2017 S500 Coupe has problems starting .

[TRAMPAS1234]

When it has not been used for a while, the car is reluctant to start. Is there so much going on "in the background" that the battery is gradually becoming flat?

 

[Blobcat]

Hello and welcome,

Modern cars don't like sitting around to long. There's way too much electrickery involved.

Healthy battery should be ~12.6V with ignition off and ~14.4V with engine running

 

[Craiglxviii]

When it has not been used for a while, the car is reluctant to start. Is there so much going on "in the background" that the battery is gradually becoming flat?

Yes. A LOT, these cars can run a 0.2- 0.3A current drain when shut off and locked.

My 215 will last maybe 10 days of no driving and very cold weather before it struggles to turn over and needs to be put on charge.

Tbh I just leave the charger in the boot now.

 

[TRAMPAS1234]

As the car is in a locked garage would leaving the car unlocked save a bit of battery drain? With cars lying unused during the pandemic this must be a general problem these days.

 

[Craiglxviii]

As the car is in a locked garage would leaving the car unlocked save a bit of battery drain? With cars lying unused during the pandemic this must be a general problem these days.

No. Leaving it unlocked will make the current drain worse, not better.

 

[mioba]

When it has not been used for a while, the car is reluctant to start. Is there so much going on "in the background" that the battery is gradually becoming flat?

Yes.

even my W220 struggles after 8 days sitting.

 

[Wighty]

Call Mobilio buddy ?

 

[bembo449]

sell the car to me for 10k , problem solved lol