Neal

Had the exact same problem with my 91 Vanagon in the last 6 months.  Tried
the same procedure described here.  No luck.  Had to call the NRMA ( our
Auto Club Association ) to jump start me and while arranging to purchase a
new battery I got to speaking to the Patrolman.  He suggested could be a
problem with the alternator.

the Battery service people duly attended, and while fitting a new battery
( ouch my old one was only four years old and just out of warranty ) he
checked the alternator for me.  According to his insturment I was getting
way overcharged like about 130 amps.  This resulted in quicking the demise
of my battery. Cooked it.  Took it to the Auto Electrican and had it fixed.

the point of my message, by all means carry out the checks as mentioned in
the preceeding posts but dont forget to have the charging rate of the Amp
checked, could be overcharging and shortening the life of the battery.  The
alternator has a reguator inbuilt to limit the rate of charge mine went out
maybe you have the same problem.

Ray Hunnam
Penrith Australia.