BMW iX3 Battery Drain Nightmare: Solutions Needed

Hey there! I've got some experience with EVs, I'd say medium level expertise. I actually faced something very similar with my 2020 BMW iX (also had problems with my i4). The symptoms were exactly like yours, dead battery, warning lights, the whole deal. Turned out my battery sensor was faulty, which was causing incorrect readings and draining the battery. Took it to my regular workshop and they diagnosed it pretty quickly. The sensor was sending wrong signals to the battery management system, causing all sorts of chaos. Got it fixed, cost me about 315 Euro, and haven't had any issues since. Before I can give you more specific advice though, could you share: How long does your car typically sit between drives? What error codes are you getting? Have you noticed any pattern when these issues occur? These details would help figure out if you're dealing with the same problem I had.

Thanks for sharing that info! My iX3 had its last service about 2 months ago at 122051 KM. I typically drive it daily, but recently left it parked for about 5 days while I was away. The main error codes I got were P0562 and P0563 related to system voltage. I'm really hoping it's just the battery sensor like in your case, that seems way less painful than a full battery issue! This is my first EV, so still learning all the quirks. I'll definitely get it checked out soon, as I don't want to risk any long-term damage. Were there any warning signs before your sensor completely failed?

Hey again! Thanks for those details about your iX3. Those voltage codes definitely sound familiar, they're exactly what I saw before my sensor went completely haywire. Since you asked about warning signs, yes, there were a few subtle ones I noticed before the big failure. About a month before everything went wrong, I started seeing slightly dimmer interior lights when first starting up. Also, the infotainment system would occasionally take longer to boot up than usual. I just brushed it off thinking it was normal EV behavior (rookie mistake, right?). With your mileage being similar to what mine was when I had the issue (I was at around 125,000 KM), and those same error codes, I'm even more convinced you're dealing with the same sensor problem. The 5-day parking period probably just made it more obvious. Quick tip from my experience, while you're waiting to get it checked out, try to drive it regularly if possible. I found that longer periods of sitting made the symptoms way worse. Also, when you do take it in, make sure they check the whole charging system, not just the sensor. My mechanic mentioned that these issues can sometimes be interconnected. Want me to share what specific tests they ran to diagnose my sensor? Might help you know what to expect at the service center.

Thanks so much for all that detailed information! That's really helpful to know about the warning signs you experienced. Now that you mention it, I did notice my interior lights seemed a bit dim lately, but like you, I just ignored it thinking it was normal. I've been taking notes of everything you've shared. Yes, please tell me about those diagnostic tests, I'd really like to be prepared when I take it in. I'll definitely try to keep driving it regularly until I can get it serviced. Honestly, it's such a relief to hear this might just be a sensor issue rather than something major with the battery itself. I've already scheduled an appointment for next week, and I'll make sure to mention your experience with the battery sensor to the technicians. I really appreciate you taking the time to share all this, it's made me feel a lot less anxious about the whole situation!

2006 BMW e90 330i DME Power Management failure, idle current violation.

(Translated from Spanish)

Start by checking the battery and alternator to ensure they are functioning properly, as these are common causes of power management issues. Make sure the battery terminals are clean and securely connected. If the problem persists, it might be a good idea to have a professional diagnose the DME (Digital Motor Electronics) system, as it could be a more complex electrical issue. Let me know how it goes or if you have any further questions!