Flat Battery - How best to avoid ?
 

I last drove my E70 last weekend for several hours everything normal,.. went to use it this weekend, and the battery was down in power and the car wouldnt start. Electrics came and went , but nothing when I pushed the button. The car was in my garage, unlocked and all doors shut all week.

This I thought, was the best way to leave it when not in use, without the alarm being activated, as my experience with my last E53 proved, which suffered a simial problem but it hasnt worked for this E70, something must have been draining power.

I did leave the lights set to auto, but I hardly think that is the cause. Aside from pulling the battery out, charging it, then doing a heavy discharge test on it to see if its retaining power, any ideas/known issues ?

http://bmw.dealerfit.com/store/bmw-m...1389_19437.php

You can charge it via the cigarette lighter :)

It's a common problem.. use the search function for "excessive drain" and you'll find some threads with additional useful information including a BMW SIB on it.

I got the excessive battery drain message and took it to the dealer. They performed the tests suggested by the SIB but didn't find a fault (they updated everything while they had it anyways). Their conclusion was that I was not driving it enough as I mostly drive stop and go for short distances.

Their recommendations were (1) to drive the car at least once each week for at least 30 min and (2) they gave me a charger and told me to charge the battery if I was not able to do #1.

I've never had a car that needed to be plugged in even though my commute has been the same for many years.

Of note, I was working on my other car (08 M3) this weekend and noted that the X5 wakes up periodically with electronic sounds and then shuts off. It makes me wonder if the X5 electronics run in sleep mode while the car is off.

This is sadly a somewhat common problem on X5s. Yes, mine too will "wake up" periodically with electronic R2D2 like sounds, then shut off. Our Z8 needs to be kept on a BMW slow trickle charger if not driven regularly too. Great job BMW! he he he

BMW and electronics... a bad marriage ...I had this problem too, car was at dealer for a full week. They reprogrammed 21 modules, including the so called footrest module, which they thought is the cause of the frequent wakeups. Sad to say that after 4 weeks, I had the problem again. I did not ask them again to have a look at it since I need the car to go to work.

Now I have again issues with electronics (dynamic drive failure). At this current rate of failures, I can drive the car for 4 weeks and then have to bring it in for fixing all the issues...

Sad ...

Common problem in a german X5-Forum as well. As far as I remember, some 20+ cars just in that forum have the same problems (excessive battery drain). People believe it has to do something with the Efficient Dynamics programming. Some people changed battery to a GEL Battery - seemed to work for some of them, but not for all unfortunately.
Me myself had a S-class in family that had to be plugged in literally every night to have the battery charged... until we found out it was absolutely necessary to LOCK the doors when leaving the car in the garage overnight. Otherwise several electronical devices will "test start" once in a while to enable a rapid start up when needed.

That's an interesting idea - perhaps I should try locking it at night in my garage? Since I have comfort access, this involves minimal pain. I'll see if it works.

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2007 E70 4.8 sapphire black/beige
2007 E93 monaco blue/beige
2008 E92 M3 SSII/black

Well that was kind of my question,, if you do lock the doors now on an E70 does this work ?, and will your battery stay charged, cos it didnt on my E53?

keep your car locked ! while unlock, computer is running and draining the battery.