M3 Battery discharge overnight to 5.5V?

nomnomguy · 01-11-2016, 11:25 AM

This seems to happen randomly to my 2009 E90 M3. Two days ago I came down to find my car completely dead. This has happened before about a month ago but not since. I came down to find the car completely dead with all the doors unlocked with the windscreen wipers halfway up the windscreen. Nothing electric is turned on except for the backlights of the Hazard light button and the light switch. I checked the battery voltage with a multi meter. 5.5V. It took many tries and about 15 minutes before the engine finally cranked. Then it gave me transmission malfunction error (which was caused by low voltage). I let the car idle for 15 minutes, then restarted the car and it drove fine. Yesterday i came down hit unlock on the remote and started the car normally. Today I came down to find the car in the same state with the battery discharged to 5.5 volts again. Any help would be appreciated

BimmerRookie · 01-11-2016, 11:41 AM

Go for a new battery! If you're on your original OEM battery and not battery tending every night, then it's about time for a new battery.

Move Over · 01-11-2016, 12:41 PM

Quote:

Originally Posted by nomnomguy

This seems to happen randomly to my 2009 E90 M3. Two days ago I came down to find my car completely dead. This has happened before about a month ago but not since. I came down to find the car completely dead with all the doors unlocked with the windscreen wipers halfway up the windscreen. Nothing electric is turned on except for the backlights of the Hazard light button and the light switch. I checked the battery voltage with a multi meter. 5.5V. It took many tries and about 15 minutes before the engine finally cranked. Then it gave me transmission malfunction error (which was caused by low voltage). I let the car idle for 15 minutes, then restarted the car and it drove fine. Yesterday i came down hit unlock on the remote and started the car normally. Today I came down to find the car in the same state with the battery discharged to 5.5 volts again. Any help would be appreciated

Probably time for a new battery. I went with a Die Hard from sears with no ill effects, others say "OEM only". Bosch makes a good one. Look for a 92AH with 850+ CCA. Then, register accordingly.

m3fanboi · 01-11-2016, 01:03 PM

On a related note, I have a question.
I have a brand new factory OEM battery installed in September. I plan to travel for 3 weeks. I live on SoCal. Would I really need to get a battery tender, or just take my chances when I get back? What say gurus?

javarithms · 01-11-2016, 02:58 PM

Quote:

Originally Posted by m3fanboi

On a related note, I have a question.
I have a brand new factory OEM battery installed in September. I plan to travel for 3 weeks. I live on SoCal. Would I really need to get a battery tender, or just take my chances when I get back? What say gurus?

You should be fine if your battery is not really old. To be safe you could just disconnect the negative cable and then you won't have any draw on the battery.

Lunker325 · 01-11-2016, 03:29 PM

I had a flaky EDC module in my car that was parasitically draining the battery. Not as fast as yours, but would throw errors every once in a while. Replaced the module and all has been well since. The module is on the right hand side of the trunk behind the carpet if you wanted to pull the power to it and see if the draining stops.

mjposner · 01-12-2016, 06:32 AM

"To be safe you could just disconnect the negative cable and then you won't have any draw on the battery." I think that could cause issues with certain equipment and throw error codes that will not reset.

I have read that if you are leaving for a few days to lock the car to reduce battery drain. Not sure why.

I have left the car up to 10 days without ill effects.

vsix · 01-12-2016, 06:40 AM

Man, really looks like you need a new battery+ registering it.

nomnomguy · 01-12-2016, 10:46 AM

Quote:

Originally Posted by vsix

Man, really looks like you need a new battery+ registering it.

Last month the dealer tested the battery they said it was fine. I think it may be a parasitic draw. The issue is it doesn't happen every day and is very hard to reproduce.

DSilk · 01-12-2016, 11:16 AM

Disconnecting the battery will put you in the position of having to reset all of your stored settings, including seat memory and radio presets (among other things).

