BMW 6 Battery Drain Mystery: Owner Seeks Solutions

Hey there! Your issue sounds familiar. I had a similar problem with my 2012 BMW 5 diesel (I also owned a BMW 3 at the time). I have some experience working on cars, but mainly basic maintenance stuff. My battery was draining fast too, and after taking it to my regular workshop, they diagnosed a faulty battery sensor. It wasn't reading the charge state correctly, causing the battery management system to malfunction. The fix was replacing the sensor, cost me around 315 Euro including labor. Before jumping to conclusions though, could you share: How old is your current battery? Are you getting any specific error codes? Does the problem occur even after short parking periods? This info would help figure out if you're dealing with the same issue I had.

Thanks for your detailed response! My car's at 71575 KM and had its last service about two months ago. The battery is actually fairly new, just replaced it last winter. I'm getting the "Battery Discharge" warning, plus some unusual electrical system errors. And yeah, it's happening even after sitting for just 2-3 days. Interesting about the battery sensor issue you mentioned. Definitely sounds similar to what I'm experiencing. Did you notice any warning lights before the sensor completely failed? I'm trying to figure out if I should take it to the shop right away or if it's safe to drive for another week or so.

Yeah, I totally get your concern! Actually, when I had this issue with my BMW 5, I noticed warning lights popping up gradually before things got really bad. First, it was just occasional "Battery Discharge" warnings that would come and go, but then it started getting more frequent. In my case, I kept driving for about two weeks after the first warnings, but honestly, looking back, that wasn't the smartest move. The problem got worse pretty quickly, and one morning I ended up stranded in my driveway because the car wouldn't start at all. Super annoying! Since your symptoms are so similar to what I experienced (especially the 2-3 day discharge issue), and you've already ruled out the battery itself being the problem since it's new, I'd really recommend getting it checked soon. The battery sensor issue might seem minor, but it can actually cause some serious electrical system problems if left unchecked. Quick tip from my experience: make sure they check the whole charging system while they're at it. My mechanic found that the faulty sensor had actually caused some minor damage to other electrical components because I waited too long to get it fixed. Would've saved some money if I'd dealt with it sooner. Let me know how it goes! Curious to hear if it turns out to be the same issue.

Thanks so much for sharing your experience, that's really helpful to know! You're probably right about getting it checked sooner rather than later. Definitely don't want to end up stranded somewhere or cause more damage by waiting too long. I'll call my mechanic tomorrow and get it booked in for next week. Better to deal with it now than risk bigger problems, especially after hearing how your situation played out. The symptoms are just too similar to ignore. Really appreciate you taking the time to explain everything in detail. It's given me a much better idea of what might be going on and what to expect. I'll update once I find out what's actually causing the problem. Thanks again for all the advice! I'll make sure to have them do a full charging system check too, that's a great tip about preventing any knock-on damage. Fingers crossed it's just the sensor and nothing more serious!