Some of you might know i have the battery drain problem recently,
i changed my 3rd battery two weeks ago and it drained out again last night, :devil:
I brought my car to the local garage and we found out it might caused by the faulty alarm battery.
(I took the car to BMW before and they couldnt find out the problem)

My alarm has mind of his own, it goes off "almost" every time after i locked the car after 10-20 seconds.
And the garage technician suggests the alarm battery might gone so it drains all my car battery overnights and it also makes the car cant get into the sleep mode.
That sounds logical so we tried to find out where the alarm battery is and replace it to see if its work?

So does anyone here knows where the alarm battery is?
Are they built inside the alarm?

We found out the alarm siren is on the right hand side of the rear bumper where near the fuel tank,
but not sure the battery is in the same location.

Any helps would be appreciated!!! As this problem has been with me for more than two years and which is really annoying sometime!

On the E60, I don't believe there is such a thing as an alarm battery.

Clearly, there could be a faulty sensor or module related to the alarm system that's causing your condition -- take a look at the following document to see if it helps shed some light on the subject:

https://5series.net/forums/index.php?autoco...si&img=2784

These bulletins might be useful:

Dead Battery Caused By MPM
http://www.bmwtis.com/tsb/bulletins/bullet...mp/B611205g.htm

Dead Battery - Energy Diagnosis Must Be Performed
http://www.bmwtis.com/tsb/bulletins/bullet...mp/B611305g.htm

Lights Flash Briefly When Vehicle Wakes Up; Battery May Become Discharged
http://www.bmwtis.com/tsb/bulletins/bullet...mp/B630806g.htm

Thanks Rudy and twh!! :thumbsup: :thumbsup: