BMW iX Multiple Electrical Failures, Alternator Mystery

As a BMW i4 (2020) owner, I faced nearly identical issues last month. The symptoms you're describing match exactly what I experienced, multiple system failures, warning lights, and weak battery performance. In my case, it wasn't the alternator (since these are electric vehicles), but rather a faulty high-voltage battery control module. The main battery was fine, but the control system was sending incorrect voltage readings, causing the vehicle's systems to go haywenir. When I took it to the garage, the diagnostic revealed the battery management system needed recalibration, and one of the monitoring sensors had failed. It was a serious issue that required specialized attention because it affected the entire electrical system. The repair involved replacing the faulty sensor and updating the battery management software. My suggestion would be to get it checked specifically by a certified EV technician who has experience with BMW's electric systems. These symptoms shouldn't be ignored as they can potentially affect critical safety systems.

Thanks for sharing your experience! Really helpful to hear from someone who's been through this. Your solution with the battery control module makes a lot of sense given the symptoms. Just curious, do you remember roughly how much the repair set you back? Also, has everything been running smoothly since the fix? I'd love to know if any other quirks popped up afterward. I'm still a bit nervous about getting it repaired, but hearing your successful fix gives me more confidence about getting it sorted.

Hey there! Glad I could help with my experience. Just wanted to update you, since getting mine fixed, it's been running like a dream! The overvoltage warnings completely disappeared after they replaced that faulty sensor and sorted out the battery issue. Total cost came to 290€, which honestly wasn't as bad as I'd feared given how many warning lights were flashing. Been driving it daily for several weeks now and no weird quirks or issues have shown up. The battery performance is back to normal, and all systems are working perfectly. It really was just that battery control module playing up, exactly like your symptoms. Honestly, once you get it sorted with a good EV tech, you'll probably wonder why you were so worried, these things look scarier than they actually are! My i4 feels like new again, so I'm pretty confident you'll have the same outcome with your iX. Just make sure you get a certified EV specialist on it, and you should be golden.

Thanks so much for the detailed follow-up! Just wanted to let you know I finally got my iX checked out. Took it to a certified BMW EV specialist and turns out you were spot on! Had almost the exact same issue, faulty sensor in the battery management system. The funny thing is, my repair cost was pretty close to yours too, around 300€. Got it back yesterday and wow, what a difference! All those Christmas tree lights on my dashboard are gone, and the car starts up perfectly now. The tech explained everything really clearly, showed me the old sensor and how it was messing with the voltage readings. Should've done this weeks ago instead of worrying about it. Really appreciate you sharing your experience, it helped me make the decision to get it sorted instead of putting it off. Feels great to have my car back to normal. Thanks again for all your help!