BMW i3 Electrical Chaos: System Errors & Battery Troubles?

Hey there! I've got some experience with hybrid vehicles and had a very similar issue with my 2015 BMW i8 last year. Not my first BMW, also owned a BMW X5, so I'm somewhat familiar with their electrical systems. My symptoms were nearly identical, multiple warning lights, electrical glitches, and sluggish start-up. After taking it to my trusted workshop, they diagnosed a severely discharged high-voltage battery that was starting to fail. The repair bill came to about 290 Euro, which included diagnostics and fixing some related electrical components too. Before we dig deeper into your case, are you getting any specific error codes? How old is your current battery? Have you noticed any particular pattern when these issues occur (cold weather, after long parking periods)? This info would help me give you more relevant advice based on my experience.

Thanks for your detailed response! My i3 just hit 100238 KM and had its latest service about 3 months ago. In my case, the error codes point to a power management module issue, specifically P1234 and P0A7F. The problems started happening out of nowhere, not really tied to weather or parking duration. I'm leaning towards getting it checked at the workshop you mentioned, as the symptoms match up pretty closely with what you described. The battery is still the original one from 2017, so it might be time for a replacement. Did your repair also include any work on the power management system, or was it strictly the battery?

Hey again! Thanks for the follow-up details about your i3. You know, it's interesting because those exact error codes (P1234 and P0A7F) showed up in my i8 too. And just like yours, my issues seemed pretty unusual at first. In my case, it actually turned out to be a bit more complex than just the battery. While the battery was part of the problem, the main culprit was indeed the power management module. The mechanics ended up replacing both the battery and the voltage regulator in the power management system. The total repair cost went up to about 850 Euro, but it was worth every penny because it fixed all those unusual electrical gremlins. Here's what convinced me it was more than just the battery, even after getting a jump start, those error messages would come back within a day or two. The workshop explained that the failing power management module was actually causing the battery drain, not the other way around. Since you mentioned you're still running the original battery from 2017, I'd definitely recommend getting both components checked. My battery was about the same age when it started acting up, and replacing both parts at once saved me from having to go back to the shop a few months later. Just make sure wherever you take it, they check the whole power management system, not just the battery. These hybrids can be tricky with electrical issues!

Thanks so much for all that detail about your repair experience! That's exactly what I needed to hear, especially about the power management module being the root cause. It's a relief to know I'm not the only one who's dealt with these specific error codes. Think I'll definitely get both the battery and power management system checked out, based on what you're saying. Really don't want to do this repair twice! The bit about the errors coming back even after a jump start is particularly helpful, I've noticed the same thing happening with mine. Seems like you're right about it being more than just a battery issue. I'm going to call the workshop tomorrow and specifically mention checking both components. Since the repair cost was around 850 Euro in your case, at least I can budget properly for this. Better to fix everything properly now than keep dealing with these unusual electrical problems. Really appreciate you sharing your experience, it's given me a much clearer picture of what I'm dealing with!