and then turning off. I read lots of posts, tried what they suggested, talked to my dealer's service department twice, and nothing worked.

But through a process of trial and error I figured out how to make it work using the following steps. They may as well be magic as engineering for all I know, but this is what I do and when I do it the charger stays on. The charger in question is the Porsche branded charger, but it should work the same way for a CTEK.

With the key in my pocket, I open the door, get in the car, turn the ignition key clockwise to the on position (but not to the start position). This makes the car come alive so I can lower the driver's side window an inch or two. On my car this is needed because the gap between the door and the frame is so tight that it will pinch the cord if the cord is fed through the bottom of the door and the door closed.

I then turn the ignition off, open the door, get out, feed the charger cable through the gap in the window, plug the charger cable into the 12 v accessory plug on the passenger side, and plug the charger in. At this point the charger is energized but not turned on (on my charger a green light comes on but the charger is not yet charging). I am not sure whether it makes any difference whether the charger is turned on at this point or turned on later.

I then reach in the car and turn the ignition on again, waking up the car but not starting it. If I haven't done so already I then turn the charger on by pressing the on button to select regular car battery charging (not motorcycle or lithium). I then turn the ignition off and close the door. Finis.

When I do things exactly this way the charger stays on. I have no idea why. I do NOT lock the car at the end of the process.

Regards, J.C.R.

 

I put a permanent solution in using a Magcode charging clip. The feed is only live when the charger plug is connected. It's covered and stays out of the weather. I initially had it hooked up to my NOCO but for some reason when it was fully charged it would shut off after several days of float charge. I switched to a CTEK and haven't had that problem since.

If you go this route, you do have to take a hole drill to your lower 'grill' and make sure and fuse near the battery, use conduit, etc. The benefit is it literally takes a second to hook up and if I ever forget to unplug it will simply pull the magnet off (yes, I've done that).

 

I guess I don't understand why there is a perceived reluctance to avoid using the 12V outlet in the passenger footwell vs. just hardwiring the pigtail to the battery?

 

I agree. I think the reluctance is the result of not using the correct steps and having the charger turn off after 30 minutes. Been awhile since I used the charger so I forgot the steps, but search battery tender threads and the correct procedure is mentioned many times.