GT/C192/R192: GT low battery
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Joined: Feb 2026
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AMG GT55
GT low battery
In the middle of snow storm currently, and I checked my mercedes app and it says "very low battery". FWIW the car has like 300 miles did like maybe 250 miles in the past 2 weeks I've had it. Is this normal? I left my 2019 M850i coupe for a month in cold temperatures and didn't get that warning ever. I just drove circles in my condo garage to charge it up a bit and the warning on the app is gone.
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AMG GT55
Did you ever go to the dealership about this? Or is this the only solution to leave it charging every few days?
My condo doesn’t really have outlets in the garage at least in my spot
Last edited by chancellor; Feb 24, 2026 at 12:12 AM.
Junior Member
Joined: Oct 2018
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From: Maryland USA
2024 GT 55
This is a known problem with our cars as well as the R192 SLs. As Vic55 said, hooking up to the trickle charger in cold weather is the best solution. It also helps to turn off the smart key if it is in close proximity to the car, as the car will continuously search for it, burning battery along the way. There are several other threads on this forum about this problem, so try the search function for "battery" to get some further feedback/suggestions.
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Newbie
Joined: Feb 2026
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AMG GT55
This is a known problem with our cars as well as the R192 SLs. As Vic55 said, hooking up to the trickle charger in cold weather is the best solution. It also helps to turn off the smart key if it is in close proximity to the car, as the car will continuously search for it, burning battery along the way. There are several other threads on this forum about this problem, so try the search function for "battery" to get some further feedback/suggestions.
it seems like some have had software updates? Did you notice any changes in your GT
Member
Joined: Sep 2018
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24 AMG GT55
I daily drive mine and still frequently get those battery messages. It has to be because of all the digital extras constantly using it in the background. I get the rain monitoring messages almost daily. Has anyone tried swapping in an aftermarket battery? Wondering if that would make any difference.
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Joined: Nov 2001
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From: THE Orange County, California
2024 C8 Z06- 2025 BMW CS- 2022 Porsche 992 GTS
I havent driven the car in a week exactly and I just got the stupid app warning (low 12v battery blah blah) so I plugged it in earlier today and its all good now. But it will come back no matter what.
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From: Suburban Maryland
2023 E 450 Sedan. 2018 GLC 300. 2013 E 350 Coupe (retired)
Not sure if this will last long enough to fully charge your battery.. Plug your charger in when you don't have an outlet.. Better than nothing. Isn't that the Mercedes motto?
https://www.walmart.com/ip/OUPES-Exo...me/15466552099
https://www.walmart.com/ip/OUPES-Exo...me/15466552099
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AMG GT55
Let us know how it goes! My car is getting some color PPF done, so will probably visit the dealership in 1.5 weeks or so
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2025 AMG GT 55; 2022 e53 coupe: 2019 e450 coupe
I advise you to tell your ppf installers to hook up the battery tender when you are getting your work done. My battery died during my installation and I had to manually unlock and pry the handle open for the door.
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From: Rome, Italy
AMG GTR 2021 (Euro version)
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AMG GT55
When I took mine in for it's first service a month ago they replaced my battery under warranty. They said it wasn't holding a charge. I too often received low battery warnings.
I advise you to tell your ppf installers to hook up the battery tender when you are getting your work done. My battery died during my installation and I had to manually unlock and pry the handle open for the door.
I advise you to tell your ppf installers to hook up the battery tender when you are getting your work done. My battery died during my installation and I had to manually unlock and pry the handle open for the door.
did the new battery end up fixing things for you?
I also drove like 2-3 hours before drop off haha
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2025 AMG GT 55; 2022 e53 coupe: 2019 e450 coupe
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Battery Stuff
The 2024/ 2025/ 2026 Mercedes-AMG GT 55 and 63 utilize a dual-battery system to manage its high electrical demands.
The system consists of two distinct units:
The car's onboard computer (MBUX) typically uses distinct messages for each battery:
In most modern Mercedes-AMG models of this generation, the "auxiliary battery" is actually a solid-state voltage converter (capacitor) rather than a traditional lead-acid battery.
The system consists of two distinct units:
- Main Starter Battery: This is the primary battery (often a heavy-duty AGM unit) responsible for providing the high cold-cranking amps needed to start the handcrafted 4.0L V8 Biturbo engine.
- Auxiliary/Accessory Battery: A smaller secondary battery that powers the vehicle's complex electronics, such as the MBUX infotainment system, ambient lighting, and active safety sensors, while the engine is off or under heavy load. This setup prevents these "gizmos" from draining the starter battery, ensuring the car can always turn over.
