Page 1 of 2

What is typical battery degradation?

Posted: Mon Jan 07, 2019 7:26 pm
by hallcp
I am looking at a B-Class on one of the local used car lots. It seems like a wonderful car, but I'm a little disappointed in the range. This is a 2014 with 22,000 miles on it. The battery at full charge appears to have 62 miles range. Is that normal battery degradation for these cars? One thing I read implied the warranty would kick in if the level dropped below 70% within 8 years or 100,000 miles. This car would be well on it's way to that. (.7 * 85 = 59.5)

What do you guys think?

[ PS - I tried searching the forums but I didn't find anything, could be user error, so sorry if this has been discussed 100 times before. ]

Re: What is typical battery degradation?

Posted: Tue Jan 08, 2019 7:38 am
by JeffRay

I leased a 2014 for 3 years and reupped for 2 years on 2017. Gotta love the big cabin feel in a small footprint. 22K in 5 years is about right for regular but not excessive use.

To your question.

1. The indicated range is a guess like in a gas car, depends on last miles driven. You may want to reset the indicator and compare charge level against reset range. It is a very rough indicator of battery health.

2. Best is to take the car to a MB dealer who can run out battery report and check car out for you. The battery test is a annual requirement and if they know what they are doing (questionable), they can access the past reports online.

3. You need to find a local MB dealer who can service the car. Stuff will happen (per posts) and if there is any remaining warranty on the car and it ports to you, you still need a place to have it dealt with.

4, You didn't find much here because as far as I can remember, severely degraded battery has not surfaced in these cars yet. They are Tesla batteries and motor and others have found useful info on other car forums.


Not all 2014s had the option to top up the battery to 90 percent of capacity. GlennD has posts that state that MB sets max charge of batteries at 80 percent (but translates to 100% in car indicator) Confused yet?

The option gives 12.5% more range and I use it all the time, particularly when the outside temps drop below 50 degrees.

You will want to consider daily use, places to charge, and if you are so fortunate, a dedicated plug in your warm garage.

I clearly get by even though I live in an apartment building and park on the street. It is something you are well advised to work out before you buy or lease to anticipate the dreaded "range anxiety" attacks. Not recommended but I have driven both this car and gas cars down to 0 range and managed to make it to a fill up location.

Good luck.

Re: What is typical battery degradation?

Posted: Tue Jan 08, 2019 8:03 am
by hallcp
Thanks JeffRay, this is all very helpful. I visited my local dealer and they actually had a tech who has worked on these cars (there's at least one other one in town!). As near as he could tell there was no record of previous battery maintenance, so that kills the battery warranty. But I have the car for a day-long test drive today and so far the range estimator is definitely conservative. I'll try that reset thing at lunch if I can find the setting.

Re: What is typical battery degradation?

Posted: Tue Jan 08, 2019 8:25 am
by rrattie
If you are in an area that is cold right now that can affect the range also. I have the same year model with 12k miles on it (1.6k my own) and when the temp is above 60 I can see 84 miles range, but 60 - 70 are what I'm seeing when temps his 30 - 50 outside.

Re: What is typical battery degradation?

Posted: Tue Jan 08, 2019 9:34 am
by hallcp
The temperature last night was in the 40's, now in the daytime it's about 55. So I guess that could account for some of the loss.

Thanks for your info!

Re: What is typical battery degradation?

Posted: Tue Jan 08, 2019 7:34 pm
by hallcp
Bingo! I reset the ECO display (and everything else I could find) and full charge came back up to 72 miles. That's more in line with what I expected. And as you say, from then on I could tell that the indicated range was very conservative. I could drive 9 miles and the range would drop only 6, that kind of thing.

I was a little disappointed that Mercedes won't honor the warranty without annual inspections. That doesn't even sound legal (neither Tesla or Chevy has any such requirement). That and the used car dealer refusing to deal on the price has killed the deal for the moment.

But I really enjoyed my 24-hr test drive and the local Mercedes dealership was very helpful in answering questions, as of course were the folks who responded on the forum.

What a nice car.

Thanks so much!

Re: What is typical battery degradation?

Posted: Wed Jan 09, 2019 10:20 am
by JeffRay

Re: What is typical battery degradation?

Posted: Sat Jan 12, 2019 8:21 pm
by hallcp
Hey I thought I'd add an update to this thread. The used car guy called me back with a deal I couldn't refuse and I am now the proud owner of 2014 Model B!

So now there are apparently 2 of these cars in Raleigh, NC.

Re: What is typical battery degradation?

Posted: Sun Jan 13, 2019 7:44 pm
by JeffRay
Uh, other than a horse head in the bed, any chance you can clue us in? I offered to buy out my 2014 lease for the $15K they would have sold it for at auction, but my dealer declined.

Re: What is typical battery degradation?

Posted: Mon Jan 14, 2019 9:19 am
by hallcp
They had it listed as $15,989. I offered 15,000 and they refused. Four days later they called back and countered with $15,500. But then of course mysterious other fees were tacked on and it was $17,087 to get out the door.

In refusing my original offer they pointed out that $15,989 was cheaper than any other one on the internet (which appeared to be the case) and that could sell it for wholesale and make more $$$ (maybe).

In any case, I just don't think they could sell it here in Raleigh at any price, except to an EV enthusiast. Although after the fact I poked around and I guess 90% of the Leafs on the road today have comparable range.

I can't imagine that the local dealer knew what he was getting when he bought one of these. But it may be that things are changing. They had a Cadillac of some sort that was electric (Voltec?) and they're beginning to see Teslas.