I replaced my original battery after nearly 6 years with an AC Delco group 49 battery with 900 CCA and 170 minutes of reserve capacity (even though the Walmart site said 160 min of reserve capacity). Battery replacement is usually an easy task but because the new and old batteries weigh a lot (nearly 60 lbs for and H8 or group 49 battery) and the tight location of the battery, it took me around an hour. I didn't have to do anything in preparation. I didn't need a 9 volt battery to back up any memory items. There are a few things to keep in mind:

1. The battery is located under the dust filter on the passenger side of the engine compartment.

2. Since you'll have to remove the dust filter assembly to get at the battery, this would be a good time to replace that (I bought a new one, Mahle part no.LA 877).

3. You'll need a Torx bit socket set to remove the old battery and to clamp down the new battery. IF YOU DON'T HAVE A TORX BIT SOCKET SET, DON'T ATTEMPT THIS. Normally, manufacturers use a 10mm hex bolt, but for some reason, Mercedes decided to use a Torx bolt. You'll need a Torx bit

set and at least a 6" extension. I put two 6" extensions together as shown in the attached photo.

4. It's best to put a "cap" over the negative and positive terminals after you loosen the 10mm nuts that hold the leads to the battery. My new battery came with these caps so I just took them off the new battery and put them on the old battery.

5. Make sure you remove the vent tube from the old battery and tape it to the body so it's out of the way and ready to insert into the new battery.

6. Tape down the negative and positive cables out of the way or have a helper get them out of the way when you remove the old battery and install the new battery.

7. My battery (and all the AGM batteries I've seen) have holes on the negative side and on the positive side. If your new battery didn't come with a plug for the positive side, you can remove the one from your old battery and insert it on the positive side before you install the new battery. Leave the hole on the negative side empty as you'll be inserting the original vent tube in there.

8. The hardest part is getting the new battery in the tight battery compartment and clearing the negative and positive cables. This is easier if you have a helper.

9. You should remove the positive cap and connect the positive cables first, while the negative cable is still disconnected.

10. Once you're sure that the negative cable will reach the negative terminal of the battery, you can connect the negative cable after you remove the cap that you put over the negative terminal earlier. At this point, the electrical system is live, so you should be careful not touch the positive terminal at the same time as any metal parts of the car or the negative terminal of the battery.

 

Great DIY. You don’t need a torx bit for the battery hold down, a 13mm socket actually works better. I just did mine today.

 

Great Post! Many thanks.

Because of the position of the battery, its weight and mainly my advanced age, when I need to replace mine I have decided to have having Walmart do it. I took delivery of my E450 in December 2018 so my battery like yours is entering its 6th year.

I noticed your post about ordering the H8 from Walmart and on the anticipated day of arrival it failed to show.

What I plan to do is order both the H6 and H8 from Walmart. When either or both arrive make an appointment for installation - no charge.

If the H8 arrives I will have it installed and while waiting for the installation, return the H6. If only the H6 arrives have that installed.

While the H6 has less of a reserve, 760 vs. 900, for my needs the 760 will be more than sufficient.

Just my $.02 and again many thanks for the great post! Much appreciated.

 

That's good to know and to point out. Luckily I had a torx bit set but I guess I would have tried using a socket if I didn't. There are a few traps for the unwary when doing this. For example, how many mechanics would think to plug up the unused vent hole on the battery? That reminds me of the time that I had the Jaguar dealer replace my battery under warranty, and when I got home and checked, I couldn't see the vent tube at all. So I call my service advisor and told him that the vent tube was missing. His response was "What's a vent tube?" Obviously this guy had never seen a battery in a European car. I later found the vent tube in the back of the battery (which was in the trunk) and inserted into the battery myself.

 

Does the H8 fit for my 2019 E450 Wagon? When I look online for fitment with Walmart, Autozone, etc, they do not show anything available?

 

I believe there is stay that can be removed and when it is removed the H8 will fit.

 

It’s crazy no places around here will do my battery. I think I’ll just have the dealer do it. Anyone know around what the cost was having the dealer do it with a Mercedes battery? Probably around 500 I can imagine.

 

What about Walmart.

I think $500 from Mercedes is in the ball park.

 

That kinda gets me a little bit nervous bringing a nice car like mine to Walmart. I've had experience like things being done really sloppy by some places in the past and a overall better experience with things being done neatly and no grease on the floor mats ect with the dealer. I did make a good find yesterday that it's worth it for me travel to the Tampa area for MB service as it's less money than in Mid southwest Florida and less of a wait to get an appointment there are not enough Benz dealers in the Sarasota area. I'll probably take the car down that way soon to play some tennis with a friend that lives down there and drop the car at the dealer to get a service A and the battery changed out. I put the battery on the charger for now and I'll see how that works out tomorrow. The car had sat mostly the past couple of weeks that could be why I was getting the "Stop driving/leave car running message" on the display. Seemed like the car cranks over fine. These cars are real finicky about the voltage they are getting from the battery.

