Re: 156 owner
Sorry this is very late, been out of country/busy etc.
The problem was that the battery was being discharged slowly then over night and sometimes within the hour. After disconnecting various systems and isolating the interior lights (mine were staying on because when I shut the doors it caused the master switch near the rear view mirror to flick internally to the 'on' position, due to the switch being badly worn out!) I finally diagnosed the rectifier diode pack in the alternator leaking battery charge to earth. Now for the fun bit!! I bought a bosch alternator instead of the unreliable magneti unit. Removing the alternator from the car involved undoing the front engine and gearbox mounts, removing the drivers side driveshaft from the gearbox differential, removing the waterpump drive pully and the auxilliary belt. Then unbolting the alternator after sliding the engine down and forwards ( carefull not to trap/break fuel lines etc). The reason for all this is that the alternator will not come out from behind the engine otherwise! This is not a task for the faint hearted, also you will need a two post car lift and ....patience!!!