NHTSA Complaint #11435705 — 2020 AUDI A8

8/23/2021-I was slowing down at a red light and getting ready to stop but the light turned green and so high pushed on the gas to go before I got to a full stop. The battery warning light came on so I turned around to go back home can you swap cars. My fiancé had to go to work that day and took the vehicle. On his way back going 60 mph on the highway, The power to the vehicle shut down and he was unable to do anything other than slow down and pull off to the side of the road. The vehicle was sent into the Audi dealership and they changed out the 48V battery in the trunk. They also ordered an alternator but did not install it because it start it back up. A couple weeks later (9/25/2021) the same thing happened at a stop sign as I was slowing down but not at a complete stop and hit the gas and the battery light came back on. That light means the battery is disconnected from the engine and once the power runs out, it will shut down again. So I took it straight to the dealership and left it there until they can take a look at it. It’s at the dealership now. There seems to be a flaw in the (stop/go)system of the vehicle when the engine wants to turn off at a stop and when to restart the engine to go. Causing a disconnect of the battery in the trunk to the engine.