BMW Z4 Terminal 30 Power Issues, Help Needed

Hey there! I have some experience working on BMWs, having owned a 2003 BMW Z3 and later a 325i. I actually faced a very similar issue with my Z3. The symptoms were exactly as you describe, warning lights, tough starts, and those annoying voltage-related codes. Turned out my battery was severely discharged and needed replacement. The workshop ran a thorough diagnostic which showed the battery cells were damaged beyond repair. The whole thing, including labor and diagnostic, cost me around 290 Euro. Before you head to the shop though, could you share: How old is your current battery? Are you getting any specific error codes? Do you notice the issue more after short trips or long parking periods? This info would help me understand if you're dealing with the same problem I had or if there might be something else going on.

Hey, thanks for sharing your experience! My Z4 has 115538 KM on the clock, and I just had it serviced last month. The current battery is about 4 years old, and I'm getting error codes P0562 and P0563. Been noticing it more after short trips, especially in the morning. It's good to know you had a similar experience with your Z3. I was worried it might be something more serious with the alternator or electrical system. I'll probably get the battery tested first before diving deeper into the Terminal 30 issue. These symptoms do sound pretty similar to what you went through.

Hey again! Thanks for providing those details about your Z4. Yeah, those symptoms are eerily similar to what I dealt with on my Z3. When I had the issue, my battery was around 4 years old too, pretty much the same age as yours. Those error codes you're getting (P0562 and P0563) are definitely voltage-related, just like mine were. The fact that you're noticing it more after short trips is also telling, that's exactly how mine started acting up. In my case, I initially thought about checking the Terminal 30 too, but honestly, it turned out to be just the battery. These BMWs are pretty sensitive to battery conditions, and 4 years is typically when they start showing signs of wear. When I replaced mine, all those issues disappeared completely. Quick tip from my experience, make sure you get a proper BMW-spec battery if you end up needing a replacement. I tried to save some money initially with a generic one, and it didn't work out well. Had to replace it again with the right spec battery after just a few months. Let me know what you find out after getting it tested. I'm betting it'll be the same issue I had. And hey, at least it's better than having alternator problems!

Thanks a lot for the detailed follow-up! That's really reassuring to hear, especially about the similar timeline with your battery. You're absolutely right about getting the proper BMW-spec battery, I've heard horror stories about generic ones causing all sorts of electrical gremlins. I've actually just booked an appointment to get the battery tested tomorrow morning. After hearing about your experience, I'm pretty confident this is going to be the solution. It makes total sense now why it's acting up more after short trips, probably not getting enough charge time. Really appreciate you taking the time to share your experience and tips. I'll skip worrying about the Terminal 30 for now and focus on the battery first. Will definitely go with the proper BMW-spec battery if that turns out to be the issue. Amazing how similar our situations are, it's saved me a lot of stress knowing this is likely just a straightforward battery replacement!