Weak battery question
 

Getting cold in my neck of the woods , -20 celcius.

I don’t do many long trips. I went to the store , shut off engine for 3 mins, then tried to start and you can sens tremendous effort for the car to start , weak battery. It’s done this 3 time now in same scenario. And it’s only after a short trip of 5 km’s.

This is CPO vehicle, owned since June 2018. 2016 E63 is the vehicle.
If the battery is indeed weak, would this be covered by warranty of some sort?
IF it’s not, can you recommend a battery? { I don’t need the dealer to over charge me for this }.

Thanks for your help.

My batteries are coming up on 4 years old, i went to my local dealer who gave me 10% off and got both the main battery by the engine, and the aux battery in the trunk for about 440$ with tax.. Good piece of mind just to be safe and not stuck anywhere.

My batteries were still in good condition and i usually leave the car on the oem mercedes trickle charger when i know im not driving it for a while or i want to juice up my battery good.

Good news in after looking at WIS service manual, it seems our batteries are plug and play, no programming needed.

There's also that $150 off $300 service coupon and someone else mentioned that it works on batteries.

But if you don't drive it much, it probably just needs a good charge. If you drive around too much with a weak battery, that also kills it faster. Don't try and charge a frozen battery though.

I would just get a 10 amp battery charger or less and let it slowly charge up. Higher currents aren't that good for the battery and it may out gas hydrogen so under 10 is better. I also wouldn't leave a battery tender hooked up, the ones that go bad tend to end up frying your battery.

Here's a cheap 8 amp one for $18.

Thx Peter.

It's the answer I wanted to know most, if it is under CPO warranty since I've only have the vehicle 6 months.... I wasn't expecting that I need to replace battery... at my cost.

I'm not sure if you're covered for batteries under the CPO warranty, but if you still have the original factory warranty the battery should be covered.

It could be a bad battery. I just got my 2016 GL350 with only 6800 miles a couple of weeks ago. The first week I had it after it was parked in my garage I couldn't start it. I took it to the dealer after I jump started it. They checked the battery and sure enough it was bad. They replaced it under MB warranty. So, yes, the battery is covered for 4 years/50K miles, whichever comes first.

thx much

2016 vehicle. Covered. Period.

I bought my old 2011 3 years old, and in 2015 (3 months shy of factory 4 year warranty expiration) A dealer tech drove to my house and installed a brand new battery in my garage at no charge.

Of course everything I just wrote is predicated on the fact that it is the battery, and not your charging system as Peter mentioned. But then that is covered too. You are basically covered for everything until 4 years after the date of the car's original purchase.

Good Luck

Thx Vrod .

An update on this for you all, I brought the vehicle for service and mentioned the battery issue. The response from them was that the battery is "ok" and it needed to be fully recharged.
Would that make sense. Can I verify this myself somehow , that the battery is ok?

I just don’t want to prolong this issue temporarily and then find out that indeed the battery was defective and then be outside the warranty window.
Many thanks.

If you don't drive the car enough, you should just get a battery charger to keep it charged. Short trips just won't be enough to keep the battery charged. Once it's fully charged, you can take it to any auto parts store and have them do a load test on the battery to see if it's still good. If MB told you it just needed to be charged, they probably already did a load test on it and it came back good. A battery that never gets fully charged won't last as long as one that's fully charged.

I also have an update. My 2015 battery just started acting up. It is supposed to have battery protection while a radio or such is on without the engine running. I often let the music play in the driveway while detailing her or other activities. As many of you know, after about 10 minutes or so it will pop up a message saying basically "start the engine or the radio will be turned off"

So on Sunday, while doing xmas lights on the house, I missed the message, but it just turned off the radio. Usually this is no issue. However, Sunday when I went to start it, it would barely turn over and would not start. I let it sit for 20 minutes, as batteries do have a self regenerating ability to an extent. I then started her right up. She has acted fine since. Even in the colder morning time. I am scheduled for a dropoff for the O2 sensor next Monday. I plan to have them do a load test on the battery at that time. I suspect it will fail.

My 2011 battery was replaced just inside of the factory warranty as well and it behaved similarly in the weeks prior to quitting altogether.

I will update here again next Tuesday with what they find/do.

Well, did another few short trips, mile or 2, stop, turn off car, start again 3 or 4 minutes later, and same symptoms … large strain on first turnover to start.

Emailed dealership to schedule another appointment. :smash:

Dropping the vehicle off after hours. They said the will do " cold test" the next morning. Should be -15 celsius .

my rear battery was bad which controls the ECO function, so they did cover that under full factory warranty on my 2015. Interesting and coincidental that my main battery this morning wont turn over in the 17 degree chicago cold so we'll see what the dealer says about that now that im in to my CPO warranty

having this same issue Vrod with my battery this morning! i will put it on the trickle charger if it doesnt start in another 2-3 hours when i try it again.

Don't know why there's so much fuzz over a battery. Mine started cranking slower and slower, so I replaced both batteries with Exide AGM 80AH and the aux with 13ah. Total cost 200.- Replacing them took me 30 min.
And off you go.
Ed

No fuss being made. The vehicle is under warranty so I wanted to ask members if it was covered etc.
Further more , the dealership says the battery is good, yet , I see the same symptoms.
Perhaps you did not read the entire post.

I did, I just try to help you with getting your car back on the road with a saver feel about your starting issues. You're possibly spending days going back and forth with the dealer where you can take matters in your own hand and replace the whole battery pack for some 200.- Typically, batteries are consumable parts and may not be covered anyways.
My suggestion, take a voltmeter and measure your voltage at idle. If you're at 14+ V, then you know you don't have alternator issues. Check if your battery contacts are tight and make good contact, no corrosion or other build up on the poles.
Since your dealer already checked that, replace the batteries and you should be fine for the next few years. Minimal effort.
Good luck,
Ed

Thx for the feedback. If the vehicle was not under warranty , yes, I would go purchase a new battery on my own , even without knowing what the problem is.

Since it is under warranty , I want the proper diagnosis , and that then the proper solution is made by the dealership.

The dealership is 1.9 miles form my office. They provide me with a loaner vehicle. So, for me , it is not much trouble to need to visit them.