Hey! I feel ya. I drive a 2009 Mazda Axela, pretty close to your Mazda Atenza, and faced a similar situation last season. It wasn't a battery issue though, turned out to be a defective control unit. Know it's not what you asked, but the symptoms were quite similar: lights going dim and starting trouble. The bugger was messing with the relay, which made my beast act like the battery was on a permanent siesta. My mechanic did some solid detective work, props to him. He did some checks on the control unit and found it was a goner. He told me it was a serious issue, not rare but one that needed immediate attention. The control unit is like your car's brain, it pretty much controls everything. Switched it out, and it runs smooth as a dream now. Long story short, your issue might not be a self-drained battery. Maybe worth having it checked by your mechanic, you know what they say "a stitch in time" Hope this gives ya a bit of direction!

Hey there! Interesting point about the defective control unit. I never would've expected that to be the culprit. Not to dredge up bad memories, but do you recall how much the fix set you back? Also, has anything else weird popped up on your Mazda since? Appreciate the input!

Hey again! So, after my mechanic identified the rotten apple, it cost me about 600 Euro to squash that bug and replace the defective control unit. No need to say, it was a solid punch to my wallet! And to answer your second question, since squaring things away at the mechanic's, the car's been doing great. In fact, I haven't had any more bouts of unexpectedly drained battery. The improvement has really been night and day – starting is smooth, lights are back to being bright 'n steady. So, that solution truly put paid to the problem. P.S: I learned the hard way that neglected car issues can ring up quite a bill. So, get your Atenza checked sooner than later. Stay safe on those roads!

Hey, thanks a ton for your insights, really appreciate it. Dropping 600 Euro isn't my idea of fun but hearing that your Mazda's been running smoothly ever since is reassuring. Better I bite the bullet now than deal with a complicated, costly repair down the road. Guess it's time I face the music and head to the mechanic. Thanks again for the help happy and safe driving!