brian moorcroft

will try not to be to long winded, purchased a 2013 Q7 8 weeks ago, no problems for 3 weeks loved the car. Drove 20 miles into town parked went shopping 2hrs, came back car was completely dead, nothing would work, called AA out and they jump started the cat { no problem} said battery was dead needed new battery. garage fitted new battery and all week no problem. drove to daughters house approx. 25 miles parked came out 2hrs later same issue, no power at all, no central locking lights radio etc., as if the battery was disconnected. back to garage guy kept it and used it for 2 days testing it intermitteredly .No issue for next 10 days then pulled up at traffic lights and lost all power, no dash lights, no Hazzard lights, key would not come out of ignition just dead. had a battery booster and attached that started no problem and now all ok ????????? guy at the garage suggested something to do with earth ? don't want to take to Audi for them to say they can not find the problem and charge me the earth. any thoughts would be most welcome.