BMW 7 Hybrid Battery Drain: Fix Before Winter Hits

Hey there! I had a similar issue with my 2018 BMW 5 Series Hybrid. The symptoms you're describing match exactly what I experienced, dead battery, warning lights, and those annoying flickering headlights. Last month, my mechanic diagnosed it as a faulty Battery Management System (BMS) sensor. It wasn't just a simple battery replacement job, the sensor was misreading the battery charge levels and causing the car's electrical system to malfunction. This is actually a known issue with BMW hybrids. Had to leave my car at the shop for two days. They replaced the BMS sensor and recalibrated the system. While it wasn't a cheap fix, it wasn't as serious as I initially feared. The car has been running perfectly since then, no more starting issues or warning lights. If you're getting these symptoms, I'd strongly suggest having the BMS checked. It's better to address it soon before it potentially leaves you stranded somewhere. Hope this helps with your decision.

Thanks for sharing your experience! That's really helpful as it sounds exactly like what I'm dealing with. The BMS sensor issue makes a lot of sense given the symptoms. Would you mind sharing what the repair ended up costing you? Also, curious if you've had any other electrical gremlins pop up since getting it fixed last month?

Hey again! Great to hear back from you! Yeah, I'm happy to report that since getting the BMS sensor replaced, my car's been running like a charm. The total bill came to 315 € for the sensor replacement and recalibration work. Initially thought it might be more expensive, but it turned out to be pretty reasonable considering it fixed the problem completely. No electrical gremlins whatsoever since the repair. The battery holds its charge perfectly now, no more dead battery in the morning or those annoying flickering lights. It's actually quite impressive how such a small component can cause so much trouble when it's faulty! The mechanic mentioned these sensors can sometimes go bad on hybrid models, but once replaced, they usually don't give any more trouble. If you decide to get it fixed, make sure they do a full system recalibration after replacing the sensor. That was key in my case. The car feels as good as new now, and I haven't had a single starting issue since. Let me know if you need any other info!

Thanks so much for those details! I just got back from my mechanic today, and you were right, it was the BMS sensor. The repair cost was a bit higher at 380 €, but I'm just relieved it's fixed. The mechanic was much better this time, really took the time to explain everything and even showed me the faulty sensor. The car's starting perfectly now, and all those warning lights are gone. Such a relief! They also did that system recalibration you mentioned, and I can definitely tell the difference. It's running so smoothly now, almost like when I first got it. Really appreciate your help in pointing me in the right direction. Would've probably spent way more time and money troubleshooting without your advice about the BMS sensor. Thanks again for sharing your experience, it made dealing with this whole situation much easier!