BMW 8-Series Battery Woes? Know the Warning Signs

Hi there! I had similar electrical problems with my 2016 BMW 7 Series (had some experience working with cars, but mostly basic maintenance stuff). Those symptoms sound really familiar, my 7 started acting up the same way last year. After the warning lights and weak starts, I took it to my regular workshop. Turned out the auxiliary battery was completely drained. They ran diagnostics, and it wasn't just holding charge anymore. Had to get it replaced, cost me about 290 Euro for parts and labor, but it fixed all those electrical gremlins. Before I can help more specifically, what's the mileage on your 8 Series? Also, have you noticed if the issues get worse after the car sits for a few days without driving? These details would help compare situations better. The 7 and 8 Series share quite a few electrical components, so my experience might be relevant to your case.

Thanks for sharing your experience! I've got 173299 KM on the clock, and yeah, it definitely gets worse after sitting idle. Just had my regular service last month too, but they didn't catch this. Your situation sounds exactly like what I'm dealing with, those unusual warning lights are driving me nuts! Good to know it was a straightforward fix with the auxiliary battery. That price doesn't sound too bad either, considering all the headaches these electrical issues cause. Did you notice any warning signs before it completely started acting up? I'm wondering if I could've caught this earlier.

Hey again! Glad my previous info helped. You know, thinking back about my 7 Series situation, there were actually some subtle signs I missed before it got really bad. About a month before everything went haywire, I noticed the radio would sometimes reset itself when I started the car, lost all my presets and everything. Also, the climate control would occasionally default back to standard settings. With your mileage being similar to what mine was (I was at around 168000 KM when it happened), it's pretty much following the same pattern. These auxiliary batteries typically last 4-5 years, so we're right in that replacement window. The sitting idle thing is a dead giveaway, that's exactly what mine did. The longer it sat, the worse it got. One thing I didn't mention before, after I got it fixed, my mechanic told me I could've potentially spotted it earlier if I'd paid attention to slight delays in the auto start-stop feature. Apparently, when the aux battery starts weakening, the start-stop becomes a bit inconsistent before it completely stops working. Quick tip: when you get it replaced, make sure they register the new battery in the car's computer system. My first mechanic didn't do this, and it caused some weird charging issues until I had it properly registered. Learned that one the hard way!

I'll complete it Thanks for all that detail, that's super helpful! Those early warning signs you mentioned about the radio and climate control resetting actually happened to me too, but I just brushed them off at the time. Can't believe I missed those clues. The start-stop thing makes total sense now, mine was getting really spotty before it completely gave up. Really appreciate the tip about registering the new battery in the system. I'll definitely make sure they do that when I take it in. Think I'll book it for next week, no point letting it get worse. You've basically convinced me it's the auxiliary battery, and honestly, it's a relief knowing it's likely just that and not something more serious. Thanks again for sharing your experience, saved me a lot of worry!