 

As James Carville put it: "It's a battery!"

Actually I think Walmart will do a better job: They do tires, batteries and other simply jobs: There is nothing esoteric about changing a battery: they do it over and over again, so they know what they are doing, plus the 4 year warranty!

 

When the battery in my '18 E300 needed replacement, I left my car at a national chain car battery chain store. I went to pickup the car and discovered that they had trunk liners pulled looking for the battery. Needless to say, I drove to MB where they reassembled the trunk liners and installed a new battery in less than an hour.

I do not and will not ever buy anything from Walmart or similar stores due to a bad experience with untrained, entry level employees.

 

Great post and thread by @Long Islander

Last night, I got the "Stop Vehicle Leave Engine Running" prompt in my instrument cluster. After changing my battery myself a couple of hours ago, I'd like to add my experience.

Firstly, this is super simple y'all... it's not rocket surgery. It literally took me 18 minutes to complete, and I was not rushing.

The tools I used:

• 10mm socket for the terminal nuts (a 10mm wrench will work also).
• 2 small bungee cords to hold the positive and negative cabling out of the way.
• 13mm socket w/extention to reach the battery clamp bolt.
• Magnetic pick-up tool on the battery clamp bolt once loose, and this will pull the clamp out also because the battery clamp bolt is captured in the clamp.

Replaced my OEM battery with a Duralast Platinum H6 AGM from AutoZone for $249. Issue resolved.

 

When you take your car to a dealer to have work done it's the entry level employees doing routine things like oil change/battery replacement. I wouldn't be worried about having a retail place do it. Don't the auto part chains still do it for you no cost? Just bout any shop should do it for a half hour labor.

 

At least MB shop employees at the dealer I use are MB trained and have expertise to call on if there is an issue. That's rarely true at a mass market shop where they may have never worked on your Mercedes model.

 

I disagree: At my Mercedes dealer they have 'Express oil change": The employees are entry level. They are not the same as the mechanics who work on suspension, transmissions, etc.

There is an exception: When I took my Boxster in for transmission service in 2018, the mechanic working on the car was "Fritz". In 2018 the labor rate for 'Fritz' was $185 an hour. I also had the oil and filter changed.

When I got the bill for the oil change I started laughing. The service manager came out and asked why I was laughing. I said $285 for an oil change? How could that be? Mercedes charges $145.The manager said it was an hour labor. I said you put the car up on lift drain the oil, change the filter and put in new oil: how can that take an hour and besides the labor rate for employee changing the oil is much less than "Fritz": The manager said "Oh NO": your car was assigned to "Fritz' who does all the work on your car. That is the exception!

PS: The Boxster only had 9,800 miles was an automatic and had problems with the gear shift linkage, the gear shift was hard to put into gear. Never heard of that before and certainly not at 9,000 miles. The cost to repair was over $3,800 plus the oil change total bill was over $4,000. This was 5 years ago - today it could be double!. We sold the car within 2 months!

 

Your dealer experience is significantly different than mine.

 

Doesn't your dealer provide an "Express oil Change"? Most dealers do.

 

I’m surprised anyone would consider taking a car like this to Walmart. At places that don’t regularly work on Mercedes most of the guys can’t even figure out how to shift the car into drive or reverse let alone do mechanical work where things are setup differently than your average American or Japanese car.
If a mistake is made like putting the negative terminal for the positive it’s gonna cost like 5x more than most other cars to remedy the problem.

 

An H8 does fit. H8 is the same size as group 49. I don't know why they have different numbers. H8 seems to be the European designation for group 49.

 

Dealer service rep told me today that battery must be coded and registered after install which can lead to future electrical issues if not done. She said they get a lot of cars coming in from do it yourselfers and Auto parts stores who didn't register and they have to then register the battery to correct the messages or issues. They replaced mine today, the original lasted a little over 5 years but was on it's last legs the past year. Everything including auto start is back to normal now. Had them do a service A. Ended up going out of the dealer with a 1000 dollar charge for both things. Not cheap but at least everything was done by the book.

 

Coding and registering of a battery!!!!!

You are not serious are you?

see posts #1 and #12.

"A" Service is $225, so that means the dealer charged you over $700 for the battery and installation! Opps plus I forget coding and registering.

