2019 E450
Hi all! Having some issues and want to bounce some ideas.

Backstory is parked the car in the garage go out 2 days later as normal, car won’t start. Jumped it thought it was weird but okay. Car at the dealership for new tires had battery checked everything is good. 2 days Later battery is dead again, turns out it had a brake assist fault and the “camera module” was bad replaced by dealer under warranty. - dealer claims the module was causing the battery drain. Okay that’s possible. They said they checked the battery with a load test and xentry and found no issues with battery.

Once home I put the battery on the trickle charger got 100% next morning reading across the pos and neg access under hood I get 12.15V with a DMM my understanding is that it should be at or around 12.6 for full charge. But with the ECU and various systems causing drain let’s agree on 12.40V range.

at 12.15V after 10hrs I have no doubt another day and I would be having to jump it again.

The Question
Is the battery simply not holding a charge or how much parasitic drain is there on these cars? Finally if the battery technically passes a load test at the dealer how do I get them to replace the battery under warranty as part of the module issue since I’ve never had a problem before.

Thanks!

Is this the inline 6 cylinder with 48V EQ Boost?

With a 2019 still under warranty I would take it to the dealer.

It’s the V6 3.0L

I'm having the same issue with my 2018 E400C. Battery was completely dead back in October 2020, had the car transported to the dealer. Battery was declared defunct and was replaced under warranty. Shortly after that new battery started having problems with low charge; I was getting messages on the dash to "check the manual," etc. I figured it was from non-use of the car (I've been driving less than 100 miles/month since the pandemic started, as I'm working exclusively from home), so I would drive the car maybe 20 miles to recharge it. I eventually bought a trickle charger, which works great — except the battery continues to lose charge. Recently got message in red letters, all caps: STOP VEHICLE KEEP ENGINE RUNNING or something like that. Took car back to dealer last week, and their initial guess was that some module has been draining the battery. Car still there, being checked. I'll post the results when I get them. Oh, BTW, warranty has expired! Lucky me.

Man that really sucks! Especially without warranty. It’s frustrating keep me posted. I just made an appt to drop mine off tomorrow.

I can understand some Amp draw for all the electronics and without driving but there is definitely an issue here. We have a GLS that my wife drives much less than I do, similar to your situation with working from home and it has zero issues.

We have a 2019 E450 4-Matic wagon. Every couple of months we get a warning “12 V battery see owners manual,”. The car gets used every day for 25 or 30 miles and yet we get this warning. I will put it on the battery manager and hope that takes care of it. But a significant annoyance. Any free advice? Thanks.

Just my experience:

I have a 2019 E450: It only has 22,000 miles. Not much driving last year during the pandemic. I went out West skiing last week and it sat outside, with temps in the low teens, for 10 days. Came back and started with no problem. I have made 4 ski trips to Vermont with temps overnight below zero. Again no problem. In the fall and spring each year, I put a charge on the battery. So far, knock on wood, no problems with the battery.

Bottom line: what you are experiencing is not normal. Good luck with the dealer finding the fault. Keep us posted.

Exactly! I'm not optimistic that the service folks will be able to find and isolate the problem. Modern cars are laden with electronic systems, many of which could be the culprit, and I envision the dealer wanting to change out one component after another, all on my dime, until it stumbles on the answer. I fear that the only real solution may end up being a new car.

If the battery is 4 years old or more, it may be time for a new battery. These cars have so much electronics that it goes thru batteries pretty quick, the auto start stop doesnt help either.

See my earlier post — my car's current battery is four MONTHS old, an under-warranty replacement for the original battery.

In your case, it is probably a defective battery. I have read about an owner who had their key fob too close to the car when it is off which drains the battery, other than that, you might have a stray current drain on your battery when the car is off. Ask the dealer to check the amperage drain from the battery when the car is off.

Could be, but the chances of two defective batteries in a row is almost zero. As for the key fob, that's a good suggestion, but it's kept in my office a floor above and about 30 feet from the car.

A battery should hold its charge for at least 3 weeks+ in cold temperature. Chances of 2 bad battery in a row is very low but not impossible. A good tech should be able to find the cause of the drain. All they need to do is hook up an ampere meter and unplug one module at a time.

