I've been considering and researching a second battery for my 1980
Westfalia since before I even bought it last September.  Unfortunately,
with lots of research, sometimes comes lots of confusion.  So, I'm
looking for advice.  Here's the situation:

I like music.  I like it a lot.  After purchasing my Westfalia, I
installed an aftermarket stereo system.  I installed 4 - 5" Pioneer
speakers, a Pioneer AM/FM/CD Player (low end model), and a Pioneer power
amp driving a nice big sub-woofer in one of those carpeted boxes at the
end of 6' of speaker wire so that I can move it to wherever is most
convenient at any given time.  The sound is excellent!  I think I need
to fine tune the EQ because the stereo seems to have to be so loud that
it hurts my ears when I'm driving.  But, when I am parked it sounds
superb.

After reading through the archives at westfalia.org, I was under the
impression that my best option was to install a second battery that was
exactly the same as my primary battery.  Since I needed a new primary
battery anyway, I purchased two GR41/60 MM72 batteries which seemed to
be the largest ones that would fit in the van.  I immediately installed
the primary but the secondary is still sitting idle under the driver's
seat.  They have actually been rotated a couple of times already because
I was having problems with the starting system.

As I continued my research during the Canadian winter, I realized that
for the type of camping I like to do (long weekend festivals with no
power hook-ups and plenty of need for loud music and cold beer); I would
probably need an alternate power source to ensure that I could live to
my expectations.  I think that I have decided on installing a solar
panel lying flat in the luggage rack over the passenger compartment.
However, I don't have the money right now to make the purchase or the
time to perform the installation.

What I would like to do right now is hook-up the second battery.  I want
it to charge from the alternator when the engine is running, yet be
isolated from the primary batter when the engine is shut off.  I figure
that I should hook the stereo, the sub-woofer, some lighting, and the
fridge to the second battery.  In another few months, I would like to
install the solar panel and connect it to the secondary battery as well.
At that time, I would like the solar panel to charge the second battery
when the van is off, but I would still like to make use of the
alternator for charging the second battery when the van is running.

So, first of all, can I do all this?  Am I missing any important facts?
Secondly, how should I isolate the batteries?  I've read that a relay is
enough, and then I read that a relay isn't enough and I should use an
isolator.  Will either or both of these work with my planned solar panel
setup?  Where can I order the required parts and is this a task that I
can really do myself?

Any assistance or input is GREATLY appreciated.  I want to do this right
and only do it once.

\/\/i!!y

1980 Vanagon "Jazzy"