I also have the MXS 5.0. Worth every penny.

Time to own up. I have egg on my face. My mysterious battery drain puzzle has been solved after two admissions into Mercedes Salisbury. First inspection drew a blank so battery replaced. Second,presumably more intense, inspection embarrassingly revealed the problem was Nextbase front dashcam. I had assumed that switching ignition off would kill the cam. Not so. Apparently only Merc-approved dashcam will prevent this. The solution is to switch off camera at the end of the ride. All well since. Just have to devote time to understanding how the display screen and other electronic miracles work.

Since I started this thread, I wanted to provide one more update. My dealer was offering a coupon for $150 off service if I spent $300 or more. I needed a cargo liner and license plate frames for my 2020 GLE450 (ordered in July of 2019 and finally arrived in July of 2020). I decided to buy a Mercedes-branded trickle charger as part of my spend. I know it would have cost far less to buy a CTEK charger, but by using my coupon I saved some money. I also figured if I used the Mercedes trickle charger for both my 2020 GLE and 2018 AMG E43 (dealer said it would work great for either vehicle) it wouldn't void my warranties for either car. The charger works great and I've had no battery issues with either car. I keep them both locked in my garage when not in use and turn to the trickle charger if I feel my batteries might be running low. Like many of you, I'm not driving much these days. I've owned our GLE450 for 6 months and just broke the 1000 mile mark a few days ago.

Having the same problem on my E43 2018, there is no "standby" mode in vehicle settings as suggested. This may be able to be switched on by the dealer I dunno. The only thing you can do from what I can see is to turn off the interior, and tow away, alarms from the Vehicle Settings menu. Smacks as these were rushed out with a crap version of MBUX. If you do disable the two alarms you have to do this every time you want to lay up the car as they are automatically turned back on as the MBUX boots. As other folk suggest the CTEK 0.8 is an a excellent battery optimiser if you do want to lay it up.

Cheers Vin

Thanks for weighing in. My issue was solved by replacing my battery (under warranty), keeping the car locked while in my garage, and using a trickle charger whenever the car hasn’t been driven for a while.

Did locking your car help with the battery draining issue?

Yes. We now keep both of our Merced vehicles locked whenever they are not in use. My dealer strongly recommends this practice to minimize battery drain.

Thank you for sharing that.