I had a similar problem with my 2019 E450 wagon in my first year of ownership. Was on a weekend trip and got a warning "12 V Battery See Operator's Manual." Later that weekend got a more ominous warning "Starter Battery Critical" with a red graphic of a close to fully discharged battery. Luckily, the car started fine the rest of the weekend but various electronics in the car stopped working while I was driving the car, including the radio and GPS. Took the car to the MB dealer when I returned home and they could not diagnose the issue so they just replaced the battery under warranty. Have not had any problems with the battery in two years since the replacement (knock on wood).

I had same issue with my 2019 e450 cabrio, never been a issue with my 2019 E450 wagon, I think there is some kind of issue with some cars.

Things going from bad to worse. My car has been in the shop at South Bay Mercedes in Torrance, CA, for over a week now. The service representative called me just now and said they have checked every electrical circuit in the car but found no problems, nothing drawing current when the car is turned off, and once again suspect it's a bad battery even though it's only four months old. He said the shop manager now wants to examine my CTEK trickle charger to make sure it's not the cause. I explained to him yet again that the problem started last fall when the car's original battery — then a little under three years old — began running down; assuming it was from lack of use, when that happened I would drive the car maybe 20 miles to charge the battery and it would be fine for a few days, and then I'd have to do it again. Eventually the battery ran down completely and the car had to be transported to the dealer to fix it; they concluded that the battery itself was bad and replaced it under warranty. I pointed out that a few weeks ago I began having the exact same problems with the new battery, and that I therefore purchased the CTEK, which had worked flawlessly — that is, the problems preexisted the CTEK and that therefore logic dictates that it CANNOT be the source of the problem. The service representative agreed but said the service manager nonetheless wants to see the trickle charger and to speak with me, so I'm taking it in tomorrow morning. I am not optimistic. Maybe I'll end up with a new car, or more likely in court. Pray for me!

CTEK is the problem: BS!

Remind the service manager that the CTEK is the manufacturer of OEM trickle charges for many manufacturers including Mercedes and Porsche

see https://www.mercedespartscenter.com/...-0009822921fp?

EXACTLY! It’s total bull****, probably an attempt to deflect responsibility and cost.

2 defective batteries in a row is highly unlikely, unless they are of the same manufacturing batch. This is possible as the 2 batteries are from the same dealer but, frankly, not likely.
As the 1st dead battery is now gone, you probably cannot find out its serial number (or whatever related info) to compare with the 2nd dead one.
It should be something in the car draining the battery.

Anyway, if it goes to court, you will win. You are ''The Judge''. Right?

Hi there, mine 220d have experienced the same issue. I'm second owner, bought it from dealer with CPO certificate and factory warranty of 9 months. Previous owner was the Dean of Rostock, Germany and the car was driven only 22 000 km for year and a half. I paid the car on Friday the 13th.. (March 2020), the day which our government declared state of emergency for Covid-19... Very bad choice...
Nevertheless, when the car arrives i had yellow message and start/stop didn't work. I took the car to dealer (before that i've done some research and the battery was primary suspected), they update the soft. Next day i took my car and everything was fine, but during first days of lockdowns i didn't drive the car very often. After 2 weeks, the problem came up again, so i call them again. This time they changed the battery. I took the car and all was green. So i drive it like this about 2-3 months, until one day in the city i was driving extra-urban and the start-stop system didn't worked again. I've checked the voltage and it was low.. I called the dealer again and with some argues and shouts they changed the battery for second time under warranty. Since then (1 year and 2 months~) there is no problem and still i don't drive the car very often but everything works fine. I've bought CTEK charger too (i don't use it often, so the battery is healthy enough without him too) , because warranty was expired and i don't want to change the battery by dealer again.

