Whilst approaching the Dartford Toll tunnel using the outside (fast) lane I experienced long traffic delays which caused many stop/starts and after approx. 10 stops a red warning sign:- Alternator fault, low battery charge confronted me. I immediately switched off the stop/start system and all other electrical gadgets and continued on my journey of another 100 miles trouble free. I spoke to Audi about this who came to the same conclusion as myself which was:- DONT USE STOP/START WHEN IN A TRAFFIC JAM as it will drain the battery.Hope this message is helpful Gordon