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SLS Roadster battery problem

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Old Feb 21, 2018 | 02:06 PM
  #1  
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SLS Roadster
SLS Roadster battery problem

I have a 2012 SLS Roadster. Since delivery it has been plagued with an intermittent problem that completely drains the battery within a couple of hours. Must be like a dead short.
It has been in three different dealers for this sorting out and all have sold me a new battery and failed to solve the problem.

After 5 years of living with this i recognize some interesting signs.
As I approach the vehicle if the door mirrors are extended the battery will be dead. The doors will be locked. the red light on the starter button will be illuminated. the key will not open the door.
It appears the ignition is on but the car is locked.

I have to open the door manually using the slide out key.

The battery is recharged (my 200 amp charger has become my favourite item) and off we go again a few hours later.

Does anyone out there have an idea of what to look for?
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Old Feb 21, 2018 | 05:23 PM
  #2  
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From: Dallas, TX
2008 E63 wagon (1 of 62)
Definitely sounds like you have some incompetent dealers around you. Hooking into the CAN systems or doing some proper diagnosis would tell someone who knew what they were doing, but every battery draw issue can lead to some surprises.

My only other concern.. Are you leaving the charger on 200A charge rate for hours at a time?? I witnessed a couple technicians forget about their chargers and burn cars to the ground that way after forgetting about what they were doing.
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Old Jan 13, 2020 | 09:52 AM
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SLS Roadster
Because i'm fortunate enough to have other wheels; i polished the beast, disconnected the battery and put it's cover on, but now, 2 years later, i'd like to resolve this.

Yesterday i reconnected and it fired up instantly. however after about 1 hour sitting in the garage it did it again. Mirrors open, battery dead flat.

I have it narrowed down to a problem with the the wireless locking, it activates the systems radio, ignition, opens the mirrors,etc., but does not unlock the car.
The battery is drained within an hour.

I had stored the key at the other side of the house.

Is there anyone with a similar experience?
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