So I have had the car 6 weeks and this weekend the remote on the key I use day to day stopped working. Having unlocked the car, using my phone, it would not allow me to start the car, even when I placed the key on the area in the armrest. Seen on other forums reports of short battery life with not just A6 keys but other models as well. Replaced the battery and all worked fine. Two points have come out of this. Firstly I have now put a spare CR2032 battery in the car in case this should happen when I am a long way from anywhere and would strongly recommend others do the same. I had no prior warning of a low battery in the key before this. Second I think the short battery life issue on the most recent Audis is caused by the design of the key where the "Lock" part stands proud and is easy to get pushed accidently and for long periods of time. Washing the car recently I lost count of the number of times the car locked itself while I had the key in my trouser pocket.