BTW, could you post what coding and registering is - because when I have my replacement battery done by Walmart for under $200 I want to make sure they do it!

Like you I want it "By the Book"!.

 

while you might save in the short run just dropping in a new battery and hooking it up in the long run it will cost you with far shorter battery life and other problems. Also the mb dealer gives a 2 year warranty on the battery and labor so if I have an issue I simply take it back to the dealer and they will take care it labor and all. Someone who had Walmart do it will probably be out of luck and they are gonna charge you labor to install a new battery and you might even get stuck paying for a new battery.

the other thing is service A including tax was around 325 not 225. Labor is very expensive these days it’s not like the MB techs are making 10 dollars an hour. Also I needed the recall done that updates the cars communication system which had to do with the SOS system. That takes a lot of time to feed the new program to the cars computer. I was at the dealer 4 hours yesterday. There was a man at the next desk talking to the service writer and I overheard him saying he had replaced his own battery and now was getting messages of stop vehicle leave engine running and also having other electrical issues..

here’s an article about the importance of registering a new battery in modern Mercedes cars. A lot of people don’t realize this and believe the cars pcm system just automatically adapts to a new battery when it’s replaced. Not true. The dealer put a Mercedes battery in my car yesterday the battery was 315 dollars which really isn’t too bad a price. The rest was labor though. The rest was labor plus service A. Programming and proper install takes time and time is money.

https://www.midtronics.com/blog/battery-registration-what-why-and-how-to-do-it/

 

I guess we are on different planets:

Service "A" is $225 not $325.

The battery from Walmart comes with a 4 year warranty. Your battery with a 2 year warranty.

If the battery was $315 + $225 for the "A" service than means the installation charge was $160.

There is no charge for programming updates.

Each time you walk into the Mercedes service center, I can see the big smile on on your service rep!

Let's leave it at this: you are convinced that only your Mercedes dealer should change your oil, put in a battery, change a filter, etc. and whatever they charge you are willing to pay.

 

There’s no doubt in my mind these cars are engineered to be future money making machines for Mercedes just as iPhones are designed as money making devices for apple computer. I’m sure there are engineers at the corporate level who’s job it is to engineer features making the end user more dependent on the dealers and as in the iPhone the apple stores.

There’s no question we pay a premium for driving cars such as these. To me it’s worth the expense as they are wonderfully driving cars and you don’t find interiors like these cars on just any car and the build quality is much better than most other cars. Not to mention safety. To me someone who is going to maintain a car like this at Walmart might as well just be driving a Chevy or a Toyota or Honda. In the long haul not doing this right your not gonna be driving a mb for the long haul if you don’t do things right.


From what I’ve seen at least around here Walmart auto center is a zoo. Busy as all heck with tons of people waiting for their cheap service. I believe if you did have a issue such as a error message in your mb Walmart is not gonna have a clue what’s going on with your car. They aren’t gonna have a clue that your battery is overcharging or undercharging and could not really care less because your battery was not registered to the car when it was replaced.

The electrical systems in Mercedes have always been known to be very finicky and I for one am not going to take a risk of creating other issues by not having things done right. My e450 is one of the best cars I’ve owned and it’s a long term keeper so I take things very seriously with the maintenance of the car.

 

For a simple battery swap, I think this is a bit of a stretch. I find it unlikely that anyone is bringing a Mercedes to Walmart for a tranny rebuild. Anyone can swap a battery, it's about as complicated as opening an umbrella.

Yes, resetting the Battery Management System (BMS) profile is a thing, however it's not a critical item, it is for fine-tuning battery charging optimization. Not resetting the BMS after installation of a new battery will not impede the vehicle operations, affect any other systems or cause any other problems other than possibly having an effect on long-term battery longevity.

Given all the deep logic in our cars, I find it extremely hard to believe this logic would allow an undercharging or overcharging condition to exist. It just doesn't make sense that a system with a BMS would be so fragile that a battery change would tear the whole system down.

If the reset was such a critical item, I would think there would be a clear warning label near the battery stating such. Also, since battery manufacturers are in business to make a profit, I would think my 3-year battery warranty would have an exception for Mercedes not resetting the BMS because they are seeing massive numbers of returns from Mercedes owners. But I don't think any of that is happening.

I'm happy with my $249 battery change and original BMS profile. No issues here and I can spend the money I saved on something meaningful to me.

If it's important to you to reset the BMS and it makes you more comfortable, then by all means do it. After all, it is the OEM procedure, so it's not wrong. How important it is, is debatable. I don't see it as critical at all myself.