Longroof45

No. I think I misread your orignal post.

Longroof45

I drive a '21 E450 wagon (All Terrain). I've noticed recently that after a drive of 30 minutes or so, MercedesMe will show the starter battery as "charged", as one would expect. But within as little as 30 minutes later, it will show the battery as only "partially charged". It seems that in the past, the starter battery would remain "charged" even after sitting for a few days. I wonder if it could be due to the fact that the weather has gotten colder, or whether there are varying degrees of "charged" (like really charged after a 100 miles drive or just barely charged after a 10 mile drive). If I were to drive the car again right now, it would be charged again within 20 minutes. Thoughts?

Archangel60

Thanks for this information. I have a 2023 E450 Coupe on order (in fact, today is my "Build Date" ). Bearing in mind what happens when one assumes, would it be somewhat safe to assume that this fix is incorporated into cars being built now?

rmgrenley

On this and other threads I have seen the discussions of the need to trickle charge your battery every night, etc. My ‘23 wagon build was Sept 24, but I will not accept delivery of a car that I have to trickle charge. If we can’t go on a flight somewhere on vacation and return to a functioning car 2-3 weeks later, as we can with my 2013 E350 coupe, it would be unacceptable in what will be an $80,000 car.

slk55er

You don't have to use a trickle charge every night, particularly if you are driving more than just a few miles every day. If you are leaving for 2-3 weeks, just hook up a trickle charge and leave it connected for the entire time you are gone. No problem -- the charger will throttle back and just apply enough charge to keep both the 12v and 48v batteries charged.

rmgrenley

We typically do not drive more than a few miles per day unless we are driving a couple hundred miles to our beach place every couple of months. I have owned a number of Mercedes and BMW’s over the years, and have never had an issue, even when leaving my car for a few weeks when on a long (flying) vacation. Why would I possibly want a car that I would have to worry about trickle charging when I don’t drive it for a week, or each day I only drive a few miles?
It seems like this is taking a step back. Kinda like driving cars for years and now having to worry about feeding your horse and shoveling out the **** so you can keep your buggy running. Is this the new normal???

rmgrenley

By the way, has anyone heard whether the other manufacturers who are making Mild Hybrid cars with 48v batteries are having similar issues?

Eaton

There's a new recall out for the issues.

slk55er

You probably don't. Go buy something else (while the vast majority of the 48-volt mild-hybrid vehicle owners enjoy our incredible, fuel efficient, powerful rides.)

Rbt1031

Looks like my wife’s 2021 E450 [delivered 4/2021] succumbed to hybrid battery problem as well at 7400 miles last Saturday. Roadside Assistance was also a bad experience. Tow never showed up when called on Saturday. Dealer and roadside never seemed to be on the same page. Towed to dealer Monday morning but still no one has looked at it after three days. Third time in for unscheduled repairs in a year in a half. Last two times it was in dealership for a week and looks like this time will be no different.

rmgrenley

Thank you, you have clarified the issue for me. In order to enjoy the benefits of “mild hybrid” in terms of some “mild” increase in power and mileage (mild, in relation to the benefits of a true hybrid or electric car in these regards), then I must pay the price of plugging it in frequently…unless I put a fair amount of miles on the car each day and don’t leave it uncharged while of on vacation for a couple of weeks. Oh, and I assume I have to raise the hood or the gate to hook up the 48v battery each time I pull into the garage for the day. And if one doesn’t want to do this, then they may experience a seemingly random battery failure either while out and about, or while on the freeway, and it will require a flatbed tow to a dealer and some time without one’s car.

it would be nice if this trade off was made clear to potential buyers from the outset.

Rbt1031

Mine turned out to be just a software update, but still took a week to get it back.

Rbt1031

Software update was all that was needed to fix but still took a week.

the_x167BLUES

Same same same - first it was 48v now its in for 12v - has anyone successfully had their car bought back? What is the process?? 2021 GLS towed from my garage twice. HELP!

slk55er

Keep that battery charged, particularly if you are just taking short trips. On my 2022, GLE53 I was able to access the work shop menu by pressing the home button on the cruise control side of the steering wheel and scrolling to the left. I do not know if this workshop menu is available at all times. I found the link below to be helpful if the menu is hidden.

https://m.youtube.com/watch?v=L2wFicEAWKg

To access this workshop menu, go to ignition position one, go to trip in the middle of the left-hand screen, scroll to show mileage, press, the back button and the trackpad simultaneously for five seconds, then release and press the home button, and scroll to the left, and you should see the additional workshop menu. From there, you can scroll to include vehicle data where the battery voltage conditions are shown.

I am running a test to confirm that charging the 12 V battery via the posts in the engine compartment also charges the 48 V battery. Currently the workshop menu shows the 48 V battery at 74% charge. My Schumacher charger shows the the 12 V battery at 68%. When the 12 V battery is close to 100%. I will check the status of the 48 V battery and report.

here is a link to the Schumacher charger from AutoZone that shows percent charge on the 12 V battery:

https://www.autozone.com/test-scan-a...kId=4280414646

chassis

Read about the lemon law process in your state. Specific requirements are listed before "lemoning" your vehicle. If lemoning is not applicable in your case, ask the dealer what they would offer to buy your vehicle.

slk55er

On my 2023 GLE53: Using a 12V charger on the posts in the engine compartment DOES NOT charge the 48V battery. Only with the engine running (Idle or driving) is the 48V battery charged. These are my conclusions after doing a series of tests using a 6 Amp Schumacher WiFi + Maintenance Charger from AutoZone.

