I have just fixed 2 VS's lately with the same problem .....flat battery and car stops on them and leaves them in the middle of nowhere.Both phoned up the local racq for assistance and had to be tilt-trayed home.Both cars had about 175 k on the clock. At the back of the alternator on a ecotec v6 on the drivers side is a heavy red wire that is responsible for charging the battery. The lug on this wire gets a loose connection heats up bad and eventually breaks off, leaving a unprotected 12v feed to move around the metal of the engine behind the alternator looking for a earth to set the engine on fire....if you're unlucky. To see it properly you have to take the plastic engine cover off but that is only 4 x 10mm head nuts and look at the back of the alternator. There is a rubber cover over the terminal. Both cars had burnt this wire back for about 10 cms ...so all I had to do is strip the wire back to where the wire was good and barrel lug a new wire with the right 5/16 hole lug on the end of it. Easy fix but not if you are a fair way from home.