^ In that case the battery needs to be replaced IMO. My Audi battery was like that in 2005 due to very little use of the car as I was in California 95% of the time. I got it jump started then and ran it for a good 1 hour and shut it off but couldnt restart it again. I took it to the Interstate guys and after some quick tests, they said the battery was dead.
But from a use standpoint, it makes sense to leave the battery tender on if the car is going to be idle for a long period of time. With the 2 or 4 amps models it will take forever to get it charged again.
Drive the mofo
