48 Volt battery problem? Check in here.




If you have been impacted by this problem please post to this forum. Whatever type of Mercedes you drive please post. This way we can begin to get an idea of how many people are having this problem.
Is it the exception to the rule or the rule?
MY:2021
Issue: 48v Batter Failure (error on screen was actually a 12v system failure)
Mileage at Failure: <50 miles (brand new car)
Fix: New 48v battery installed; no other work mentioned on service receipt
Current Status: Working at 152 miles on the odometer
As of today there don’t seem to be many reports from S-, C-, or GLA-/GLB-/GLC- Class owners.
Last edited by chassis; Nov 17, 2021 at 06:53 AM.




If you have been impacted by this problem please post to this forum. Whatever type of Mercedes you drive please post. This way we can begin to get an idea of how many people are having this problem.
Is it the exception to the rule or the rule?
My car is a 2021 E 450 All Terrain with approximately 6,700 miles, delivery taken at the end of March 2021. It would not start 5 days ago while parked in the garage and had to be flatbed towed to the dealer. (BTW....the MB Roadside assistance is great up until you need it. I waited over 11 hours for my car to be successfully extracted from the garage and hauled away.) As of today my car has been with dealer for 5 days and other than confirming it would not start due to a faulty 48v battery, I have received zero support from the dealer. I am without a car (no loaners are "available") and they have given me no information on how long my car will be out of service. I can't even get them to confirm that Mercedes has authorized a battery replacement.
Dealer insists this is an extremely rare occurrence, and that they don't stock 48v batteries because they are lithium and they don't hold a charge in storage. Based on this forum, I am having a hard time believing that this is a rare occurrence.
Other than that....crickets. Very disappointed in both Mercedes Benz and the dealer. They can do a lot better than this.




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I feel your pain.
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If you have been impacted by this problem please post to this forum. Whatever type of Mercedes you drive please post. This way we can begin to get an idea of how many people are having this problem.
Is it the exception to the rule or the rule?




I'm not sure what display of battery/charging is incorporated into the latest MBUX. On my '19 CLS53 (no MBUX) this display is accessed by selecting "Vehicle" and then "Consumption". The green bars show "Charge %" which is NOT the amount of charge on the the Lithium battery. It is the percent of charging BEING APPLIED by the MGU to the batteries. I complained to MBUSA that we need a display of the charge level of the battery such as is provided to the EVs, but no such luck. Maybe with MBUX try saying "Hey, Mercedes, what is the charge level on my batteries?"
Two samples of this display are attached below. The first is typical of "normal" driving where the "Charge %", the amount of charging being supplied is 5-10% of the maximum output of the MGU over a 30 minute period (you can select 60 minutes also). The second image was taken during the long, 15 mile descent into Denver from the mountains where the charge occasionally reaches near 100%. If your system is operating normally, you should see displays like this and if you become familiar with how this display looks under various driving conditions, you might be able to detect an impending problem. Let us know if you see anything anomalous.




My car failed twice in 60 days. I received this error a second time, 1000 miles after the first failure. My car was there a week they told me that the engineering personnel determined that this is a software problem updated my software. I'm crossing my fingers that the problem has been resolved.
I have no knowledge of battery technology but it is logical that it is a software problem because it seems to me that by now battery manufacturers have their act together.
It is a shame that MB seems to not care.
I've reported my failures to the NHTSA as suggested by other members of this forum. The hope is that if enough owners report their battery failures as a safety issue, maybe it will encourage MB to be more proactive.
Add in the rattle/squeak interior and I wish I had just gone with something else at this point.
I wouldn't count the car out quite yet. I know this sounds like "Other than that, Mrs. Lincoln, how did you enjoy the play?", but I have the E450 wagon and, aside from that little old battery thing (wink wink), I actually love the car. I love the powertrain and I love the tech. It's a great ride. However, like Phil, who commented above, I also had two failures, the first one at under 200 miles and the second at under 1,000. In my case they actually replaced the 48 volt twice and updated the software, and I'm still going strong 3,000 miles later and enjoying every minute of it. One problem, of course, is that it shatters your confidence in the reliability of the car, so you keep waiting for the other shoe to drop. And of course the overriding problem is MB's apparent refusal to address issue with a recall or at least a statement that they've identified the problem. Instead, we're all left to get our information on a case by case basis from the various dealers (and the dealer responses aren't always consistent), and from the exchange of information on this forum.
The good news is that, other than Phil and me (I think we were both 3/21 build dates), I don't think there have been any other reports of repeated failures once the 48 volt has been replaced and the software updated. So, hopefully, you'll be "one and done" have and have miles of good driving ahead of you. Fingers crossed.
Last edited by Longroof45; Dec 6, 2021 at 11:44 AM.
















