The manual says it's sufficient for about 30 miles or 50 km. 30 miles for 4.5 liters is 25.2mpg, which sounds reasonable for a 535i that's being driven as if it's low on gas. Does anyone know the USA setting for the low fuel alarm? When I checked the original setting it was at 11 L. I've heard it should be set at 4.5 L? Can anyone confirm? Thanks