My S5 is just over 4.5 years old and I'm starting to get hints that the battery is nearing end of life. However they are only hints, such as stop/start seeming to restart the engine perhaps a bit sooner than it used to. Now on my B5 S4 I remember that every time my battery expired (I think I had 3 or 4 in the 14 years I owned it) it did so without any warning, leaving me with a car that wouldn't start. This always irritated me that if I had just had a bit of warning I could have replaced it and avoided the hassle. But since my B8.5 S5 has a sophisticated (?) power management system I have had the expectation that it would be different. I am expecting that one day I will get a helpful "your battery voltage is low" message on the MMI and/or DIS, but the car will start fine and I can replace the battery at my leisure. Can anyone who has experienced this on the B8.5 possibly confirm that my expectations are correct?