high battery drain again
 

It happened a couple months back but it didn't reappear the next time I started the car. Today it happened again and once again it didn't reappear the next time I started the car.

The only commonality is that each time I used the remote to unlock the car (I have comfort access and rarely use the remote) - today it was to lower all 4 windows with the remote before we got in. No other symptoms or problems other than the warning staying on through that drive, then not again.

Anyone have this problem figured out? I know there are threads in the past but of course it led nowhere really. CD is in there and used like always, had shutdown the car the same as always (comfort access touch). No ipod.

Is there a code stored where the dealer can look into it because I fear they're just going to say un-reproduceable if I bring it in, wasting time I don't have.

I had a software update which allegedly fixes it but didn't, eventually found to be a faulty battery control unit which was preventing the battery from becoming fully charged. There's a whole series of diagnostic regimen that your technician should follow to determine the cause of the fault.

I think it's normal that the warning stays there until you reset it by switching off the ignition. I've noticed at the same time the date/time and trip computer settings are all lost.

I had the same problem a coupe of months back. Wasn't sure what it was and dealer could not pick up anything on the system. I tried different things over time like removing CD's from shuttle, making sure that lights wee not on automatic, etc. Eventually I removed the cigarette lighter from the socket and I've never had a problem since. I'm not sure if that was the problem but since it hasn't happened again, I guess it could be.

I too have had the 'high batter drain' warning a couple of times. All 3 times I didn't have anything on that wasn't supposed to be on. My cig-lighter hasn't been in the socket since day 1 so that can't be the issue for me.

Dont know if any of you guys have considered this.... I was having the same problem and getting a high battery drain message first thing in the morning. I have my cell phone connected thru Bluetooth to the car.... When I park my car in the garage at home and dont lock the doors or dont press the start button a second time to deactivate the 'radio readiness thing' my cell phone still maintains an active bluetooth connection to the car from within my bedroom at home. I think after about 15-20 mins the car shuts off all the power to the bluetooth and other controls within the car and powers down... but I think that sustained connection for 15-20 minutes is draining the battery somewhat. The next day I get the high battery drainage message but the car recharges with that morning drive. I experimented with this a little bit and seems to hold true. When I press the start button a second time to shut off the 'radio readiness' and power down the bluetooth connection (or lock the doors which does the same), I dont get that high battery drain message and vice versa. Could this be a factor in your guys' message? Hope it helps.
KD

^ not in my situation since I do comfort-access lock it every time and bluetooth is hardly ever used these days.

I had this problem and the dealership looked but didn't find a faulty control unit. They concluded it had to do with me driving mostly short trips and gave me a battery charger to use once a week or so. Someone else here suggested that locking the doors whenever not in use made a difference. I've been doing this with no change in driving style and have not had the warning again.:dunno:

> They concluded it had to do with me driving mostly short trips and gave me a battery charger to use once a week or so.

Makes sense if one owns a 1950's vehicle with generator, rather than an alternator, but I would hope new BMWs had something a bit better than 1950's technology for their charging system!

My Z4 sometimes sits for six weeks without being driven or charged, and starts-up with no problem using the four-year old OEM battery.

It is ridiculous for a dealer to say a new vehicle needs to have a battery charger applied regularly due to shhort trips.

I had the same problem, came out to be a bad battery cell (or so the dealer said), they replaced the battery. I did notice that it happened after a week of short drives and a DIY car wash during which I run the radio... Since then I did not really have a week of "short drives" ... :)

weird, the only driving i've been doing recently are [a few hundred] highway miles, as opposed to only local driving the first 2k miles.