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BMW 5 Series - Battery Problem

35 messages,  Last post on Mar 20, 2013 at 5:58 AM

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What is this discussion about? BMW 5 Series, Electrical

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#1 of 35 BMW 5 Series - Battery Problem by bizzymum

Jan 03, 2010 (5:00 am)

I bought my BMW 520 (first registration Sep 01) in Nov 2008. In Jan 09, the battery was going flat often. Since then, the battery has been changed 4 times, alternator changed twice and an electrician has checked the drainage system but i tried starting the car yesterday after a new battery was fitted on Thursday 31st Dec 09 and it was flat. I dont know what to do now. Help.

#2 of 35 Re: BMW 5 Series - Battery Problem [bizzymum] by roadburner

Jan 03, 2010 (9:36 am)

Replying to: bizzymum (Jan 03, 2010 5:00 am)
Is the electrical tech familiar with late model BMWs? The current draw must be checked after the motor has been shut down and all doors, hood, and trunk are closed in order to see if the car's electronics are going into "hibernation" properly. Have you noticed any problems with the climate control fan? A bad final stage unit(AKA 'hedgehog") can sometimes result in a mysterious discharge. If that's the culprit, the fix is a fairly simple R&R.

#3 of 35 Re: BMW 5 Series - Battery Problem [roadburner] by bizzymum

Jan 04, 2010 (6:39 am)

Replying to: roadburner (Jan 03, 2010 9:36 am)
I dont know much about cars unfortunately, but everything's been working perfectly and i haven't noticed anything different with the climate control fan. Thanks for the tip. The mechanic has booked the car in with the electrician to check the draw. Thanks again.

#5 of 35 Re: BMW 5 Series - Battery Problem [roadburner] by m1c1

Jan 18, 2010 (12:46 pm)

Replying to: roadburner (Jan 03, 2010 9:36 am)
Hello,
  
I'm experiencing the problem that you've discussed. I bought my 530 BMW (2004, premodel) several years ago, and have experienced my fan turning on during random times as I drive. I noticed a lagg when I turn the ignition, and then in October of last year, my car battery just died. I took my car into a shop that works on only BMWs. After doing some research, I learned that the final stage unit can cause the climate control to act improperly. So when the shop told me the problem was my battery, I questioned them. They said that the problem did not act up when they had my car, and they did not find a draw. I bought a brand new battery from them and went on my way.
  
However, when I took it home, I noticed that the fan did not turn on when I drove it, but instead the fan turned on when the car went to sleep mode. So when I started the car, the fan would be running. I took it back to the shop, they checked it again, and they said that it was blower motor resistor. I was upset that they didn't diagnosis it before and had me buy a battery. I wanted to get a second opinion, and took my car to the BMW dealer. I told the dealer my problem and the technician said it's probably the blower motor. But after they looked at it overnight, the service writer said that they found no draw. This is quiet perculiar to me because my battery keeps on dying. The dealer said that I needed to buy a brand new BMW battery....I told them there is no such thing and there are only a few battery manufactures that everyone buys from.
  
So my car is still not fixed, and my brand new battery is completely dead and has to be jumped. I'm waiting for the new BMW recall list this month hoping the final stage will be on there. Do you know why I'm getting the run around from these companies? It's ridiculous how my problem points to the final stage unit, and the dealer is trying to sell me a battery I don't need. Any advice on what I can do?

#6 of 35 Re: BMW 5 Series - Battery Problem [m1c1] by roadburner

Jan 21, 2010 (5:13 pm)

Replying to: m1c1 (Jan 18, 2010 12:46 pm)
If you have an E60 5 Series have the shop check the Intelligent Battery Sensor(IBS) which is part of the negative battery cable.
If it's an E39, replace the FSU yourself.

#7 of 35 BMW 5 series battry issue by professor6

Jan 27, 2010 (9:38 am)

I have a 2008 535i that is driven short distances to and from work (about 5 minutes each way). The clock sometimes loses its setting, and the BMW technician and BMW's help line both tell me that I need a trickle charger. (They replaced the battery-not a gel filled one-once, and that worked for a few months.) The charger is variously described as 'trickle with auto shut off', 'maintenance charger', and 'float charger'. I am prepared to purchase one, but I prefer to stay away from BMW's private brand ($$$).
 
Anyone with any experience with such a charger?
 
Thanks.

#8 of 35 Re: BMW 5 series battry issue [professor6] by james27

Jan 27, 2010 (3:56 pm)

Replying to: professor6 (Jan 27, 2010 9:38 am)
If they've determined that the battery connections are clean, the alternator is working properly, and the battery is not defective, then any 12v battery charger with a trickle or automatic setting should work. If the 12v outlet is always on, and not switched with the ignition, you can get one that plugs into the cigarette lighter socket. Those are often limited to about 1-2 A, and may not be enough to recharge the battery overnight. ANother thing that should be checked is a leakage or load test to determine if something is not shutting off properly when it should, and thus drawing the battery down. The alarm and clock circuits are the only things that might draw much (and not much) power while the car is off after it has cooled off. The cooling fan on some cars can run after shutdown, but there aren't many other things that do run that draw any significant power. A simple lamp that stays on for some reason can draw a battery down overnight.

#9 of 35 Re: BMW 5 Series - Battery Problem [bizzymum] by id4yuxian

Feb 04, 2010 (1:05 pm)

Replying to: bizzymum (Jan 03, 2010 5:00 am)
I have 2008 550i and have been having the same exact issues with my car as well as with the BMW service center. They replaced my battery after much complaining by me and out of "good faith". I stated to them all these issues in previous posts and they treated me like a fool. I did not appreaciate my experience with them so far. Don't expect to have anything fixed by them.
 
I have been looking into solar trickle chargers but I'm not sure if it will solve your battery problem. I'm still trying to find a cheap resolution to keep my battery from draining. However, according the BMW service center rep, I have to drive my car 45 miles A DAY to maintain the battery charge. That's ridiculous.
 
So far, I have good luck driving my car once every two weeks for a 1/2 hour. 50% of the time i have to redo the clock and date (which I should not have to do).
 
Anyway, my point is I know exactly what you are going through and been told a solar trickle/maintainer might help.

#10 of 35 Re: BMW 5 Series - Battery Problem [id4yuxian] by james27

Feb 04, 2010 (4:21 pm)

Replying to: id4yuxian (Feb 04, 2010 1:05 pm)
If you know how to use a multimeter, you could check the current draw on the battery when everything is off. My guess is it is probably in the low hundreds of milliamps. If it is higher, try pulling fuses to try to isolate what is drawing the power. Many multimeters can measure up to 10A, so don't turn on anything or try to start it, or you'll blow the fuse in the meter. If you can set the interior lights to not come on, do that.
 
Any courtesy lamp that doesn't turn off (trunk, glove box, footwell, engine bay, lighter, etc. can, over time, draw a battery down.

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