BMW i8 Battery Warning Signals, Fix Costs & Solutions

Hey there! I had a similar issue with my 2014 BMW i3 last year. The symptoms were almost identical, starting problems and battery warnings. After taking it to the shop, it turned out the high-voltage battery management system needed recalibration, and the 12V auxiliary battery was failing. The aux battery replacement was straightforward, but the recalibration was more complex and required BMW-specific diagnostic tools. The whole thing took about two days to fix. It was pretty serious since the car was basically immobilized, and these issues can potentially damage other electrical components if left unchecked. Based on your description, it sounds very similar to what I experienced. My advice would be to get it checked at a certified BMW service center since they have the proper diagnostic equipment for hybrid systems. The high-voltage system isn't something you want a regular mechanic messing with. The good news is that once fixed, I haven't had any battery issues since then. Don't wait too long though, these problems tend to get worse if ignored.

Thanks for sharing your experience! This definitely sounds similar to my situation. I'm actually planning to take it to a certified BMW center tomorrow, it's reassuring to hear they were able to sort out your issues properly. Would you mind sharing how much you ended up paying for the whole fix? Also, just curious, have you noticed any other electrical quirks since the repair was done? My anxiety levels about this would drop quite a bit knowing what price range I should expect. Cheers!

Hey again! Happy to give you an update! After taking my i3 to the BMW center, everything was sorted out perfectly. The whole repair came to 290 € for fixing the heavily discharged battery. The best part is that annoying Terminal 30 continuous plus warning completely disappeared after they fixed it. I know you asked about other electrical quirks, honestly, I haven't had a single issue since the repair. The car starts like a dream now, no more warning lights, and all systems are working exactly as they should. Looking back, I was probably more worried than I needed to be! I know you're heading to the dealer tomorrow, and while prices might vary, at least you have a rough idea of what to expect. The peace of mind is totally worth it, these hybrid systems really need proper handling by certified techs who know what they're doing. Just make sure they give you a detailed breakdown of what they're doing. The techs at my service center were great about explaining everything. Good luck with the repair!

Just wanted to update everyone, got my i8 back from the BMW center today and wow, what a relief! The whole experience was way better than I expected. Turns out my problem was pretty similar to what you described with your i3. The techs found that my auxiliary battery was on its last legs and the management system needed a reset. Total bill came to about 350 €, a bit more than yours but still not as scary as I'd feared. The service advisor walked me through everything they did, which was really helpful. Took it for a test drive after picking it up, and it's running like new again. No more warning lights, starts up instantly, and all systems are working perfectly. You were right about getting it done at the certified center, their diagnostic equipment picked up issues my old mechanic probably would've missed. Thanks again for sharing your experience, really helped calm my nerves about the whole situation. Definitely keeping up with the maintenance schedule from now on!