Have an AMG EQS on order with production in July and installing the ChargePoint in my garage. There are times during the year where I will not drive the EQS for probably 2-months or more, during the winter when I use my G63. How long can the EQS sit and hold an adequate charge or, can I simply leave the charger plugged in to maintain the batteries at some lower level for an extended period?

 

Dont leave it plugged in. The procedure is to charge to 50. Lock the car and thats it. I haven't read a straight answer how long that would last but I believe it multiple weeks. Multiple mths I have no clue. Maybe a 12V battery tender for the 12V battery might be a good idea in that situation.

 

The recommendation from MB was indeed to unplug the car and check every 6 weeks. If battery is 30% or below plug it in and charge back to 50%. But as you might not be in the same location as the car, another member suggested it made more sense to leave it plugged up and manage the review and recharging with the App. The car is "supposed to" maintain the 12V but I would feel much more comfortable with a battery maintainer.

 

I suggest that you drive it to North Carolina and I will be happy to "car sit" for you during the months you are going to drive it. I will even exercise it daily so it remains happy! Let me know when you are coming

 

You would not believe the number of "fiends" that have volunteered to car-sit for us while we are traveling next week. They are just sooo nice.

 

It's hard not to love an Old Dawg...especially one with an AMG

 

I asked the MB foreman this same question and he said there should be no need for the slow charge trickler. As long as the hood is closed, the 12V battery will be charged.

 

Has that changed? From other posts on the forum I've understood that the 12 V battery is only charged when "the engine is on", not when the car is parked.

 

Lets get it straight.....I was the one that suggested the trckle chager and I was wrong.
The recomended long term storage is charge to 50. Unplug the vehicle and thats it. No trickle charger.

 

So either way you are wrong (also right). I know the manual recommends the actions you describe above. The manual also says:


Why does the vehicle need to be switched on when the 12 V battery is low? I interpret the 12 V battery may die irrespectively of the high voltage battery having enough juice. The solution is to drive the car (which mainly consumes the high voltage battery further but also enables 12 V battery charging). The second option is a bit unclear, isn't any high voltage battery charging sufficient (at home or at a charging station)?

On the other hand, the high voltage battery has no load when the car is parked. The 12 V battery keeps many systems up and running. Odd if the advice is to only follow up the high voltage battery voltage during long term parking unless the car actually charges the 12 V battery when needed (thus the only concern being the high voltage battery running out). I'd like to see the function description from the workshop documents if anyone has that at reach.

 

When my car was at the shop for PPF and tinting, I got the notice via the app that the 12V battery was critical. Contacted the dealership and was told that because the hood was opened, no changing was done. Sure enough, after they closed the hood, everything went back to normal.
Initially, I was concerned about the well-known PTCU update, and it turned out this update is VIN specific and I didn't need it.