The car's onboard computer (MBUX) typically uses distinct messages for each battery:
- Main Starter Battery (12V/48V):
- The Warning: Usually says "12V Battery: See Owner's Manual" or "Stop Vehicle: Charge Battery".
- What it means: The primary battery that starts your engine and powers most high-load systems is low. This is often caused by leaving lights on, short trips where the alternator can't recharge it, or simple old age.
- The Risk: If you ignore this, the car might not start the next time you turn it off.
- Auxiliary Battery / Voltage Converter:
- The Warning: Typically displays as "Auxiliary Battery Malfunction".
- What it means: This smaller backup unit (often a capacitor or small battery) is failing. It supports sensitive electronics like the gear selector, start-stop system, and safety sensors.
- The Risk: The car will usually still drive and start fine, but your Eco Start-Stop might stop working, and certain electronic "comfort" features might behave strangely.
- The "Secret" Menu: You can often view the exact real-time voltage of your batteries through the "Workshop" menu on your digital instrument cluster. A healthy battery should sit around 12.6V with the engine off and jump to 14V+ once the engine is running and the alternator kicks in.
- Battery Tenders: If you don't drive your AMG GT 55/63 daily, it is highly recommended to use a Mercedes-Benz Battery Trickle Charger to keep both systems topped off and avoid these warnings.
- Access: To reach it, you usually need to lift the trunk floor panel (the luggage area floor). It is often housed in a dedicated compartment toward the center or right side to help balance the weight of the front-mounted V8 engine.
- Jump-Starting: Even though the battery is in the back, you do not have to access it to jump-start or charge the car. There are dedicated remote jump-start terminals under the hood:
- Positive (+): Look for a red sliding plastic cover near the firewall or passenger-side strut tower.
- Negative (-): A dedicated brass or silver grounding pin/nut is located nearby on the vehicle frame.
In most modern Mercedes-AMG models of this generation, the "auxiliary battery" is actually a solid-state voltage converter (capacitor) rather than a traditional lead-acid battery.
- Access: It is typically located in the passenger-side footwell.
- How to reach it: You would need to pull back the floor mat and the carpet panel under the dashboard/glovebox area to find the unit tucked behind a plastic cover or bracket.
Junior Member
Joined: Oct 2018
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From: Maryland USA
2024 GT 55
If it got a software update, it only marginally helped with the problem. Extreme cold temperatures still result in the "12v battery extremely low" error message in the app if i don't keep it on the charger.
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AMG GT55
Will record how many days it lasts after a long drive the day before I arrive
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AMG GT55
just came back from the dealership after my color ppf. They are saying there’s no issues with it and no available updates. But I feel like this can’t be. I’m going to Japan for 10 days this weekend so will see if the car starts up. I have a jumpstarter so will see.
Will record how many days it lasts after a long drive the day before I arrive
Will record how many days it lasts after a long drive the day before I arrive
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From: THE Orange County, California
2024 C8 Z06- 2025 BMW CS- 2022 Porsche 992 GTS
Edit--- found this on Ai
To activate battery-saving "Standby Mode" in a Mercedes-Benz (often for long-term parking), turn the ignition to accessory mode (press start twice without touching the brake). Navigate to Settings > Vehicle > Other Functions and select Activate Standby Mode.
Last edited by Vic55; Mar 16, 2026 at 02:44 PM.
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2025 AMG GT 55; 2022 e53 coupe: 2019 e450 coupe
My experience with that function is that activating it and the subsequent deactivation will reset some of your preferences like welcome light preferences and some other customizations.
Once activated you will need to hit unlock on the key fob to wake up the car. Door handles will not open otherwise
Once activated you will need to hit unlock on the key fob to wake up the car. Door handles will not open otherwise
Junior Member
Joined: Oct 2018
Posts: 55
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From: Maryland USA
2024 GT 55
My experience with that function is that activating it and the subsequent deactivation will reset some of your preferences like welcome light preferences and some other customizations.
Once activated you will need to hit unlock on the key fob to wake up the car. Door handles will not open otherwise
Once activated you will need to hit unlock on the key fob to wake up the car. Door handles will not open otherwise
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From: Costco
2023 S500
Just curious for those with battery issues: do you keep auto start/stop on while driving? I know this can drain batteries. It’s not too bad on cars with the 48V mild hybrid, but I imagine it’s probably brutal on these cars.
I also place my key in a faraday pouch as the car will sometimes not fully go to sleep if it senses the key nearby, or so I’ve been told on the S Class forum.
I also place my key in a faraday pouch as the car will sometimes not fully go to sleep if it senses the key nearby, or so I’ve been told on the S Class forum.