01-11-2016, 11:25 AM	#1
nomnomguy New Member 2 Rep 8 Posts Drives: '09 BMW M3 (E90) Jerez Black Join Date: Sep 2015 Location: Palo Alto, California iTrader: (0)	M3 Battery discharge overnight to 5.5V? This seems to happen randomly to my 2009 E90 M3. Two days ago I came down to find my car completely dead. This has happened before about a month ago but not since. I came down to find the car completely dead with all the doors unlocked with the windscreen wipers halfway up the windscreen. Nothing electric is turned on except for the backlights of the Hazard light button and the light switch. I checked the battery voltage with a multi meter. 5.5V. It took many tries and about 15 minutes before the engine finally cranked. Then it gave me transmission malfunction error (which was caused by low voltage). I let the car idle for 15 minutes, then restarted the car and it drove fine. Yesterday i came down hit unlock on the remote and started the car normally. Today I came down to find the car in the same state with the battery discharged to 5.5 volts again. Any help would be appreciated
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01-11-2016, 11:41 AM	#2
BimmerRookie Major 469 Rep 1,320 Posts Drives: E93 Cavalier Z24 M3 Join Date: Jan 2014 Location: Austin, TX iTrader: (0)	Go for a new battery! If you're on your original OEM battery and not battery tending every night, then it's about time for a new battery.
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01-11-2016, 01:03 PM	#4
m3fanboi New Member 6 Rep 25 Posts Drives: Bmw m3 Join Date: Mar 2015 Location: San diego iTrader: (0)	On a related note, I have a question. I have a brand new factory OEM battery installed in September. I plan to travel for 3 weeks. I live on SoCal. Would I really need to get a battery tender, or just take my chances when I get back? What say gurus?
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01-11-2016, 03:29 PM	#6
Lunker325 First Lieutenant 94 Rep 398 Posts Drives: E70 X5M / 991.2 C4S Join Date: Mar 2014 Location: Columbus OH iTrader: (4)	I had a flaky EDC module in my car that was parasitically draining the battery. Not as fast as yours, but would throw errors every once in a while. Replaced the module and all has been well since. The module is on the right hand side of the trunk behind the carpet if you wanted to pull the power to it and see if the draining stops. __________________ '17 Porsche C4S Sapphire Blue Metallic / Bordeaux Red - Softronic tune - Soul Sport Cats - Soul Exhaust '13 E70 X5M Black Sapphire Metallic / Bamboo Beige - Full Dinan Suspension - Dinan Exhaust - BPM Sport Tune - xHP Flashtool Transmission Tune
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01-12-2016, 06:32 AM	#7
mjposner Brigadier General 898 Rep 3,071 Posts Drives: 2020 Z4 40i Join Date: Mar 2011 Location: Southwest Florida iTrader: (3)	"To be safe you could just disconnect the negative cable and then you won't have any draw on the battery." I think that could cause issues with certain equipment and throw error codes that will not reset. I have read that if you are leaving for a few days to lock the car to reduce battery drain. Not sure why. I have left the car up to 10 days without ill effects. __________________ Previous BMW: 16 M4, 13 M6; 14 M235i, 12 BMW M3; 11 BMW M3; 08 BMW M3; 08 BMW Z4M; 04 X3; 02 M3 Convertible; 02 M3; 00 M Roadster; 94 325 convertible; 92 325i Convertible; and 85 635csi My Car Photo Blog: http://carfisheye.blogspot.com/
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01-12-2016, 06:40 AM	#8
vsix Lieutenant Colonel 602 Rep 1,611 Posts Drives: M3 E92 sold, M4 F82 Join Date: Nov 2012 Location: ATL iTrader: (0)	Man, really looks like you need a new battery+ registering it.
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01-12-2016, 11:16 AM	#10
DSilk Major 550 Rep 1,148 Posts Drives: 2008 BMW M3 Coupe Join Date: Jun 2015 Location: South Florida iTrader: (0) Garage List 2015 Jaguar XJ [0.00] 2015 Jaguar XF [0.00] 2014 VW GTI [0.00] 2008 BMW M3 Coupe [0.00] 2007 VW Passat 2.0T [0.00]	Disconnecting the battery will put you in the position of having to reset all of your stored settings, including seat memory and radio presets (among other things).
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