R-Class (W251) Produced 2006-2013: R320CDI, R350, R420CDI, R500

Dead Battery/Drain

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Mar 12, 2013 | 10:14 PM
  #1  
efzauner's Avatar
Thread Starter
Super Member
15 Year Member
Photogenic
Liked
Loved
 
Joined: Jul 2009
Posts: 938
Likes: 53
From: Montreal, Canada
2005 C240 2011 R350
Dead Battery/Drain

Last winter I had trouble starting the car after only a few days in our heated garage... MB replaced the battery under warranty. Did not find any other problem.
This winter it would not start after 5 days parked at the airport. Mind you it was cold maybe -15C but my other cars never have a problem starting

Then twice since then it would not start. Today it was completely dead. I had to use the mechanical key to open it. And I drove in 2 hours 3 days ago.

I have read the threads regarding blower motor staying on, one thread claiming a bad battery cable, another with some bad module under the steering wheel.

Any other people with this problem?
Reply
Old Apr 4, 2013 | 09:39 PM
  #2  
bensitto's Avatar
MBWorld Fanatic!
 
Joined: Jan 2003
Posts: 1,338
Likes: 34
From: Germantown, MD
S550, R350, GL550, ML63 AMG
My 08 had a similar problem. Sometimes it's the rear lift gate module which stays on even after the rear hatch closes. Also, the locking plate for the rear hatch might have to be adjusted.

Get it diagnosed at your dealership, hope you are still under factory or extended warranty! There's definitely a draw coming from somewhere.

Good luck.
Reply
Old Jul 2, 2013 | 08:42 PM
  #3  
Spud_Racer's Avatar
Member
 
Joined: Dec 2012
Posts: 168
Likes: 0
From: Connecticut
R500 + SLK55 AMG
We found a dead battery in our 07 R500 a few weeks ago in warm weather. The car hadn't been driven in about two weeks. The battery is less than a year old. I called roadside assistance and had it towed to the dealer for some warranty love. They had the car for 10 days and couldn't find a draw. They also said the battery checked out fine.

Fast forward a few weeks. This past weekend it was deja vu. Only this time the car hadn't been driven for one week. This time it wouldn't respond to jumper cables or a trickle charger. So, another call to roadside assistance. All they did was jump it with a portable battery but the POS did start.

They also told me that contrary to urban myths on this website, Mercedes roadside assistance WILL NOT replace a battery on an R500. They said to schedule an appointment at a dealer. The dealer said 2 hours to replace a frickin battery! That's ridiculous. Any design that requires a skilled technician to spend 2 hours replacing a battery is a poor design.

So, the dealer will not be replacing the battery. Sears sells an AGM equivalent for $145 (US). Mercedes will however be getting the car back to find the source of the current draw. No car battery less than a year old should lose all of its charge in seven days in 80 deg F weather.
Reply
Old Jul 2, 2013 | 09:35 PM
  #4  
efzauner's Avatar
Thread Starter
Super Member
15 Year Member
Photogenic
Liked
Loved
 
Joined: Jul 2009
Posts: 938
Likes: 53
From: Montreal, Canada
2005 C240 2011 R350
Dealer did find a defective rear parking proximity sensor SAM module that was drawing.

I am appaled generally at the poor troubleshooting skills and tools that the dealer has. They should be able to hookup a current draw sensor to main distribution and let me drive it for a week. Had they not found the problem I would have built on myself!

as for time required to change the battery, well it is under the drivers seat. 2 hours is a bit much, maybe 90 minutes is better. An hour for the junior mechanic that does this once a week... this is not rocket science!
Reply
Old Jul 3, 2013 | 08:30 AM
  #5  
bensitto's Avatar
MBWorld Fanatic!
 
Joined: Jan 2003
Posts: 1,338
Likes: 34
From: Germantown, MD
S550, R350, GL550, ML63 AMG
The battery is under the passenger seat and there are directions in your car's manuals on how to replace it without removing the seat. I've done it myself several times when I had the same issues. it's not easy, but I'm able to swap out a battery in under 30 minutes.

Dealer removes the seat because it's a tight and uncomfortable removing it how the manual directs to do this and the battery is huge and needs to go in and out at an angle. Space is very limited. If I had more time I probably would remove the seat too.
Reply
Old Jul 3, 2013 | 11:32 AM
  #6  
Yu Chem's Avatar
Junior Member
 
Joined: May 2013
Posts: 55
Likes: 4
From: Montreal, Canada
2012 R350 BlueTEC
Recommended brand for battery replacement

My dealer advised me that my battery is 'weak' during last maintenance job. They quoted ~$650+tax for replacement ($400 for battery and 2 hours work). I refused, thinking I could do myself.

I thought about Interstate, it is still pretty expensive, I think ~$300 + tax and I could only buy it at some mechanic shop in Canada which wants they commission too.

What battery brand and type would be the best replacement for the stock OEM?
Reply
Old Jul 3, 2013 | 12:23 PM
  #7  
pacoman's Avatar
Member
 
Joined: Dec 2010
Posts: 89
Likes: 0
2008 R350 4-matic
This is what I put in my 2008 r350 last year. http://www.oreillyauto.com/site/c/de...0423&ppt=C0005
Reply
Old Jul 3, 2013 | 01:08 PM
  #8  
Spud_Racer's Avatar
Member
 
Joined: Dec 2012
Posts: 168
Likes: 0
From: Connecticut
R500 + SLK55 AMG
I think I'm going with the AGM group 48 battery from Sears for $140.

http://www.sears.com/diehard-advance...1&blockType=G1

Not sure this helps Canadians though. Do you have Sears in Canada?
Reply
MB World Stories

The Best of Mercedes & AMG

story-0

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-1

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-2

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-3

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-4

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-5

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-6

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-7

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-8

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
story-9

10 Most Reliable Mercedes-Benz Models You Can Buy Used

 Verdad Gallardo
Old Jul 3, 2013 | 02:14 PM
  #9  
efzauner's Avatar
Thread Starter
Super Member
15 Year Member
Photogenic
Liked
Loved
 
Joined: Jul 2009
Posts: 938
Likes: 53
From: Montreal, Canada
2005 C240 2011 R350
Originally Posted by bensitto
The battery is under the passenger seat and there are directions in your car's manuals on how to replace it without removing the seat. I've done it myself several times when I had the same issues. it's not easy, but I'm able to swap out a battery in under 30 minutes.

Dealer removes the seat because it's a tight and uncomfortable removing it how the manual directs to do this and the battery is huge and needs to go in and out at an angle. Space is very limited. If I had more time I probably would remove the seat too.
I also removed the seat, it is very easy to do, just 4 bolts. But you have to be carefull. You can tilt it forward with out disconnecting any wires. If you disconnect, becarefull not to apply power because if you disconnect any of the SRS wires it will flag a code, and you will have to to the dealer to have it cleared. I did this on the drivers side. I thought I had every thing off and yet it still pulled a code.. luckily dealer cleared under warranty
Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 02:55 AM.

story-0
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-1
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-2
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-3
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-4
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-5
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-6
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-7
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-8
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE