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I got the 12v critical a few times when my battery was low, and when I was going to go charge my car, I went to the store before hand and it died on me. Being a old school guy, I have a jump pack always with me. So popped the hood and jumped the car. Everything was fine expect my main display does not work. Any thoughts on this?
 

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My understanding is as follows-

400V battery is supposed to keep the 12V battery topped up with charge as required, in almost all circumstances and even when car is off, but if it doesn't do this then the best way to try force it to charge the 12V is to charge the 400V battery as you say, or else to drive for at least 20 minutes. There is a software update for EQS from around June I think (only available at dealer) that helps reduce draining the 12V possibly either from from leaving doors open, interior lights on etc or with the keys nearby that puts the car on high alert that doors may need to be opened - I don't know the specifics.

Best option is to contact Mercedes else you could leave the car charging at a slow charger and locked overnight, with keys a good distance away just in case, and if that doesn't help then contact Mercedes. Contact them anyway to check about the 12V software update. Be interested in a report back what works for you.
 

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By the way, and others on the forum will know better than me, but following up on ways to prevent more 12V drain in future besides not letting the 400V battery get too low which I understand is what happened in your car- a third way to try force the 400V battery to keep the 12V topped up if not charging is to keep car switched on but in neutral gear and with the electric parking brake on, such as if doors will be open and interior lights on or if relaxing with climate control enabled, instead of start/stop button "accessories" mode, though again the software update may make that method unnecessary but not sure.

Also instead of keeping car away from key you can also turn off your key radio by double pressing the lock button or else simply by leaving it in a stationary position such as on desk instead of in pocket, though again I'm not sure if that makes a difference but something to experiment with if necessary.

Essentially keeping the 12V topped up is even more important than a gasoline car as the car doesn't just use it for starting the car but also I understand is used to power communication with Mercedes computer servers and for opening doors and security and monitoring 400V battery against heat stress etc. If car is unused such as at airport car park the 400V battery should keep the 12V topped up thankfully
 

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I got the 12v critical a few times when my battery was low, and when I was going to go charge my car, I went to the store before hand and it died on me. Being a old school guy, I have a jump pack always with me. So popped the hood and jumped the car. Everything was fine expect my main display does not work. Any thoughts on this?
I got the 12v critical a few times when my battery was low, and when I was going to go charge my car, I went to the store before hand and it died on me. Being a old school guy, I have a jump pack always with me. So popped the hood and jumped the car. Everything was fine expect my main display does not work. Any thoughts on this?
I bought my 2022 MB EQS 580 in late July. The next day after eating lunch out, it would not start. (I had spent a few hours the night before playing in the car trying to learn how the MBUX operates.) It was towed into the dealer & was there just over a week before I got it back. 10 days later I took it to have the windows tented. I picked it up afterwards then stopped at the bank and then it would not start once again… towed back to the dealer. This time it took over 3 weeks to “fix”. Supposedly the dealer had to constantly wait for the technicians in Germany to advise its repair. A control unit was replaced along with cables and reloaded software. Then three weeks later on the way home from work I stopped at Costco… and the car would not start again! This time I had purchased a lithium battery starter so I hooked it up to the 12 volt battery terminals under the front hood and it started up just fine. The next day I took it back to the dealer and that was a week ago, and they are still waiting to get advice again from the technicians in Germany in order to again “fix” it. I have complained to the dealer and threatened to start the Lemon Law process. It is just over 2 months old now! The dealer is talking with MB and they are deciding on buying my car back from me… waiting to here at what price. At my request they are placing an identical build order to make me a 2023 EQS 580 which I hope to receive in 4 months. I love the car and want the car, but it has to work and start without fail. I’m searching to see if this is an isolated issue or are many others having the same issue? The high voltage battery should keep the 12 volt battery charged as needed but that does not always happen obviously. I look forward to hearing comments and especially knowing if this is an on going issue. -Mark C.
 

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An update… Today my service advisor at the dealer says Mercedes is aware of this issue. So if the car does not start it should be powered off for 15 minutes to let it reboot and then it should restart. He said a software update is in the works but not yet available.
 
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