Unfortunately, in our country the dealer is only one and they do what they want, without fear of Daimler... So there are a lot of cases that mechanics in our dealer don't do the full service program. They checked the documents that they have done it, but when you made an independent investigate, some of the jobs wasn't completed. Or used the old ones parts and they say that they installed new one... Just the mechanics steal from you and Daimler. Because when your car is under warranty they change everything by book, but actually they re-install old oil, or gasket, or filter. The car is new and they relying that there will be no problem with this... It's very sadly, but we are small market for Daimler and they don't took very serious on our dealer's politics and service (that's way i bought my car from Germany directly and get serviced in Istanbul for major problems). So my guess, in order of all this is, that when i took my car to the dealer for second time and they changed the battery for first time, is that they doesn't change it really, just they re-charged it with powerful charger and on documents they said, that there was a new battery inside. And after that they send the documents to Daimler to send them new batteries, because they changed mine and on other customers, Daimler sends them X quantity of batteries, and for me have left the older re-charged battery, and dealer have extra (undocumented) batteries in storage, which after that mechanics and others sells them on secondary market. Sadly, but true...
BUT this doesn't mean that this case is like yours. May be there is a problem with batteries and there are defective parcels around the world... Mine may be the same, may be the dealer here really changed my battery two times, i can't be 100% sure, because i forgot to make some hidden marks on my first battery, for those kind of cases, so it's only a guess and i don't have any evidences.

SUCCESS! (I hope.) Picked up the car this morning. The mechanics tested all of the electrical systems but found no faults other than the battery itself, so they're convinced the problem is limited to the battery even though it was replaced under warranty in October of 2021. So they replaced the battery again — but I was not charged for either the new battery or the service! They'd also paying for a Lyft ride to pick me up and take me back to the dealership to retrieve my wife's car, which I had driven over there this morning (I drove my newly washed 2018 E400 home).

BTW, as for the new battery, it was NOT under warranty even though it was only four months old — when an item is replaced under warranty, the replacement does not get a new warranty nor does it extend the original warranty. That makes sense as otherwise the warranty could be years long.

Anyway, they agreed that if this happens again (i.e., a third time), then there's something wrong that so far hasn't been found. Hopefully that won't happen.

They also examined my CTEK charger and agreed that it's good and that I have been using it properly.

One last thing — the service representative told me that according to the mechanics, you have to drive at least 150 miles per month to keep the battery charged, which I have not been doing for the last two years.

Now a happy camper once again! Yea for South Bay MB!

Great news!

A couple of observations and things;

• About 25/30 years ago I had a Ford Mustang GT convertible that when I sold it after 4 years had less than 4,000 miles on it. The battery kept going dead and this was way, way before all the electronics we presently have. To solve the dead battery problem, I had installed a "kill switch".
• I had a 2008 Porsche Boxster that kept "eating" batteries. After the third battery, Porsche sent me a trickle charger that plugged into the cigarette lighter. That solved the problem. BTW, the charger was made by CTEK!
• Neither the Ford nor the Boxster was driven more than 1,000 miles a year. So lack of use was the problem.
• I have been going out of town to go skiing out west and my 2019 E450 sits for 8/10 days. In the fall I put a charger on the battery to prepare for the winter. Yesterday I went to the Mercedes Meconnect app and under Service starter battery it reads "Partially Charged". So I have connected my battery charger. I assume this will take care of this issue.

Warranty: Interesting about the warranty. When you have your car serviced at Mercedes, I believe all parts installed and/or used are guaranteed for 1 year.

Thanks for the info — very helpful for understanding this issue.

BTW, the charger that plugs into the car's cigarette lighter doesn't work for me — I have only one lighter, in the rear of the center console for use by backseat passengers. There are none in the front, apparently replaced by the wireless cellphone charging platform in the front center compartment and the stupid air fresher gadget in the glove compartment. The rear cigarette lighter continues to work for only 10 minutes or so after the engine is shut down. I don't know if the same is true of the front cigarette lighters.

Same with my car lighter: I have two but both turn off after 10 minutes. Presently my hood is up and the charger is connected to the " +" terminal and "-" post in the engine bay.

When they were "hot" as in my Boxster, very convenient to use: The charger was attached to my ceiling drop light in my garage: when we used the car, we unplugged the charger, hooked it on the drop light. When we returned, plugged it back it and closed the door! Presto always a fully charged battery. The battery with this system was from Auto Barn and was 7 years old when we sold the Boxster and it was 100%!

That is good news, glad you are a happy camper. Sounds to me your first battery was 3 to 4 years old with the last year of the car driven only about 1000 a year, that is a recipe for battery quick death. So while you thought it was unlikely you had two dead battery in a row, you really only had one bad battery, the first one dead from lack of use and no trickle charger.