Battery flat / drained again..

Wessa1

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Joined
Jan 22, 2018
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Location
New Zealand.. Ex-Essex..
Your Mercedes
2008 E550 (Silver of course)
Hi All,

So my battery on my 08 E550 has gone flat again after the car has been sitting outside for two days.
I have previously had a new battery fitted only a few months ago.

I have booked it in to go back to where i bought the car last year. They are pretty good.
They said to me it sounds like a module is not shutting down and draining the battery.

Its going to an electrician who will need it for a few days to run a diagnostic so to work out where the drain is coming from.

When i used the car everyday, the voltage reads fine and starts ok. Its just that two day of none use that does it.

Is this a common issue? What are your thoughts guys?

Thanks in advance. ;)

Gary.
 

Submariner1

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Sep 3, 2016
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Location
Windsor Berkshire
Your Mercedes
CL500 2009 5.5
Do you have an iCarsoft MBII?
Worth looking at the modules and see if any do t shut down? And then take it from there or better get an initial Star printout.

My drain was down to a defective brand new genuine MB Battery.
Lots went undervoltage and a few SAMs never shut down.
At one stage the drain was 8A! Thats pretty huge!

Replacmt. Battery resolved everthing :)
So, dont rule it out, as this technician said “3 years ago you never saw this, but in the last couple of years I have come across 3”
 

AMGeed

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Jan 18, 2009
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Poole, Dorset
Your Mercedes
2014 W212 E63 Biturbo
Yes its a common theme on the W211, W219 and R230 to have battery drains that are difficult to pin down.
Get the electrician to look at the Comand not shutting down, and door and seat control modules draining the battery.
I expect he'll do a current draw on all the fuses first. A total of 65ma is considered acceptable.
 
OP
Wessa1

Wessa1

Active Member
Joined
Jan 22, 2018
Messages
43
Reaction score
14
Location
New Zealand.. Ex-Essex..
Your Mercedes
2008 E550 (Silver of course)
  • Thread Starter
  • Thread starter
  • #4
Do you have an iCarsoft MBII?
Worth looking at the modules and see if any do t shut down? And then take it from there or better get an initial Star printout.
My drain was down to a defective brand new genuine MB Battery.
Lots went undervoltage and a few SAMs never shut down.
At one stage the drain was 8A! Thats pretty huge!
Replacement. Battery resolved everything :)
So, dont rule it out, as this technician said “3 years ago you never saw this, but in the last couple of years I have come across 3”

No, i don't have any software that i can use to check the car. Probably best too, i would only confuse myself lol..
I did mention the battery should be the first port of call even though its a recent renewal.

Yes its a common theme on the W211, W219 and R230 to have battery drains that are difficult to pin down.
Get the electrician to look at the Comand not shutting down, and door and seat control modules draining the battery.
I expect he'll do a current draw on all the fuses first. A total of 65ma is considered acceptable.

Its off to an electrician this morning.. They want it for the week. I also have a warranty on the car so I don't care what i cost for a change..
I will let you know the outcome.

Thanks again Fella's.

Cheers.
 

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