I've owned a '90 Westy automatic for 1 month.  It's my first experience with
a Westy, but have lurked on several forums before buying.  I'm very
deficient in my knowledge of battery and electrical technology, so I need to
ask a few very basic questions.

I've been having battery problems.  I started using my Westy locally for
short errands, and on the 10th day, the main battery went dead.  I replaced
the main battery with a new one, and it, too went dead on the 10th day!
It's now recharged, disconnected, and is holding the charge.  (The first one
didn't hold the charge while disconnected.)  Luckily, both times the battery
went dead in my driveway.

The auxiliary battery sticks out of the cavity, so it's probably the wrong
one.  I have the P.O's receipt from Kragen Auto Parts dated Jan., 2006.  It
is a deep cycle battery.  This battery is connected, but only
registers 5.8volts.  I plan to replace it with a battery that fits in
the cavity, but
before I do, I need to know exactly what the Westy's auxiliary battery is
supposed to do, and why it is useful (or unnecessary) to have one.  I am
wondering if it could cause the main battery to drain, and if I should just
disconnect the aux battery and not use it until I replace it with a
correctly fitting one.

I 've downloaded some instructions from this forum's archives on how to
install an auxiliary battery and relay system, but am not quite at that
level of knowledge, yet.  At this point, I just want my main battery to stop
draining every 10 days.  Once that happens, I'll try to find out by reading
if the aux battery has been installed correctly.

I will be very appreciative of any simplified explanations you can offer me.
TIA for your patience.
Patti