Even with the ignition off, I had thought that the vehicle electronics would keep the 48V battery charged when using a trickle charger or regular charger, but that is not the case. Hereaftrer, I will use the Workshop Menu to monitor the 48V battery and insure that it is adequately charged, particularly after a series of short trips or a period of vehicle storage.

I ran a series of tests.

Test 1) In the first test, the ignition and engine were off with the Schumacher charger initially applying 6.1 Amps:

Initially: 12V at 91%, 48V at 74%
After 2 hours: 12V at 99%, 48V at 73%
After 6 hours: 12V at 99%, 48V at 72% and a Text message that the 12V battery is fully charged.

The 48V battery ACTUALLY DISCHARGED while the 12V charger was attached !!!

Test 2) After two 50 mile drives with some stop and go traffic, the 48V battery went from 76% to 82% each time.

Test 3) In a third test, the ignition and engine were off with the Schumacher charger initially applying 6.1 Amps:

Initially: 12V at 93%, 48V at 76%
After 2 hours: 12V at 94%, 48V at 73%, as DISCHARGED as before !!!

Continuing, I turned on the ignition with the engine off:

After another 2 1/2 hours: 12V at 94%, 48V at 56%, down from 73% !!!

Continuing, I started the engine idling and disconnected the 12V charger:

After only another 10 minutes: 48V at 66%, up from 56%
After another 30 minutes: 48V at 70%
After another 45 minutes: 12V at 95%, 48V at 72% and a text message that the 12V battery is fully charged.

So If you followed all of that, you will reach the same conclusion that I have — a 12V charger does not charge the 48V battery even if the ignition is on. The 48V battery is only charged with the engine running.

NOTE: There is a lot more info on this topic on the GLE53 forum here:

https://mbworld.org/forums/gle63s-gl...v-battery.html

zimirza2003

My 2020 GLS580 with 27,000 mi initially had 24V battery issue, the car would not start a few time, towed to the dealer, found out that the battery terminals were painted over at the factory.
A few times had the same issue according to the dealer the software needed to be updated. The problem gone away except in last six months occasionally the car would not start, called toll truck, however after waiting 15 minutes it started OK. This condition occured several times. Took to the dealer couple of weeks ago, they could not duplicate this condition, updated the software. I am keeping my finger crossed and hope this problem is gone for ever.
I use this vehicle to tow my Airstream Travel Trailer and always worry about getting sranded at so me remote place.

This is my 7th Mercedes and one of them I drove over 200,000 miles (deisel). I always loved this brand. Luckily my dealer, Fletcher Jones of Newport Beach, CA is one of the best dealership in US.
Also my GLS is one of the best SUV I ever had, very pleased with its performance, luxury and Emerald Green color for which I get lots of compliments
Happy traveling
CHEERS

cloudguy

Popped this issue yesterday on a 2021 GLE63s with around 27,000 miles.

Wouldnt start - screen said 12v battery malfunction. Overnight the 12v battery low charge warning came in and then while it was being towed to the dealer it kept coming back repeatedly as low charge. So something is draining the battery. Ironically I just got the bulletin in the mail about bringing the car in for a software update for the 48v BMS. Maybe it’s just a software thing - but last year I was having issues with the battery cooling system causing a CEL. So the battery might be fried - it was up around 90 degrees yesterday so the first super hot day of the year.

mbsea

This issue is far from resolved. My 2021 All Terrain failed first at 6k miles and again this week at 23k miles. Both cases - 48v battery failure. The dealership remains clueless, the battery supply chain continues to be ridiculous with weeks delay in securing a new one, but to the service tech’s credit, they’ve gotten a lot faster about diagnosing the problem.

I think I’d rather drive around with a live hand grenade in the backseat than with a battery that could crap out on me at any time. I will forever live in fear of being stranded in the middle of nowhere, 500 miles from a dealership. As such, sadly, I will likely move away from Mercedes when my lease ends in January.

Unless there’s some clarity from
MB about the cause of this (and correction), I simply don’t see the logic of living with the constant risk of such catastrophic failure. It’s really sad, because I love the car.

if I could go to AutoZone and just buy a new battery, I might feel differently, but this is a $3000 piece of specialized equipment, and nobody deserves to have that kind of liability hanging over their head for as long as they own their car. This must be costing Mercedes-Benz of fortune.

ettezils

I just had this happen to me & completely disappointed & overwhelmed. I haven’t even had my car for 6 months yet, 2020 CLS450…got it as a pre certified with 8k miles. It’s Saturday night & no dealer is open tomorrow morning, lucky it turned on & I was able to drive home but the engine light remained on. Does anyone know if the this is all under warranty? I bought a new car to avoid car problems & now this!

RA040624

Hi all, yes this issue with the car not being able to start has happened to me on December 6th and all the warning messages came up on the screen and was unable to start the car and it had to be towed to the dealership.
Dealership said they did a ignition software upgrade and it has been running fine until today, December 25th. Went to start the car and all the warning messages popped up again and unable to start the car. My Mercedes app received a message saying 12 volt is critically low. I took my volt meter and I tested the battery. It was well over 12 volts and all systems on the car meaning the hatch the radio lights. Everything works. It just won't start, and it does not even turn over just dead!. But I am taking it to the dealership tomorrow. Any lemon law class action suits starting on this yet. Because I have lost all my faith in any long distance drives. And speaking of driving it long distance. I did put 60 mi on the car Christmas Eve. Only to have my Mercedes app say my 12 volt battery is critically low. Thanks for any advice in advance

e55phil

Sorry this happened to you!

ever7383

Hmmm I guess to simply put it, basically all cars with the M256 with the 48V mild hybrid system.

RA040624

Not sure what you're saying here, if that is a question.
Mine is a 254x engine. GLC 300 2.0 l turbo.