Time for new battery...?
Battery has performed flawlessly so far.
But wondering if it's prudent to be proactive & go ahead to replace both batteries now, or just wait until first signs of red light or sputtering starts...?
Don't want my wife to be stranded somewhere with battery issues...
Thanks,




Still weakening battery will give you some warning. Common is slow cranking on cold morning.
Than I experienced that weak aux battery was taking long time before ECO stops would start to make their job.
Bottom line - IMHO the only good proactive is getting new car..
Everything else is a judgement call.




Whole different story.
In older MB we had batteries lasting 13 years, when I read reports about 17 years.
But again, new system when saves environment, kills the batteries

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I have the testers Kent shows and it does take 2 different testers to fully test the batteries.
Sometimes battery will keep voltage, but will not deliver high amp, sometimes it it delivers high amp, but capacity is low and when it starts the engine, keeping the cabin lights for few minutes will run it low.
Pretty tricky business.
The Best of Mercedes & AMG
They have Econo 20-month warranty for $110, Performance 40-month warr for $155, & Lifetime with Lifetime replacement (as long as you own the vehicle) for $210.
So seems like if we keep our E for another 4+ years, the Lifetime battery option makes sense.... ?




When you are taking your car to dealer, - you will qualify for roadside assistance who will replace battery at your home free of labor charge.
FCP sells MB brand batteries with lifetime replacement (I just bought smaller aux battery from them as it come only $15 more than from other guys with 24 months)
Than in last years PepBoys have the best deals on Bosch (96 months on flooded) or Champion batteries. Check their internet specials and current coupons.
Thanks to feedback here the Champion from Pep Boys was the best warranty and pricing.
I also wondered at the time about changing the original dash battery but decided to leave it - as mentioned the car will give an initial warning of low voltage.
When I got in the car to go to work yesterday, the side mirrors barely folded out. When I tried to start the car, absolutely nothing. Dash, electronics, lights... Nothing. Good thing it happened at home in my garage.
I had just taken my car for dealer maintenance 3 weeks ago. At that time the battery apparently tested fine.
The good news is that the dealer determined that the battery failed early, and replaced at no charge under warranty. The battery came with car when new. The battery lasted 3.5 years.
As I know that if you dont use start-stop system continuously then the battery life will increase.
I asked MB service to check the battery they said the voltage a little bit low, then they put on charge. But before that I dont have any problems (also till now). I suggest ask MB service or a good technician.




Strange that with morning warning, after some drive the battery was still good and did ECO stops. New battery seem to make more stops, but system has too many variables to judge.
From what I read, ECO stops are done by aux battery, so they not suppose to affect main one.
I drive 1 car with ScanGauge and have volts on it, what shows charging voltage in the morning at 14.7V and I know this is shortening battery life.
For years I compare my MB to Ford trucks I have.
When older MB charging operate at 13.9V- batteries last for decade. Ford charging is at 14.5V and seldom batteries last more than 4 years.
New MB regenerative charging seem to make batteries lasting 3 years, when 4 is good result.




Incidentally, unless you DIY it is hard to find a battery for M-B vehicles. Most auto parts places won't install them due to possible complications with M-B electronics. I tried several a year or so ago and none would install one.
Nothing against them, but most don't have knowledge of the secondary battery that leaves the electrical "live" even with primary battery disconnected.




Usually the job is given to trainee, meaning kid who was flipping burgers 2 days ago.
It happen that serviceman cross connected the battery and fried $5000 worth of computers.





There is always a set of jumper cables in the trunk, just in case. But I've given more jumps to other people than I have to my own vehicle(s).
This way, a battery can be allowed to last 4 years, or up to 8 years before it needs to be replaced... the battery decides for me. Battery technology sometimes changes, so there's no need to buy a new battery ahead of its dead date.
In short, my wife has never been without a car due to a dead battery.
Last edited by DFWdude; Apr 3, 2019 at 06:20 PM.




Most batteries are private label. Some battery facts, There are only 3 major automotive starting flooded battery manufacturers in the United States and four absorbed glass-mat (AGM) starting battery manufacturers in the United States.
The majority of Mercedes are equipped with a AGM battery.
Down here in the south the heat is hard on batteries a normal flooded battery only lasts 2 to 3 years max where the AGM lasts 4 to 5 years.
The AMG cost a bit more but
They are robust and do not leak or spill and they are relatively free from freezing damage.
Very little water loss
The internal resistance of the battery is very low so they charge faster and can take a heavy discharge without damage about 50%
Low discharge rate when stored for extended periods
After a bit of research, I decided to get a Champion AGM battery, in H8/Group49 size because a thread here on MBWorld said it will fit, even if Pepboys' website cross-referenced to a H7/Group94R size instead. The fact that Pepboys currently offer a 25% discount if you order or buy through the web, and are currently running a $40 rebate on this battery helped a bit in my decision-making.
The total, after rebate, with taxes, came to under $120. For the data geeks, the SOLAR BA9 showed this battery as outputting >1000CCA, straight from Pepboys, even though it is rated at 900CCA.Installation was pretty straight-forward. To extract the battery, after removing the cabin air diverter (?), I merely had to use a 13mm long extension socket for the bolt holding the battery down. I then hooked up my CTEK to maintain standby power to the car, and used the 10mm socket to loosen the terminals, obviously taking care not to arc anything since there was still applied power. I had to detach the overflow tube and plug from the old battery, and that was a bit fiddly. The original battery was a H7 Varta that was made in Germany. It was heavy, but not as heavy as the H8 Champion, also surprisingly made in Germany, that was purported to weigh 61 lb. It was a somewhat tight fit, but the new H8 battery went in fine once you get the wires out of the way. After buttoning everything up, I topped up the new battery with my CTEK; that took surprisingly long, given it was a new battery with a 4/19 date stamp. Oh well, I guess it was hungry.
I can't say my car started up quicker or more confidently. To be honest, the first startup after battery replacement felt and sounded the same as with the old battery – promptly and smartly. However, I now have confidence that I am less likely to be stranded with a suddenly dead battery. Plus it's another thing I don't have to worry about for quite a few years, especially as I'm planning a nice road trip with the car in summer.
PS: it may be interesting to note that the Varta and Champion appear identical, apart from their dimensional differences (H7 vs H8 sizes) – same molding shape, including cutouts at the base and other details of that nature. I'm guessing they were probably from the same factory.





Most batteries are private label. Some battery facts, There are only 3 major automotive starting flooded battery manufacturers in the United States and four absorbed glass-mat (AGM) starting battery manufacturers in the United States.
The majority of Mercedes are equipped with a AGM battery.
Down here in the south the heat is hard on batteries a normal flooded battery only lasts 2 to 3 years max where the AGM lasts 4 to 5 years.
I am genuinely confused whether OEM MB batteries today are flooded or AGM. One might think that MBs most consistantly popular model -- the E-Class -- would have the latest tech in batteries, but my experience so far in not proving out. My W212 was built on July 20, 2015. According to CarFax, the original battery was replaced under warranty by the previous owner in June 2017. That's just 23 months on that battery.
This 2017 battery was replaced again, under warranty, by the dealer for me on April 17, 2019 (just yesterday). That's 21 months life.
Accordingly, in my experience, these batteries struggle to make a mere 2 years between replacemets. If these are truly AGM battery technology, then please give me the old fashioned flooded batteries, instead. Those MB batteries last twice as long at least (5 years on average) in my old 2001 C320. IMO, I am NOT convinced that these higher tech batteries are any improvement at all. High tech is supposed to improve our lives, not require two-three steps backward.
Last edited by DFWdude; Apr 17, 2019 at 08:37 AM.



